The Freesound APIv2 exposes the CC-licensed sound library over HTTP for programmatic search and retrieval

The Freesound APIv2 (introduced 2011) is a REST/HTTP interface to the entire library of Creative Commons–licensed sounds, turning Freesound from a click-through website into a queryable, licensable sample source that a live-coding rig or generative instrument can integrate directly. It supports text and audio-similarity search; browsing sounds, packs and users; filtering results by CC license type; downloading previews or original files; retrieving automatically extracted audio features (timbre, spectral characteristics, pitch, etc., computed by the Essentia library); and social actions like uploading, commenting, rating and bookmarking. A free API credential (requested at freesound.org/apiv2/apply) is required: basic read calls authenticate with an API key passed as a token request parameter, while some resources require OAuth2. Official client libraries exist for Python, JavaScript and JUCE/C++, with community clients for Max/MSP, SuperCollider and others.

Examples

curl: https://freesound.org/apiv2/search/text/?query=piano&token=YOUR_API_KEY returns paginated JSON of CC piano sounds. Python: client.text_search(query='dog', filter='duration:[0.0 TO 15.0] avg_rating:[4.5 TO 5.0] license:"Creative Commons 0"') returns short, highly-rated CC0 dog samples. A SuperCollider patch can call the API to load a fresh field-recording sample each performance.

Assessment

State what a Freesound API credential is for and how a basic search request supplies it. Name three things the API can filter or retrieve beyond an audio file (e.g. extracted features, similar sounds, pack/user info, CC-license filter), and explain why the license filter matters for commercial use.