diff --git a/include/rawrtc/certificate.h b/include/rawrtc/certificate.h
new file mode 100644
index 0000000..b81d461
--- /dev/null
+++ b/include/rawrtc/certificate.h
@@ -0,0 +1,121 @@
+#pragma once
+#include <rawrtcc/code.h>
+#include <re.h>
+
+/*
+ * Certificate private key types.
+ */
+enum rawrtc_certificate_key_type {
+    // An RSA private key.
+    RAWRTC_CERTIFICATE_KEY_TYPE_RSA = TLS_KEYTYPE_RSA,
+    // An elliptic curve private key.
+    RAWRTC_CERTIFICATE_KEY_TYPE_EC = TLS_KEYTYPE_EC,
+};
+
+/*
+ * Certificate signing hash algorithms.
+ */
+enum rawrtc_certificate_sign_algorithm {
+    // Sign algorithm not set.
+    // Note: When passing this as an argument, a sensible default signing
+    //       algorithm shall be used.
+    RAWRTC_CERTIFICATE_SIGN_ALGORITHM_NONE = 0,
+    // SHA-256 sign algorithm.
+    RAWRTC_CERTIFICATE_SIGN_ALGORITHM_SHA256 = TLS_FINGERPRINT_SHA256,
+    // SHA-384 sign algorithm.
+    RAWRTC_CERTIFICATE_SIGN_ALGORITHM_SHA384,
+    // SHA-512 sign algorithm.
+    RAWRTC_CERTIFICATE_SIGN_ALGORITHM_SHA512,
+};
+
+/*
+ * Certificate encoding.
+ */
+enum rawrtc_certificate_encode {
+    // Only encode the certificate.
+    RAWRTC_CERTIFICATE_ENCODE_CERTIFICATE,
+    // Only encode the private key.
+    RAWRTC_CERTIFICATE_ENCODE_PRIVATE_KEY,
+    // Encode both the certificate and the private key.
+    RAWRTC_CERTIFICATE_ENCODE_BOTH,
+};
+
+/*
+ * Certificate options.
+ */
+struct rawrtc_certificate_options;
+
+/*
+ * Certificate.
+ */
+struct rawrtc_certificate;
+
+/*
+ * Certificates.
+ * Note: Inherits `struct rawrtc_array_container`.
+ */
+struct rawrtc_certificates {
+    size_t n_certificates;
+    struct rawrtc_certificate* certificates[];
+};
+
+/*
+ * Create certificate options.
+ *
+ * All arguments but `key_type` are optional. Sane and safe default
+ * values will be applied, don't worry!
+ *
+ * `*optionsp` must be unreferenced.
+ *
+ * If `common_name` is `NULL` the default common name will be applied.
+ * If `valid_until` is `0` the default certificate lifetime will be
+ * applied.
+ * If the key type is `ECC` and `named_curve` is `NULL`, the default
+ * named curve will be used.
+ * If the key type is `RSA` and `modulus_length` is `0`, the default
+ * amount of bits will be used. The same applies to the
+ * `sign_algorithm` if it has been set to `NONE`.
+ */
+enum rawrtc_code rawrtc_certificate_options_create(
+    struct rawrtc_certificate_options** const optionsp,  // de-referenced
+    enum rawrtc_certificate_key_type const key_type,
+    char* common_name,  // nullable, copied
+    uint_fast32_t valid_until,
+    enum rawrtc_certificate_sign_algorithm sign_algorithm,
+    char* named_curve,  // nullable, copied, ignored for RSA
+    uint_fast32_t modulus_length  // ignored for ECC
+);
+
+/*
+ * Create and generate a self-signed certificate.
+ *
+ * Sane and safe default options will be applied if `options` is
+ * `NULL`.
+ *
+ * `*certificatep` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_certificate_generate(
+    struct rawrtc_certificate** const certificatep,
+    struct rawrtc_certificate_options* options  // nullable
+);
+
+/*
+ * TODO http://draft.ortc.org/#dom-rtccertificate
+ * rawrtc_certificate_from_bytes
+ * rawrtc_certificate_get_expires
+ * rawrtc_certificate_get_fingerprint
+ * rawrtc_certificate_get_algorithm
+ */
+
+/*
+ * Translate a certificate sign algorithm to str.
+ */
+char const* rawrtc_certificate_sign_algorithm_to_str(
+    enum rawrtc_certificate_sign_algorithm const algorithm);
+
+/*
+ * Translate a str to a certificate sign algorithm (case-insensitive).
+ */
+enum rawrtc_code rawrtc_str_to_certificate_sign_algorithm(
+    enum rawrtc_certificate_sign_algorithm* const algorithmp,  // de-referenced
+    char const* const str);
diff --git a/include/rawrtc/config.h.in b/include/rawrtc/config.h.in
new file mode 100644
index 0000000..cfb50f6
--- /dev/null
+++ b/include/rawrtc/config.h.in
@@ -0,0 +1,15 @@
+#pragma once
+
+/// Current version of the library.
+///
+/// Follows [Semantic Versioning 2.0.0](https://semver.org)
+#mesondefine RAWRTC_VERSION
+#mesondefine RAWRTC_VERSION_MAJOR
+#mesondefine RAWRTC_VERSION_MINOR
+#mesondefine RAWRTC_VERSION_PATCH
+
+/// Debug level
+#mesondefine RAWRTC_DEBUG_LEVEL
+
+/// Whether the SCTP redirect transport has been compiled
+#mesondefine RAWRTC_HAVE_SCTP_REDIRECT_TRANSPORT
diff --git a/include/rawrtc/dtls_fingerprint.h b/include/rawrtc/dtls_fingerprint.h
new file mode 100644
index 0000000..437bcbe
--- /dev/null
+++ b/include/rawrtc/dtls_fingerprint.h
@@ -0,0 +1,43 @@
+#pragma once
+#include "certificate.h"
+#include <rawrtcc/code.h>
+#include <re.h>
+
+/*
+ * DTLS fingerprint.
+ */
+struct rawrtc_dtls_fingerprint;
+
+/*
+ * DTLS fingerprints.
+ * Note: Inherits `struct rawrtc_array_container`.
+ */
+struct rawrtc_dtls_fingerprints {
+    size_t n_fingerprints;
+    struct rawrtc_dtls_fingerprint* fingerprints[];
+};
+
+/*
+ * Create a new DTLS fingerprint instance.
+ * `*fingerprintp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_dtls_fingerprint_create(
+    struct rawrtc_dtls_fingerprint** const fingerprintp,  // de-referenced
+    enum rawrtc_certificate_sign_algorithm const algorithm,
+    char* const value  // copied
+);
+
+/*
+ * Get the DTLS certificate fingerprint's sign algorithm.
+ */
+enum rawrtc_code rawrtc_dtls_fingerprint_get_sign_algorithm(
+    enum rawrtc_certificate_sign_algorithm* const sign_algorithmp,  // de-referenced
+    struct rawrtc_dtls_fingerprint* const fingerprint);
+
+/*
+ * Get the DTLS certificate's fingerprint value.
+ * `*valuep` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_dtls_fingerprint_get_value(
+    char** const valuep,  // de-referenced
+    struct rawrtc_dtls_fingerprint* const fingerprint);
diff --git a/include/rawrtc/dtls_parameters.h b/include/rawrtc/dtls_parameters.h
new file mode 100644
index 0000000..ba8df3f
--- /dev/null
+++ b/include/rawrtc/dtls_parameters.h
@@ -0,0 +1,38 @@
+#pragma once
+#include "dtls_transport.h"
+#include <rawrtcc/code.h>
+#include <re.h>
+
+// Dependencies
+struct rawrtc_dtls_fingerprint;
+struct rawrtc_dtls_fingerprints;
+
+/*
+ * DTLS parameters.
+ */
+struct rawrtc_dtls_parameters;
+
+/*
+ * Create a new DTLS parameters instance.
+ * `*parametersp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_dtls_parameters_create(
+    struct rawrtc_dtls_parameters** const parametersp,  // de-referenced
+    enum rawrtc_dtls_role const role,
+    struct rawrtc_dtls_fingerprint* const fingerprints[],  // referenced (each item)
+    size_t const n_fingerprints);
+
+/*
+ * Get the DTLS parameter's role value.
+ */
+enum rawrtc_code rawrtc_dtls_parameters_get_role(
+    enum rawrtc_dtls_role* rolep,  // de-referenced
+    struct rawrtc_dtls_parameters* const parameters);
+
+/*
+ * Get the DTLS parameter's fingerprint array.
+ * `*fingerprintsp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_dtls_parameters_get_fingerprints(
+    struct rawrtc_dtls_fingerprints** const fingerprintsp,  // de-referenced
+    struct rawrtc_dtls_parameters* const parameters);
diff --git a/include/rawrtc/dtls_transport.h b/include/rawrtc/dtls_transport.h
new file mode 100644
index 0000000..c89fcba
--- /dev/null
+++ b/include/rawrtc/dtls_transport.h
@@ -0,0 +1,119 @@
+#pragma once
+#include <rawrtcc/code.h>
+#include <re.h>
+
+// Dependencies
+struct rawrtc_certificate;
+struct rawrtc_dtls_parameters;
+struct rawrtc_ice_transport;
+
+/*
+ * DTLS role.
+ */
+enum rawrtc_dtls_role {
+    RAWRTC_DTLS_ROLE_AUTO,
+    RAWRTC_DTLS_ROLE_CLIENT,
+    RAWRTC_DTLS_ROLE_SERVER,
+};
+
+/*
+ * DTLS transport state.
+ */
+enum rawrtc_dtls_transport_state {
+    RAWRTC_DTLS_TRANSPORT_STATE_NEW,
+    RAWRTC_DTLS_TRANSPORT_STATE_CONNECTING,
+    RAWRTC_DTLS_TRANSPORT_STATE_CONNECTED,
+    RAWRTC_DTLS_TRANSPORT_STATE_CLOSED,
+    RAWRTC_DTLS_TRANSPORT_STATE_FAILED,
+};
+
+/*
+ * DTLS transport.
+ */
+struct rawrtc_dtls_transport;
+
+/*
+ * DTLS transport state change handler.
+ */
+typedef void (*rawrtc_dtls_transport_state_change_handler)(
+    enum rawrtc_dtls_transport_state const state, void* const arg);
+
+/*
+ * DTLS transport error handler.
+ */
+typedef void (*rawrtc_dtls_transport_error_handler)(
+    // TODO: error.message (probably from OpenSSL)
+    void* const arg);
+
+/*
+ * Create a new DTLS transport.
+ * `*transport` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_dtls_transport_create(
+    struct rawrtc_dtls_transport** const transportp,  // de-referenced
+    struct rawrtc_ice_transport* const ice_transport,  // referenced
+    struct rawrtc_certificate* const certificates[],  // copied (each item)
+    size_t const n_certificates,
+    rawrtc_dtls_transport_state_change_handler const state_change_handler,  // nullable
+    rawrtc_dtls_transport_error_handler const error_handler,  // nullable
+    void* const arg  // nullable
+);
+
+/*
+ * Start the DTLS transport.
+ */
+enum rawrtc_code rawrtc_dtls_transport_start(
+    struct rawrtc_dtls_transport* const transport,
+    struct rawrtc_dtls_parameters* const remote_parameters  // copied
+);
+
+/*
+ * Stop and close the DTLS transport.
+ */
+enum rawrtc_code rawrtc_dtls_transport_stop(struct rawrtc_dtls_transport* const transport);
+
+/*
+ * TODO (from RTCIceTransport interface)
+ * rawrtc_certificate_list_*
+ * rawrtc_dtls_transport_get_certificates
+ */
+
+/*
+ * Get the current state of the DTLS transport.
+ */
+enum rawrtc_code rawrtc_dtls_transport_get_state(
+    enum rawrtc_dtls_transport_state* const statep,  // de-referenced
+    struct rawrtc_dtls_transport* const transport);
+
+/*
+ * Get local DTLS parameters of a transport.
+ * `*parametersp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_dtls_transport_get_local_parameters(
+    struct rawrtc_dtls_parameters** const parametersp,  // de-referenced
+    struct rawrtc_dtls_transport* const transport);
+
+/*
+ * TODO (from RTCIceTransport interface)
+ * rawrtc_dtls_transport_get_remote_parameters
+ * rawrtc_dtls_transport_get_remote_certificates
+ * rawrtc_dtls_transport_set_state_change_handler
+ * rawrtc_dtls_transport_set_error_handler
+ */
+
+/*
+ * Get the corresponding name for an ICE transport state.
+ */
+char const* rawrtc_dtls_transport_state_to_name(enum rawrtc_dtls_transport_state const state);
+
+/*
+ * Translate a DTLS role to str.
+ */
+char const* rawrtc_dtls_role_to_str(enum rawrtc_dtls_role const role);
+
+/*
+ * Translate a str to a DTLS role (case-insensitive).
+ */
+enum rawrtc_code rawrtc_str_to_dtls_role(
+    enum rawrtc_dtls_role* const rolep,  // de-referenced
+    char const* const str);
diff --git a/include/rawrtc/ice_candidate.h b/include/rawrtc/ice_candidate.h
new file mode 100644
index 0000000..3d048aa
--- /dev/null
+++ b/include/rawrtc/ice_candidate.h
@@ -0,0 +1,206 @@
+#pragma once
+#include <rawrtcc/code.h>
+#include <re.h>
+#include <netinet/in.h>  // IPPROTO_UDP, IPPROTO_TCP
+
+/*
+ * ICE protocol.
+ */
+enum rawrtc_ice_protocol {
+    RAWRTC_ICE_PROTOCOL_UDP = IPPROTO_UDP,
+    RAWRTC_ICE_PROTOCOL_TCP = IPPROTO_TCP,
+};
+
+/*
+ * ICE candidate type.
+ */
+enum rawrtc_ice_candidate_type {
+    RAWRTC_ICE_CANDIDATE_TYPE_HOST = ICE_CAND_TYPE_HOST,
+    RAWRTC_ICE_CANDIDATE_TYPE_SRFLX = ICE_CAND_TYPE_SRFLX,
+    RAWRTC_ICE_CANDIDATE_TYPE_PRFLX = ICE_CAND_TYPE_PRFLX,
+    RAWRTC_ICE_CANDIDATE_TYPE_RELAY = ICE_CAND_TYPE_RELAY,
+};
+
+/*
+ * ICE TCP candidate type.
+ */
+enum rawrtc_ice_tcp_candidate_type {
+    RAWRTC_ICE_TCP_CANDIDATE_TYPE_ACTIVE = ICE_TCP_ACTIVE,
+    RAWRTC_ICE_TCP_CANDIDATE_TYPE_PASSIVE = ICE_TCP_PASSIVE,
+    RAWRTC_ICE_TCP_CANDIDATE_TYPE_SO = ICE_TCP_SO,
+};
+
+/*
+ * ICE candidate.
+ */
+struct rawrtc_ice_candidate;
+
+/*
+ * ICE candidates.
+ * Note: Inherits `struct rawrtc_array_container`.
+ */
+struct rawrtc_ice_candidates {
+    size_t n_candidates;
+    struct rawrtc_ice_candidate* candidates[];
+};
+
+/*
+ * Create an ICE candidate.
+ * `*candidatep` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_ice_candidate_create(
+    struct rawrtc_ice_candidate** const candidatep,  // de-referenced
+    char* const foundation,  // copied
+    uint32_t const priority,
+    char* const ip,  // copied
+    enum rawrtc_ice_protocol const protocol,
+    uint16_t const port,
+    enum rawrtc_ice_candidate_type const type,
+    enum rawrtc_ice_tcp_candidate_type const tcp_type,
+    char* const related_address,  // copied, nullable
+    uint16_t const related_port);
+
+/*
+ * Get the ICE candidate's foundation.
+ * `*foundationp` will be set to a copy of the IP address that must be
+ * unreferenced.
+ */
+enum rawrtc_code rawrtc_ice_candidate_get_foundation(
+    char** const foundationp,  // de-referenced
+    struct rawrtc_ice_candidate* const candidate);
+
+/*
+ * Get the ICE candidate's priority.
+ */
+enum rawrtc_code rawrtc_ice_candidate_get_priority(
+    uint32_t* const priorityp,  // de-referenced
+    struct rawrtc_ice_candidate* const candidate);
+
+/*
+ * Get the ICE candidate's IP address.
+ * `*ipp` will be set to a copy of the IP address that must be
+ * unreferenced.
+ */
+enum rawrtc_code rawrtc_ice_candidate_get_ip(
+    char** const ipp,  // de-referenced
+    struct rawrtc_ice_candidate* const candidate);
+
+/*
+ * Get the ICE candidate's protocol.
+ */
+enum rawrtc_code rawrtc_ice_candidate_get_protocol(
+    enum rawrtc_ice_protocol* const protocolp,  // de-referenced
+    struct rawrtc_ice_candidate* const candidate);
+
+/*
+ * Get the ICE candidate's port.
+ */
+enum rawrtc_code rawrtc_ice_candidate_get_port(
+    uint16_t* const portp,  // de-referenced
+    struct rawrtc_ice_candidate* const candidate);
+
+/*
+ * Get the ICE candidate's type.
+ */
+enum rawrtc_code rawrtc_ice_candidate_get_type(
+    enum rawrtc_ice_candidate_type* typep,  // de-referenced
+    struct rawrtc_ice_candidate* const candidate);
+
+/*
+ * Get the ICE candidate's TCP type.
+ * Return `RAWRTC_CODE_NO_VALUE` in case the protocol is not TCP.
+ */
+enum rawrtc_code rawrtc_ice_candidate_get_tcp_type(
+    enum rawrtc_ice_tcp_candidate_type* typep,  // de-referenced
+    struct rawrtc_ice_candidate* const candidate);
+
+/*
+ * Get the ICE candidate's related IP address.
+ * `*related_address` will be set to a copy of the related address that
+ * must be unreferenced.
+ *
+ * Return `RAWRTC_CODE_NO_VALUE` in case no related address exists.
+ */
+enum rawrtc_code rawrtc_ice_candidate_get_related_address(
+    char** const related_addressp,  // de-referenced
+    struct rawrtc_ice_candidate* const candidate);
+
+/*
+ * Get the ICE candidate's related IP address' port.
+ * `*related_portp` will be set to a copy of the related address'
+ * port.
+ *
+ * Return `RAWRTC_CODE_NO_VALUE` in case no related port exists.
+ */
+enum rawrtc_code rawrtc_ice_candidate_get_related_port(
+    uint16_t* const related_portp,  // de-referenced
+    struct rawrtc_ice_candidate* const candidate);
+
+/*
+ * Translate a protocol to the corresponding IPPROTO_*.
+ */
+int rawrtc_ice_protocol_to_ipproto(enum rawrtc_ice_protocol const protocol);
+
+/*
+ * Translate a IPPROTO_* to the corresponding protocol.
+ */
+enum rawrtc_code rawrtc_ipproto_to_ice_protocol(
+    enum rawrtc_ice_protocol* const protocolp,  // de-referenced
+    int const ipproto);
+
+/*
+ * Translate an ICE protocol to str.
+ */
+char const* rawrtc_ice_protocol_to_str(enum rawrtc_ice_protocol const protocol);
+
+/*
+ * Translate a pl to an ICE protocol (case-insensitive).
+ */
+enum rawrtc_code rawrtc_pl_to_ice_protocol(
+    enum rawrtc_ice_protocol* const protocolp,  // de-referenced
+    struct pl const* const pl);
+
+/*
+ * Translate a str to an ICE protocol (case-insensitive).
+ */
+enum rawrtc_code rawrtc_str_to_ice_protocol(
+    enum rawrtc_ice_protocol* const protocolp,  // de-referenced
+    char const* const str);
+
+/*
+ * Translate an ICE candidate type to str.
+ */
+char const* rawrtc_ice_candidate_type_to_str(enum rawrtc_ice_candidate_type const type);
+
+/*
+ * Translate a pl to an ICE candidate type (case-insensitive).
+ */
+enum rawrtc_code rawrtc_pl_to_ice_candidate_type(
+    enum rawrtc_ice_candidate_type* const typep,  // de-referenced
+    struct pl const* const pl);
+
+/*
+ * Translate a str to an ICE candidate type (case-insensitive).
+ */
+enum rawrtc_code rawrtc_str_to_ice_candidate_type(
+    enum rawrtc_ice_candidate_type* const typep,  // de-referenced
+    char const* const str);
+
+/*
+ * Translate an ICE TCP candidate type to str.
+ */
+char const* rawrtc_ice_tcp_candidate_type_to_str(enum rawrtc_ice_tcp_candidate_type const type);
+
+/*
+ * Translate a str to an ICE TCP candidate type (case-insensitive).
+ */
+enum rawrtc_code rawrtc_pl_to_ice_tcp_candidate_type(
+    enum rawrtc_ice_tcp_candidate_type* const typep,  // de-referenced
+    struct pl const* const pl);
+
+/*
+ * Translate a str to an ICE TCP candidate type (case-insensitive).
+ */
+enum rawrtc_code rawrtc_str_to_ice_tcp_candidate_type(
+    enum rawrtc_ice_tcp_candidate_type* const typep,  // de-referenced
+    char const* const str);
diff --git a/include/rawrtc/ice_gather_options.h b/include/rawrtc/ice_gather_options.h
new file mode 100644
index 0000000..d850eb5
--- /dev/null
+++ b/include/rawrtc/ice_gather_options.h
@@ -0,0 +1,57 @@
+#pragma once
+#include <rawrtcc/code.h>
+#include <re.h>
+
+/*
+ * ICE gather policy.
+ */
+enum rawrtc_ice_gather_policy {
+    RAWRTC_ICE_GATHER_POLICY_ALL,
+    RAWRTC_ICE_GATHER_POLICY_NOHOST,
+    RAWRTC_ICE_GATHER_POLICY_RELAY,
+};
+
+/*
+ * ICE credential type
+ */
+enum rawrtc_ice_credential_type {
+    RAWRTC_ICE_CREDENTIAL_TYPE_NONE,
+    RAWRTC_ICE_CREDENTIAL_TYPE_PASSWORD,
+    RAWRTC_ICE_CREDENTIAL_TYPE_TOKEN,
+};
+
+/*
+ * ICE gather options.
+ */
+struct rawrtc_ice_gather_options;
+
+/*
+ * Create a new ICE gather options instance.
+ * `*optionsp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_ice_gather_options_create(
+    struct rawrtc_ice_gather_options** const optionsp,  // de-referenced
+    enum rawrtc_ice_gather_policy const gather_policy);
+
+/*
+ * Add an ICE server to the gather options.
+ */
+enum rawrtc_code rawrtc_ice_gather_options_add_server(
+    struct rawrtc_ice_gather_options* const options,
+    char* const* const urls,  // copied
+    size_t const n_urls,
+    char* const username,  // nullable, copied
+    char* const credential,  // nullable, copied
+    enum rawrtc_ice_credential_type const credential_type);
+
+/*
+ * Translate an ICE gather policy to str.
+ */
+char const* rawrtc_ice_gather_policy_to_str(enum rawrtc_ice_gather_policy const policy);
+
+/*
+ * Translate a str to an ICE gather policy (case-insensitive).
+ */
+enum rawrtc_code rawrtc_str_to_ice_gather_policy(
+    enum rawrtc_ice_gather_policy* const policyp,  // de-referenced
+    char const* const str);
diff --git a/include/rawrtc/ice_gatherer.h b/include/rawrtc/ice_gatherer.h
new file mode 100644
index 0000000..2cb7462
--- /dev/null
+++ b/include/rawrtc/ice_gatherer.h
@@ -0,0 +1,118 @@
+#pragma once
+#include <rawrtcc/code.h>
+#include <re.h>
+
+// Dependencies
+struct rawrtc_ice_candidate;
+struct rawrtc_ice_candidates;
+struct rawrtc_ice_gather_options;
+struct rawrtc_ice_parameters;
+
+/*
+ * ICE gatherer state.
+ */
+enum rawrtc_ice_gatherer_state {
+    RAWRTC_ICE_GATHERER_STATE_NEW,
+    RAWRTC_ICE_GATHERER_STATE_GATHERING,
+    RAWRTC_ICE_GATHERER_STATE_COMPLETE,
+    RAWRTC_ICE_GATHERER_STATE_CLOSED,
+};
+
+/*
+ * ICE gatherer.
+ */
+struct rawrtc_ice_gatherer;
+
+/*
+ * ICE gatherer state change handler.
+ */
+typedef void (*rawrtc_ice_gatherer_state_change_handler)(
+    enum rawrtc_ice_gatherer_state const state,  // read-only
+    void* const arg);
+
+/*
+ * ICE gatherer error handler.
+ */
+typedef void (*rawrtc_ice_gatherer_error_handler)(
+    struct rawrtc_ice_candidate* const candidate,  // read-only, nullable
+    char const* const url,  // read-only
+    uint16_t const error_code,  // read-only
+    char const* const error_text,  // read-only
+    void* const arg);
+
+/*
+ * ICE gatherer local candidate handler.
+ * Note: 'candidate' and 'url' will be NULL in case gathering is complete.
+ * 'url' will be NULL in case a host candidate has been gathered.
+ */
+typedef void (*rawrtc_ice_gatherer_local_candidate_handler)(
+    struct rawrtc_ice_candidate* const candidate,
+    char const* const url,  // read-only
+    void* const arg);
+
+/*
+ * Create a new ICE gatherer.
+ * `*gathererp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_ice_gatherer_create(
+    struct rawrtc_ice_gatherer** const gathererp,  // de-referenced
+    struct rawrtc_ice_gather_options* const options,  // referenced
+    rawrtc_ice_gatherer_state_change_handler const state_change_handler,  // nullable
+    rawrtc_ice_gatherer_error_handler const error_handler,  // nullable
+    rawrtc_ice_gatherer_local_candidate_handler const local_candidate_handler,  // nullable
+    void* const arg  // nullable
+);
+
+/*
+ * Close the ICE gatherer.
+ */
+enum rawrtc_code rawrtc_ice_gatherer_close(struct rawrtc_ice_gatherer* const gatherer);
+
+/*
+ * Start gathering using an ICE gatherer.
+ */
+enum rawrtc_code rawrtc_ice_gatherer_gather(
+    struct rawrtc_ice_gatherer* const gatherer,
+    struct rawrtc_ice_gather_options* const options  // referenced, nullable
+);
+
+/*
+ * TODO (from RTCIceGatherer interface)
+ * rawrtc_ice_gatherer_get_component
+ */
+
+/*
+ * Get the current state of an ICE gatherer.
+ */
+enum rawrtc_code rawrtc_ice_gatherer_get_state(
+    enum rawrtc_ice_gatherer_state* const statep,  // de-referenced
+    struct rawrtc_ice_gatherer* const gatherer);
+
+/*
+ * Get local ICE parameters of an ICE gatherer.
+ * `*parametersp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_ice_gatherer_get_local_parameters(
+    struct rawrtc_ice_parameters** const parametersp,  // de-referenced
+    struct rawrtc_ice_gatherer* const gatherer);
+
+/*
+ * Get local ICE candidates of an ICE gatherer.
+ * `*candidatesp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_ice_gatherer_get_local_candidates(
+    struct rawrtc_ice_candidates** const candidatesp,  // de-referenced
+    struct rawrtc_ice_gatherer* const gatherer);
+
+/*
+ * TODO (from RTCIceGatherer interface)
+ * rawrtc_ice_gatherer_create_associated_gatherer (unsupported)
+ * rawrtc_ice_gatherer_set_state_change_handler
+ * rawrtc_ice_gatherer_set_error_handler
+ * rawrtc_ice_gatherer_set_local_candidate_handler
+ */
+
+/*
+ * Get the corresponding name for an ICE gatherer state.
+ */
+char const* rawrtc_ice_gatherer_state_to_name(enum rawrtc_ice_gatherer_state const state);
diff --git a/include/rawrtc/ice_parameters.h b/include/rawrtc/ice_parameters.h
new file mode 100644
index 0000000..c8bd5a0
--- /dev/null
+++ b/include/rawrtc/ice_parameters.h
@@ -0,0 +1,41 @@
+#pragma once
+#include <rawrtcc/code.h>
+#include <re.h>
+
+/*
+ * ICE parameters.
+ */
+struct rawrtc_ice_parameters;
+
+/*
+ * Create a new ICE parameters instance.
+ * `*parametersp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_ice_parameters_create(
+    struct rawrtc_ice_parameters** const parametersp,  // de-referenced
+    char* const username_fragment,  // copied
+    char* const password,  // copied
+    bool const ice_lite);
+
+/*
+ * Get the ICE parameter's username fragment value.
+ * `*username_fragmentp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_ice_parameters_get_username_fragment(
+    char** const username_fragmentp,  // de-referenced
+    struct rawrtc_ice_parameters* const parameters);
+
+/*
+ * Get the ICE parameter's password value.
+ * `*passwordp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_ice_parameters_get_password(
+    char** const passwordp,  // de-referenced
+    struct rawrtc_ice_parameters* const parameters);
+
+/*
+ * Get the ICE parameter's ICE lite value.
+ */
+enum rawrtc_code rawrtc_ice_parameters_get_ice_lite(
+    bool* const ice_litep,  // de-referenced
+    struct rawrtc_ice_parameters* const parameters);
diff --git a/include/rawrtc/ice_server.h b/include/rawrtc/ice_server.h
new file mode 100644
index 0000000..c245732
--- /dev/null
+++ b/include/rawrtc/ice_server.h
@@ -0,0 +1,27 @@
+#pragma once
+#include <rawrtcc/code.h>
+#include <re.h>
+
+/*
+ * ICE server transport protocol.
+ */
+enum rawrtc_ice_server_transport {
+    RAWRTC_ICE_SERVER_TRANSPORT_UDP,
+    RAWRTC_ICE_SERVER_TRANSPORT_TCP,
+    RAWRTC_ICE_SERVER_TRANSPORT_DTLS,
+    RAWRTC_ICE_SERVER_TRANSPORT_TLS,
+};
+
+/*
+ * ICE server.
+ */
+struct rawrtc_ice_server;
+
+/*
+ * ICE servers.
+ * Note: Inherits `struct rawrtc_array_container`.
+ */
+struct rawrtc_ice_servers {
+    size_t n_servers;
+    struct rawrtc_ice_server* servers[];
+};
diff --git a/include/rawrtc/ice_transport.h b/include/rawrtc/ice_transport.h
new file mode 100644
index 0000000..eb08276
--- /dev/null
+++ b/include/rawrtc/ice_transport.h
@@ -0,0 +1,148 @@
+#pragma once
+#include <rawrtcc/code.h>
+#include <re.h>
+
+// Dependencies
+struct rawrtc_ice_candidate;
+struct rawrtc_ice_gatherer;
+struct rawrtc_ice_parameters;
+
+/*
+ * ICE role.
+ */
+enum rawrtc_ice_role {
+    RAWRTC_ICE_ROLE_UNKNOWN = ICE_ROLE_UNKNOWN,
+    RAWRTC_ICE_ROLE_CONTROLLING = ICE_ROLE_CONTROLLING,
+    RAWRTC_ICE_ROLE_CONTROLLED = ICE_ROLE_CONTROLLED,
+};
+
+/*
+ * ICE transport state.
+ */
+enum rawrtc_ice_transport_state {
+    RAWRTC_ICE_TRANSPORT_STATE_NEW,
+    RAWRTC_ICE_TRANSPORT_STATE_CHECKING,
+    RAWRTC_ICE_TRANSPORT_STATE_CONNECTED,
+    RAWRTC_ICE_TRANSPORT_STATE_COMPLETED,
+    RAWRTC_ICE_TRANSPORT_STATE_DISCONNECTED,
+    RAWRTC_ICE_TRANSPORT_STATE_FAILED,
+    RAWRTC_ICE_TRANSPORT_STATE_CLOSED,
+};
+
+/*
+ * ICE transport.
+ */
+struct rawrtc_ice_transport;
+
+/*
+ * ICE transport state change handler.
+ */
+typedef void (*rawrtc_ice_transport_state_change_handler)(
+    enum rawrtc_ice_transport_state const state, void* const arg);
+
+/*
+ * ICE transport pair change handler.
+ */
+typedef void (*rawrtc_ice_transport_candidate_pair_change_handler)(
+    struct rawrtc_ice_candidate* const local,  // read-only
+    struct rawrtc_ice_candidate* const remote,  // read-only
+    void* const arg);
+
+/*
+ * Create a new ICE transport.
+ * `*transportp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_ice_transport_create(
+    struct rawrtc_ice_transport** const transportp,  // de-referenced
+    struct rawrtc_ice_gatherer* const gatherer,  // referenced, nullable
+    rawrtc_ice_transport_state_change_handler const state_change_handler,  // nullable
+    rawrtc_ice_transport_candidate_pair_change_handler const
+        candidate_pair_change_handler,  // nullable
+    void* const arg  // nullable
+);
+
+/*
+ * Start the ICE transport.
+ */
+enum rawrtc_code rawrtc_ice_transport_start(
+    struct rawrtc_ice_transport* const transport,
+    struct rawrtc_ice_gatherer* const gatherer,  // referenced
+    struct rawrtc_ice_parameters* const remote_parameters,  // referenced
+    enum rawrtc_ice_role const role);
+
+/*
+ * Stop and close the ICE transport.
+ */
+enum rawrtc_code rawrtc_ice_transport_stop(struct rawrtc_ice_transport* const transport);
+
+/*
+ * TODO (from RTCIceTransport interface)
+ * rawrtc_ice_transport_get_ice_gatherer
+ */
+
+/*
+ * Get the current ICE role of the ICE transport.
+ */
+enum rawrtc_code rawrtc_ice_transport_get_role(
+    enum rawrtc_ice_role* const rolep,  // de-referenced
+    struct rawrtc_ice_transport* const transport);
+
+/*
+ * TODO
+ * rawrtc_ice_transport_get_component
+ */
+
+/*
+ * Get the current state of the ICE transport.
+ */
+enum rawrtc_code rawrtc_ice_transport_get_state(
+    enum rawrtc_ice_transport_state* const statep,  // de-referenced
+    struct rawrtc_ice_transport* const transport);
+
+/*
+ * rawrtc_ice_transport_get_remote_candidates
+ * rawrtc_ice_transport_get_selected_candidate_pair
+ * rawrtc_ice_transport_get_remote_parameters
+ * rawrtc_ice_transport_create_associated_transport (unsupported)
+ */
+
+/*
+ * Add a remote candidate ot the ICE transport.
+ * Note: 'candidate' must be NULL to inform the transport that the
+ * remote site finished gathering.
+ */
+enum rawrtc_code rawrtc_ice_transport_add_remote_candidate(
+    struct rawrtc_ice_transport* const transport,
+    struct rawrtc_ice_candidate* candidate  // nullable
+);
+
+/*
+ * Set the remote candidates on the ICE transport overwriting all
+ * existing remote candidates.
+ */
+enum rawrtc_code rawrtc_ice_transport_set_remote_candidates(
+    struct rawrtc_ice_transport* const transport,
+    struct rawrtc_ice_candidate* const candidates[],  // referenced (each item)
+    size_t const n_candidates);
+
+/* TODO (from RTCIceTransport interface)
+ * rawrtc_ice_transport_set_state_change_handler
+ * rawrtc_ice_transport_set_candidate_pair_change_handler
+ */
+
+/*
+ * Get the corresponding name for an ICE transport state.
+ */
+char const* rawrtc_ice_transport_state_to_name(enum rawrtc_ice_transport_state const state);
+
+/*
+ * Translate an ICE role to str.
+ */
+char const* rawrtc_ice_role_to_str(enum rawrtc_ice_role const role);
+
+/*
+ * Translate a str to an ICE role (case-insensitive).
+ */
+enum rawrtc_code rawrtc_str_to_ice_role(
+    enum rawrtc_ice_role* const rolep,  // de-referenced
+    char const* const str);
diff --git a/include/rawrtc/main.h b/include/rawrtc/main.h
new file mode 100644
index 0000000..a692961
--- /dev/null
+++ b/include/rawrtc/main.h
@@ -0,0 +1,35 @@
+#pragma once
+#include <rawrtcc/code.h>
+
+/*
+ * Transport layers.
+ */
+enum {
+    RAWRTC_LAYER_SCTP = 20,
+    RAWRTC_LAYER_DTLS_SRTP_STUN = 10,  // TODO: Pretty sure we are able to detect STUN earlier
+    RAWRTC_LAYER_ICE = 0,
+    RAWRTC_LAYER_STUN = -10,
+    RAWRTC_LAYER_TURN = -10,
+};
+
+/*
+ * Configuration.
+ */
+struct rawrtc_config;
+
+/*
+ * Initialise rawrtc. Must be called before making a call to any other
+ * function.
+ *
+ * Note: In case `init_re` is not set to `true`, you MUST initialise
+ *       re yourselves before calling this function.
+ */
+enum rawrtc_code rawrtc_init(bool const init_re);
+
+/*
+ * Close rawrtc and free up all resources.
+ *
+ * Note: In case `close_re` is not set to `true`, you MUST close
+ *       re yourselves.
+ */
+enum rawrtc_code rawrtc_close(bool const close_re);
diff --git a/include/rawrtc/meson.build b/include/rawrtc/meson.build
new file mode 100644
index 0000000..a35c19c
--- /dev/null
+++ b/include/rawrtc/meson.build
@@ -0,0 +1,32 @@
+# Generate configuration header
+configure_file(
+    input: 'config.h.in',
+    output: 'config.h',
+    configuration: configuration,
+    install_dir: '/'.join([get_option('includedir'), 'rawrtc']))
+
+# Install headers
+includes = files([
+    'certificate.h',
+    'dtls_fingerprint.h',
+    'dtls_parameters.h',
+    'dtls_transport.h',
+    'ice_candidate.h',
+    'ice_gather_options.h',
+    'ice_gatherer.h',
+    'ice_parameters.h',
+    'ice_server.h',
+    'ice_transport.h',
+    'main.h',
+    'peer_connection.h',
+    'peer_connection_configuration.h',
+    'peer_connection_description.h',
+    'peer_connection_ice_candidate.h',
+    'peer_connection_state.h',
+    'sctp_transport.h',
+    'utils.h',
+])
+if get_option('sctp_redirect_transport')
+    includes += files('sctp_redirect_transport.h')
+endif
+install_headers(includes, subdir: 'rawrtc')
diff --git a/include/rawrtc/peer_connection.h b/include/rawrtc/peer_connection.h
new file mode 100644
index 0000000..9c962c0
--- /dev/null
+++ b/include/rawrtc/peer_connection.h
@@ -0,0 +1,340 @@
+#pragma once
+#include "ice_gatherer.h"
+#include "ice_transport.h"
+#include "peer_connection_state.h"
+#include <rawrtc/peer_connection_configuration.h>
+#include <rawrtcc/code.h>
+#include <rawrtcdc/data_channel.h>
+#include <rawrtcdc/data_channel_parameters.h>
+#include <re.h>
+
+// Dependencies
+struct rawrtc_peer_connection_description;
+struct rawrtc_peer_connection_ice_candidate;
+
+/*
+ * Peer connection.
+ */
+struct rawrtc_peer_connection;
+
+/*
+ * Peer connection state change handler.
+ */
+typedef void (*rawrtc_peer_connection_state_change_handler)(
+    enum rawrtc_peer_connection_state const state,  // read-only
+    void* const arg);
+
+/*
+ * Negotiation needed handler.
+ */
+typedef void (*rawrtc_negotiation_needed_handler)(void* const arg);
+
+/*
+ * Peer connection ICE local candidate handler.
+ * Note: 'candidate' and 'url' will be NULL in case gathering is complete.
+ * 'url' will be NULL in case a host candidate has been gathered.
+ */
+typedef void (*rawrtc_peer_connection_local_candidate_handler)(
+    struct rawrtc_peer_connection_ice_candidate* const candidate,
+    char const* const url,  // read-only
+    void* const arg);
+
+/*
+ * Peer connection ICE local candidate error handler.
+ * Note: 'candidate' and 'url' will be NULL in case gathering is complete.
+ * 'url' will be NULL in case a host candidate has been gathered.
+ */
+typedef void (*rawrtc_peer_connection_local_candidate_error_handler)(
+    struct rawrtc_peer_connection_ice_candidate* const candidate,  // read-only, nullable
+    char const* const url,  // read-only
+    uint16_t const error_code,  // read-only
+    char const* const error_text,  // read-only
+    void* const arg);
+
+/*
+ * Signaling state handler.
+ */
+typedef void (*rawrtc_signaling_state_change_handler)(
+    enum rawrtc_signaling_state const state,  // read-only
+    void* const arg);
+
+/*
+ * Create a new peer connection.
+ * `*connectionp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_create(
+    struct rawrtc_peer_connection** const connectionp,  // de-referenced
+    struct rawrtc_peer_connection_configuration* configuration,  // referenced
+    rawrtc_negotiation_needed_handler const negotiation_needed_handler,  // nullable
+    rawrtc_peer_connection_local_candidate_handler const local_candidate_handler,  // nullable
+    rawrtc_peer_connection_local_candidate_error_handler const
+        local_candidate_error_handler,  // nullable
+    rawrtc_signaling_state_change_handler const signaling_state_change_handler,  // nullable
+    rawrtc_ice_transport_state_change_handler const
+        ice_connection_state_change_handler,  // nullable
+    rawrtc_ice_gatherer_state_change_handler const ice_gathering_state_change_handler,  // nullable
+    rawrtc_peer_connection_state_change_handler const connection_state_change_handler,  // nullable
+    rawrtc_data_channel_handler const data_channel_handler,  // nullable
+    void* const arg  // nullable
+);
+
+/*
+ * Close the peer connection. This will stop all underlying transports
+ * and results in a final 'closed' state.
+ */
+enum rawrtc_code rawrtc_peer_connection_close(struct rawrtc_peer_connection* const connection);
+
+/*
+ * Create an offer.
+ * `*descriptionp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_create_offer(
+    struct rawrtc_peer_connection_description** const descriptionp,  // de-referenced
+    struct rawrtc_peer_connection* const connection,
+    bool const ice_restart);
+
+/*
+ * Create an answer.
+ * `*descriptionp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_create_answer(
+    struct rawrtc_peer_connection_description** const descriptionp,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Set and apply the local description.
+ */
+enum rawrtc_code rawrtc_peer_connection_set_local_description(
+    struct rawrtc_peer_connection* const connection,
+    struct rawrtc_peer_connection_description* const description  // referenced
+);
+
+/*
+ * Get local description.
+ * Returns `RAWRTC_CODE_NO_VALUE` in case no local description has been
+ * set. Otherwise, `RAWRTC_CODE_SUCCESS` will be returned and
+ * `*descriptionp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_local_description(
+    struct rawrtc_peer_connection_description** const descriptionp,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Set and apply the remote description.
+ */
+enum rawrtc_code rawrtc_peer_connection_set_remote_description(
+    struct rawrtc_peer_connection* const connection,
+    struct rawrtc_peer_connection_description* const description  // referenced
+);
+
+/*
+ * Get remote description.
+ * Returns `RAWRTC_CODE_NO_VALUE` in case no remote description has been
+ * set. Otherwise, `RAWRTC_CODE_SUCCESS` will be returned and
+ * `*descriptionp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_remote_description(
+    struct rawrtc_peer_connection_description** const descriptionp,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Add an ICE candidate to the peer connection.
+ */
+enum rawrtc_code rawrtc_peer_connection_add_ice_candidate(
+    struct rawrtc_peer_connection* const connection,
+    struct rawrtc_peer_connection_ice_candidate* const candidate);
+
+/*
+ * Get the current signalling state of a peer connection.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_signaling_state(
+    enum rawrtc_signaling_state* const statep,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Get the current ICE gathering state of a peer connection.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_ice_gathering_state(
+    enum rawrtc_ice_gatherer_state* const statep,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Get the current ICE connection state of a peer connection.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_ice_connection_state(
+    enum rawrtc_ice_transport_state* const statep,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Get the current (peer) connection state of the peer connection.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_connection_state(
+    enum rawrtc_peer_connection_state* const statep,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Get indication whether the remote peer accepts trickled ICE
+ * candidates.
+ *
+ * Returns `RAWRTC_CODE_NO_VALUE` in case no remote description has been
+ * set.
+ */
+enum rawrtc_code rawrtc_peer_connection_can_trickle_ice_candidates(
+    bool* const can_trickle_ice_candidatesp,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Create a data channel on a peer connection.
+ * `*channelp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_create_data_channel(
+    struct rawrtc_data_channel** const channelp,  // de-referenced
+    struct rawrtc_peer_connection* const connection,
+    struct rawrtc_data_channel_parameters* const parameters,  // referenced
+    rawrtc_data_channel_open_handler const open_handler,  // nullable
+    rawrtc_data_channel_buffered_amount_low_handler const buffered_amount_low_handler,  // nullable
+    rawrtc_data_channel_error_handler const error_handler,  // nullable
+    rawrtc_data_channel_close_handler const close_handler,  // nullable
+    rawrtc_data_channel_message_handler const message_handler,  // nullable
+    void* const arg  // nullable
+);
+
+/*
+ * Unset the handler argument and all handlers of the peer connection.
+ */
+enum rawrtc_code rawrtc_peer_connection_unset_handlers(
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Set the peer connection's negotiation needed handler.
+ */
+enum rawrtc_code rawrtc_peer_connection_set_negotiation_needed_handler(
+    struct rawrtc_peer_connection* const connection,
+    rawrtc_negotiation_needed_handler const negotiation_needed_handler  // nullable
+);
+
+/*
+ * Get the peer connection's negotiation needed handler.
+ * Returns `RAWRTC_CODE_NO_VALUE` in case no handler has been set.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_negotiation_needed_handler(
+    rawrtc_negotiation_needed_handler* const negotiation_needed_handlerp,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Set the peer connection's ICE local candidate handler.
+ */
+enum rawrtc_code rawrtc_peer_connection_set_local_candidate_handler(
+    struct rawrtc_peer_connection* const connection,
+    rawrtc_peer_connection_local_candidate_handler const local_candidate_handler  // nullable
+);
+
+/*
+ * Get the peer connection's ICE local candidate handler.
+ * Returns `RAWRTC_CODE_NO_VALUE` in case no handler has been set.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_local_candidate_handler(
+    rawrtc_peer_connection_local_candidate_handler* const
+        local_candidate_handlerp,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Set the peer connection's ICE local candidate error handler.
+ */
+enum rawrtc_code rawrtc_peer_connection_set_local_candidate_error_handler(
+    struct rawrtc_peer_connection* const connection,
+    rawrtc_peer_connection_local_candidate_error_handler const
+        local_candidate_error_handler  // nullable
+);
+
+/*
+ * Get the peer connection's ICE local candidate error handler.
+ * Returns `RAWRTC_CODE_NO_VALUE` in case no handler has been set.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_local_candidate_error_handler(
+    rawrtc_peer_connection_local_candidate_error_handler* const
+        local_candidate_error_handlerp,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Set the peer connection's signaling state change handler.
+ */
+enum rawrtc_code rawrtc_peer_connection_set_signaling_state_change_handler(
+    struct rawrtc_peer_connection* const connection,
+    rawrtc_signaling_state_change_handler const signaling_state_change_handler  // nullable
+);
+
+/*
+ * Get the peer connection's signaling state change handler.
+ * Returns `RAWRTC_CODE_NO_VALUE` in case no handler has been set.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_signaling_state_change_handler(
+    rawrtc_signaling_state_change_handler* const signaling_state_change_handlerp,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Set the peer connection's ice connection state change handler.
+ */
+enum rawrtc_code rawrtc_peer_connection_set_ice_connection_state_change_handler(
+    struct rawrtc_peer_connection* const connection,
+    rawrtc_ice_transport_state_change_handler const ice_connection_state_change_handler  // nullable
+);
+
+/*
+ * Get the peer connection's ice connection state change handler.
+ * Returns `RAWRTC_CODE_NO_VALUE` in case no handler has been set.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_ice_connection_state_change_handler(
+    rawrtc_ice_transport_state_change_handler* const
+        ice_connection_state_change_handlerp,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Set the peer connection's ice gathering state change handler.
+ */
+enum rawrtc_code rawrtc_peer_connection_set_ice_gathering_state_change_handler(
+    struct rawrtc_peer_connection* const connection,
+    rawrtc_ice_gatherer_state_change_handler const ice_gathering_state_change_handler  // nullable
+);
+
+/*
+ * Get the peer connection's ice gathering state change handler.
+ * Returns `RAWRTC_CODE_NO_VALUE` in case no handler has been set.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_ice_gathering_state_change_handler(
+    rawrtc_ice_gatherer_state_change_handler* const
+        ice_gathering_state_change_handlerp,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Set the peer connection's (peer) connection state change handler.
+ */
+enum rawrtc_code rawrtc_peer_connection_set_connection_state_change_handler(
+    struct rawrtc_peer_connection* const connection,
+    rawrtc_peer_connection_state_change_handler const connection_state_change_handler  // nullable
+);
+
+/*
+ * Get the peer connection's (peer) connection state change handler.
+ * Returns `RAWRTC_CODE_NO_VALUE` in case no handler has been set.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_connection_state_change_handler(
+    rawrtc_peer_connection_state_change_handler* const
+        connection_state_change_handlerp,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
+
+/*
+ * Set the peer connection's data channel handler.
+ */
+enum rawrtc_code rawrtc_peer_connection_set_data_channel_handler(
+    struct rawrtc_peer_connection* const connection,
+    rawrtc_data_channel_handler const data_channel_handler  // nullable
+);
+
+/*
+ * Get the peer connection's data channel handler.
+ * Returns `RAWRTC_CODE_NO_VALUE` in case no handler has been set.
+ */
+enum rawrtc_code rawrtc_peer_connection_get_data_channel_handler(
+    rawrtc_data_channel_handler* const data_channel_handlerp,  // de-referenced
+    struct rawrtc_peer_connection* const connection);
diff --git a/include/rawrtc/peer_connection_configuration.h b/include/rawrtc/peer_connection_configuration.h
new file mode 100644
index 0000000..d32a02b
--- /dev/null
+++ b/include/rawrtc/peer_connection_configuration.h
@@ -0,0 +1,96 @@
+#pragma once
+#include "ice_gather_options.h"
+#include <rawrtcc/code.h>
+#include <rawrtcdc/sctp_transport.h>
+#include <re.h>
+
+// Dependencies
+struct rawrtc_certificate;
+struct rawrtc_certificates;
+struct rawrtc_ice_servers;
+
+/*
+ * Peer connection configuration.
+ */
+struct rawrtc_peer_connection_configuration;
+
+/*
+ * Create a new peer connection configuration.
+ * `*configurationp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_configuration_create(
+    struct rawrtc_peer_connection_configuration** const configurationp,  // de-referenced
+    enum rawrtc_ice_gather_policy const gather_policy);
+
+/*
+ * Add an ICE server to the peer connection configuration.
+ */
+enum rawrtc_code rawrtc_peer_connection_configuration_add_ice_server(
+    struct rawrtc_peer_connection_configuration* const configuration,
+    char* const* const urls,  // copied
+    size_t const n_urls,
+    char* const username,  // nullable, copied
+    char* const credential,  // nullable, copied
+    enum rawrtc_ice_credential_type const credential_type);
+
+/*
+ * Get ICE servers from the peer connection configuration.
+ * `*serversp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_configuration_get_ice_servers(
+    struct rawrtc_ice_servers** const serversp,  // de-referenced
+    struct rawrtc_peer_connection_configuration* const configuration);
+
+/*
+ * Add a certificate to the peer connection configuration to be used
+ * instead of an ephemerally generated one.
+ */
+enum rawrtc_code rawrtc_peer_connection_configuration_add_certificate(
+    struct rawrtc_peer_connection_configuration* configuration,
+    struct rawrtc_certificate* const certificate  // copied
+);
+
+/*
+ * Get certificates from the peer connection configuration.
+ * `*certificatesp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_configuration_get_certificates(
+    struct rawrtc_certificates** const certificatesp,  // de-referenced
+    struct rawrtc_peer_connection_configuration* const configuration);
+
+/*
+ * Set whether to use legacy SDP for data channel parameter encoding.
+ * Note: Legacy SDP for data channels is on by default due to parsing problems in Chrome.
+ */
+enum rawrtc_code rawrtc_peer_connection_configuration_set_sctp_sdp_05(
+    struct rawrtc_peer_connection_configuration* configuration, bool on);
+
+/*
+ * Set the SCTP transport's send and receive buffer length in bytes.
+ * If both values are zero, the default buffer length will be used. Otherwise,
+ * zero is invalid.
+ */
+enum rawrtc_code rawrtc_peer_connection_configuration_set_sctp_buffer_length(
+    struct rawrtc_peer_connection_configuration* configuration,
+    uint32_t send_buffer_length,
+    uint32_t receive_buffer_length);
+
+/*
+ * Set the SCTP transport's congestion control algorithm.
+ */
+enum rawrtc_code rawrtc_peer_connection_configuration_set_sctp_congestion_ctrl_algorithm(
+    struct rawrtc_peer_connection_configuration* configuration,
+    enum rawrtc_sctp_transport_congestion_ctrl algorithm);
+
+/*
+ * Set the SCTP transport's maximum transmission unit (MTU).
+ * A value of zero indicates that the default MTU should be used.
+ */
+enum rawrtc_code rawrtc_peer_connection_configuration_set_sctp_mtu(
+    struct rawrtc_peer_connection_configuration* configuration, uint32_t mtu);
+
+/*
+ * Enable or disable MTU discovery on the SCTP transport.
+ */
+enum rawrtc_code rawrtc_peer_connection_configuration_set_sctp_mtu_discovery(
+    struct rawrtc_peer_connection_configuration* configuration, bool on);
diff --git a/include/rawrtc/peer_connection_description.h b/include/rawrtc/peer_connection_description.h
new file mode 100644
index 0000000..8befa52
--- /dev/null
+++ b/include/rawrtc/peer_connection_description.h
@@ -0,0 +1,54 @@
+#pragma once
+#include <rawrtcc/code.h>
+#include <re.h>
+
+/*
+ * SDP type.
+ */
+enum rawrtc_sdp_type {
+    RAWRTC_SDP_TYPE_OFFER,
+    RAWRTC_SDP_TYPE_PROVISIONAL_ANSWER,
+    RAWRTC_SDP_TYPE_ANSWER,
+    RAWRTC_SDP_TYPE_ROLLBACK,
+};
+
+/*
+ * Peer connection description.
+ */
+struct rawrtc_peer_connection_description;
+
+/*
+ * Create a description by parsing it from SDP.
+ * `*descriptionp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_description_create(
+    struct rawrtc_peer_connection_description** const descriptionp,  // de-referenced
+    enum rawrtc_sdp_type const type,
+    char const* const sdp);
+
+/*
+ * Get the SDP type of the description.
+ */
+enum rawrtc_code rawrtc_peer_connection_description_get_sdp_type(
+    enum rawrtc_sdp_type* const typep,  // de-referenced
+    struct rawrtc_peer_connection_description* const description);
+
+/*
+ * Get the SDP of the description.
+ * `*sdpp` will be set to a copy of the SDP that must be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_description_get_sdp(
+    char** const sdpp,  // de-referenced
+    struct rawrtc_peer_connection_description* const description);
+
+/*
+ * Translate an SDP type to str.
+ */
+char const* rawrtc_sdp_type_to_str(enum rawrtc_sdp_type const type);
+
+/*
+ * Translate a str to an SDP type.
+ */
+enum rawrtc_code rawrtc_str_to_sdp_type(
+    enum rawrtc_sdp_type* const typep,  // de-referenced
+    char const* const str);
diff --git a/include/rawrtc/peer_connection_ice_candidate.h b/include/rawrtc/peer_connection_ice_candidate.h
new file mode 100644
index 0000000..180a6f5
--- /dev/null
+++ b/include/rawrtc/peer_connection_ice_candidate.h
@@ -0,0 +1,83 @@
+#pragma once
+#include <rawrtcc/code.h>
+#include <re.h>
+
+// Dependencies
+struct rawrtc_ice_candidate;
+
+/*
+ * Peer connection ICE candidate.
+ */
+struct rawrtc_peer_connection_ice_candidate;
+
+/*
+ * Create a new ICE candidate from SDP.
+ * `*candidatesp` must be unreferenced.
+ *
+ * Note: This is equivalent to creating an `RTCIceCandidate` from an
+ *       `RTCIceCandidateInit` instance in the W3C WebRTC
+ *       specification.
+ */
+enum rawrtc_code rawrtc_peer_connection_ice_candidate_create(
+    struct rawrtc_peer_connection_ice_candidate** const candidatep,  // de-referenced
+    char* const sdp,
+    char* const mid,  // nullable, copied
+    uint8_t const* const media_line_index,  // nullable, copied
+    char* const username_fragment  // nullable, copied
+);
+
+/*
+ * Encode the ICE candidate into SDP.
+ * `*sdpp` will be set to a copy of the SDP attribute that must be
+ * unreferenced.
+ *
+ * Note: This is equivalent to the `candidate` attribute of the W3C
+ *       WebRTC specification's `RTCIceCandidateInit`.
+ */
+enum rawrtc_code rawrtc_peer_connection_ice_candidate_get_sdp(
+    char** const sdpp,  // de-referenced
+    struct rawrtc_peer_connection_ice_candidate* const candidate);
+
+/*
+ * Get the media stream identification tag the ICE candidate is
+ * associated to.
+ * `*midp` will be set to a copy of the candidate's mid and must be
+ * unreferenced.
+ *
+ * Return `RAWRTC_CODE_NO_VALUE` in case no 'mid' has been set.
+ * Otherwise, `RAWRTC_CODE_SUCCESS` will be returned and `*midp* must
+ * be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_ice_candidate_get_sdp_mid(
+    char** const midp,  // de-referenced
+    struct rawrtc_peer_connection_ice_candidate* const candidate);
+
+/*
+ * Get the media stream line index the ICE candidate is associated to.
+ * Return `RAWRTC_CODE_NO_VALUE` in case no media line index has been
+ * set.
+ */
+enum rawrtc_code rawrtc_peer_connection_ice_candidate_get_sdp_media_line_index(
+    uint8_t* const media_line_index,  // de-referenced
+    struct rawrtc_peer_connection_ice_candidate* const candidate);
+
+/*
+ * Get the username fragment the ICE candidate is associated to.
+ * `*username_fragmentp` will be set to a copy of the candidate's
+ * username fragment and must be unreferenced.
+ *
+ * Return `RAWRTC_CODE_NO_VALUE` in case no username fragment has been
+ * set. Otherwise, `RAWRTC_CODE_SUCCESS` will be returned and
+ * `*username_fragmentp* must be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_ice_candidate_get_username_fragment(
+    char** const username_fragmentp,  // de-referenced
+    struct rawrtc_peer_connection_ice_candidate* const candidate);
+
+/*
+ * Get the underlying ORTC ICE candidate from the ICE candidate.
+ * `*ortc_candidatep` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_peer_connection_ice_candidate_get_ortc_candidate(
+    struct rawrtc_ice_candidate** const ortc_candidatep,  // de-referenced
+    struct rawrtc_peer_connection_ice_candidate* const candidate);
diff --git a/include/rawrtc/peer_connection_state.h b/include/rawrtc/peer_connection_state.h
new file mode 100644
index 0000000..6649734
--- /dev/null
+++ b/include/rawrtc/peer_connection_state.h
@@ -0,0 +1,35 @@
+#pragma once
+
+/*
+ * Signalling state.
+ */
+enum rawrtc_signaling_state {
+    RAWRTC_SIGNALING_STATE_STABLE,
+    RAWRTC_SIGNALING_STATE_HAVE_LOCAL_OFFER,
+    RAWRTC_SIGNALING_STATE_HAVE_REMOTE_OFFER,
+    RAWRTC_SIGNALING_STATE_HAVE_LOCAL_PROVISIONAL_ANSWER,
+    RAWRTC_SIGNALING_STATE_HAVE_REMOTE_PROVISIONAL_ANSWER,
+    RAWRTC_SIGNALING_STATE_CLOSED,
+};
+
+/*
+ * Peer connection state.
+ */
+enum rawrtc_peer_connection_state {
+    RAWRTC_PEER_CONNECTION_STATE_NEW,
+    RAWRTC_PEER_CONNECTION_STATE_CONNECTING,
+    RAWRTC_PEER_CONNECTION_STATE_CONNECTED,
+    RAWRTC_PEER_CONNECTION_STATE_DISCONNECTED,
+    RAWRTC_PEER_CONNECTION_STATE_FAILED,
+    RAWRTC_PEER_CONNECTION_STATE_CLOSED,
+};
+
+/*
+ * Get the corresponding name for a signaling state.
+ */
+char const* rawrtc_signaling_state_to_name(enum rawrtc_signaling_state const state);
+
+/*
+ * Get the corresponding name for a peer connection state.
+ */
+char const* rawrtc_peer_connection_state_to_name(enum rawrtc_peer_connection_state const state);
diff --git a/include/rawrtc/sctp_redirect_transport.h b/include/rawrtc/sctp_redirect_transport.h
new file mode 100644
index 0000000..80a9d8c
--- /dev/null
+++ b/include/rawrtc/sctp_redirect_transport.h
@@ -0,0 +1,27 @@
+#pragma once
+#include <rawrtcc/code.h>
+#include <rawrtcdc/sctp_redirect_transport.h>
+#include <re.h>
+
+// Dependencies
+struct rawrtc_dtls_transport;
+
+/*
+ * Create an SCTP redirect transport.
+ * `*transportp` must be unreferenced.
+ *
+ * `port` defaults to `5000` if set to `0`.
+ * `redirect_ip` is the target IP SCTP packets will be redirected to
+ *  and must be a IPv4 address.
+ * `redirect_port` is the target SCTP port packets will be redirected
+ *  to.
+ */
+enum rawrtc_code rawrtc_sctp_redirect_transport_create(
+    struct rawrtc_sctp_redirect_transport** const transportp,  // de-referenced
+    struct rawrtc_dtls_transport* const dtls_transport,  // referenced
+    uint16_t const port,  // zeroable
+    char* const redirect_ip,  // copied
+    uint16_t const redirect_port,
+    rawrtc_sctp_redirect_transport_state_change_handler const state_change_handler,  // nullable
+    void* const arg  // nullable
+);
diff --git a/include/rawrtc/sctp_transport.h b/include/rawrtc/sctp_transport.h
new file mode 100644
index 0000000..59c365f
--- /dev/null
+++ b/include/rawrtc/sctp_transport.h
@@ -0,0 +1,21 @@
+#pragma once
+#include <rawrtcc/code.h>
+#include <rawrtcdc/data_channel.h>
+#include <rawrtcdc/sctp_transport.h>
+#include <re.h>
+
+// Dependencies
+struct rawrtc_dtls_transport;
+
+/*
+ * Create an SCTP transport.
+ * `*transportp` must be unreferenced.
+ */
+enum rawrtc_code rawrtc_sctp_transport_create(
+    struct rawrtc_sctp_transport** const transportp,  // de-referenced
+    struct rawrtc_dtls_transport* const dtls_transport,  // referenced
+    uint16_t const port,  // zeroable
+    rawrtc_data_channel_handler const data_channel_handler,  // nullable
+    rawrtc_sctp_transport_state_change_handler const state_change_handler,  // nullable
+    void* const arg  // nullable
+);
diff --git a/include/rawrtc/utils.h b/include/rawrtc/utils.h
new file mode 100644
index 0000000..94f63b9
--- /dev/null
+++ b/include/rawrtc/utils.h
@@ -0,0 +1,10 @@
+#pragma once
+#include <re.h>
+
+/*
+ * Array container.
+ */
+struct rawrtc_array_container {
+    size_t n_items;
+    void* items[];
+};