Sign in
On first connect your client opens a browser window. Sign in with AffixIO Studio, then choose which API key the client may use on the consent screen. The consent screen shows which app is asking and where it will send you back.
Quickstart
Connect AffixIO and make your first proof in a few minutes.
Add the hosted AffixIO MCP server to your AI client, prove a simple yes/no condition, verify it with a signed ML-DSA-65 attestation, then move to the affixio SDK or API when you are ready to build.
1Connect the hosted MCP server
Most MCP clients that support remote servers only need the URL. Add this to your client's MCP configuration:
{"mcpServers":{"affixio":{"url":"https://www.affix-io.com/mcp/"}}}If your client only supports local (stdio) servers, use the mcp-remote bridge instead:
npx -y mcp-remote https://www.affix-io.com/mcp/
What happens behind it
Your client registers itself (dynamic client registration), completes OAuth 2.1 with PKCE, and receives a token scoped to the key you picked. No API key is pasted into the client. See MCP connection for more detail.
2Make and verify your first proof
Once connected, ask your agent to call these two tools, or call them directly. First, prove the built-in yesno circuit:
affix_circuit_prove
{"circuitId":"yesno","body":{"fields":{"condition_greater1":true,"condition_greater2":true,"condition_greater3":true}}}The response includes a proof ID. Pass it to verify, and ask for an attestation:
affix_circuit_verify
{"circuitId":"yesno","body":{"proof":"<proof_id>","requestAttestation":true}}Good to know. Proofs are single use. Verifying the same proof a second time returns
409 double_spend_detected, which is how AffixIO stops replay. Attestations are signed with ML-DSA-65, a post-quantum signature scheme, so a third party can check the result without seeing the underlying data.3Build with the SDK or API
For application code, install the public Node.js package (Node.js 20 or later, Apache-2.0):
npm install affixio
Keep API keys in a trusted server runtime, never in public browser JavaScript. The API base is https://api.affix-io.com.
| Where next | What you will find |
|---|---|
| AffixIO documentation | SDK setup, verification modes, API references and integration boundaries. |
| Node.js SDK | What the affixio package does and how to configure it. |
| SDK proof modes | HMAC and UltraHonk proof modes and their trust assumptions. |
| Developer entry points | Connecting a trusted application with an API key and the published HTTP schema. |
| Migration to 2.0 | Moving from 1.x package names to affixio 2.0. |
| affixio on npm | Current published version and README. |
4Free proofs
AI agents
150 free proofs, no card needed.
Humans
100 free proofs, no card needed.
Read the details on the free proofs page, or see pricing for paid plans.