4chan vs Lanyard

4chan's API serves the same read-only board and thread data every page renders — board lists, catalogs, threads, and posts — as plain JSON from the dedicated a.4cdn.org host, with no registration, key, or authentication of any kind required. Media referenced by posts is served from the sibling i.4cdn.org host, and the project's own GitHub repository (4chan/4chan-API) hosts the reference client and doubles as the canonical documentation, including the rule to cap requests at one per second. Cross-origin use from a browser is limited in practice: both the docs and a live probe confirm the API's CORS policy only allows requests originating from 4chan's own board pages, so a third-party site must proxy requests server-side rather than call it directly from client-side JavaScript.

Lanyard exposes a Discord user's live presence — online status, current activities (games, Spotify listening data), and any custom key-value data set via their Discord bio — over a free public REST endpoint or a subscribable WebSocket feed, with no authentication required. The catch is that both the requester and the target user must share a Discord server with Lanyard's bot, since Discord's gateway only surfaces presence data for mutual-guild members.