Developers

DFOS gives you four ways to build on top of a space. Each one is public, and each has its own section below.

• DFOS API — an HTTP API at api.dfos.com over public spaces, posts, pages, and profiles. Most reads are anonymous: no key and no account needed, and every anonymous response is the same for any caller. With a user's consent you can also read what they can see and post, comment, and upvote as them. Start with the quickstart, or open the interactive reference to try every endpoint.
• Sign in with DFOS — let people sign in to your own app with their DFOS identity, and — if they consent — read their profile, their memberships, or the posts and comments they can see, and write as them in the spaces they name. Serve a dfos-app.json document at your domain, or prove your key from a local port if you have no domain at all; there is no registration step either way. The setup recipe takes you from nothing to a working sign-in button, one step at a time, and Local applications is the same road for a CLI, an agent, or a desktop app.
• Agents & connected apps — connect an AI agent to your own DFOS account over the Model Context Protocol. A connected agent acts as you: it can read your spaces, post, message, search, and browse these docs on your behalf.
• Protocol — the open identity and authorship layer underneath DFOS. Every identity and every public post is cryptographically verifiable against a public relay, with no DFOS account and no trust in our servers.

New to the API? The quickstart walks one happy path end to end. Adding a sign-in button to your app? Start with Sign in with DFOS, then run the setup recipe. Building a CLI, an agent, or a desktop app — something with no domain of its own? Read Local applications, which covers the loopback tier and dfos login as a worked example. Once dfos login has minted a credential, dfos api call uses it against any host that advertises API-AUTH, api.dfos.com included — see the CLI documentation. Building an agent integration for someone's whole account? Start with Agents & connected apps. Verifying identity or authorship yourself? See Relays & verification. Unsure what a word means? The glossary defines each one once.

The two meet: public posts, profiles, and spaces come back from the API with protocol handles pointing at the signed chain behind them, so anything you read here you can check for yourself — Verify a post walks one end to end.