4chan vs Bluesky

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.

Bluesky is the decentralized social network built on the AT Protocol, where posts, follows, and identity live on portable Personal Data Servers instead of one company's database. Its public AppView at public.api.bsky.app exposes keyless, read-only XRPC methods such as app.bsky.actor.getProfile and app.bsky.feed.getAuthorFeed, so any client can pull public profiles and feeds without registering an app. Posting, following, or reading a signed-in user's private data instead requires an authenticated session against a Personal Data Server via an app password or OAuth, not a single global API key.