lemma api

Models change. Proofs remain.

Raw data never leaves. Only the proof is sent.

The Lemma API issues five proofs — provenance, authentication, authority, inference, and attribute. Prove without handing over raw data, and verification is always free.

Standards MCPA2Ax402C2PAW3C VC
Five proofs

Five kinds of proof, one API.

  1. 01 来歴 · Provenance Prove origin without handing over the original. Prove where data came from and that it's untampered — without exposing the contents. Poseidon · BBS+ Learn more →
  2. 02 認証 · Authentication Prove identity without sending a key. Prove who you are without ever sending a key. ZK Sign-in · Groth16 Learn more →
  3. 03 権限 · Authority Delegate authority without handing over a key. Build delegation that runs at full speed in scope and stops outside it. Groth16 · EIP-3009 Learn more →
  4. 04 推論 · Inference Prove inference without disclosing the model. Independently verify the consistency of an AI's inputs and behavior. Groth16 · Circom Learn more →
  5. 05 属性 · Attribute Prove you meet a requirement without revealing the attribute. Prove regulated attributes selectively — without handing over the original. BBS+ Selective Learn more →

Issuance is billed; verification is always free. Each proof's detail is on its own page (authentication → Seal).

AI workflow

Trust across every phase.

Keep your AI workflow as-is. Add the Lemma API as one layer, and proof rides every phase — from input to delegated action.

Authentication (identity) applies across every phase.

Integration

One middleware layer in your existing flow.

One SDK. It rides the standards you already use; issuance is metered over x402, verification is public and free.

  1. 01 Mint a key Issue an API key in the Dashboard. Dashboard
  2. 02 Issue a proof Issue from the SDK — settled per issuance via x402, or on a monthly allowance. SDK · x402
  3. 03 Verification is free Anyone, anywhere confirms it — with no raw data. public · free
Standards: MCP · A2A · x402 · C2PA · W3C VC

It rides your existing flow as one middleware layer. Endpoints and code samples are in the specs. This page never calls the API.

How it works

Data stays in place.
Only proofs travel.

The source mints a proof, only the necessary parts are selectively disclosed, and a verifier checks them with a public key. Through all three phases, raw data never moves.

Phase 01 · Issue

Mint the proof at the source

Embed the Lemma SDK at the source. Issue attribute proofs for data, models, and authority. Raw data never leaves.

BBS+ Signature
Poseidon Hash
DID / VC (W3C)
Phase 02 · Prove

Reveal just enough

Selectively disclose only the facts a verifier needs — authority, attribute, integrity. Raw data is never touched.

Groth16 / BN254
Circom 2.x Circuit
Selective Disclosure
Phase 03 · Verify

Anyone can confirm

Anyone, anytime, verifies authenticity with a public key. Optionally anchor as tamper-evident audit attestations.

Public verify (no trust)
EIP-712 attestation
audit anchor (optional)
ZK Groth16 / BN254
Signing BBS+ / EdDSA
Hash Poseidon / Keccak
Identifier W3C DID/VC
Audit anchor EIP-712 / x402
Read the technical spec →

Proprietary cryptography,
three cores.

Three core technologies make the trust infrastructure work — establishing “it’s the same thing,” “disclose only this,” and “no one can rewrite it,” all without touching the original data.

Zero-Knowledge
Proof
Zero-Knowledge Proof

Turn business rules like “18 or older” or “revenue over threshold” into machine-verifiable cryptographic facts. Prove a statement’s truth without touching the original.

Lemma’s edge
Each proof is recorded permanently with its circuit (Circom) and generator, so a third party can reproduce it later.
Read the technical docs →
core of delegate without sharing
Selective
Disclosure
Selective Disclosure

Keeping the binding to the original issuer signature, the holder reveals only the attributes a model needs. Minimize what AI receives as input.

Lemma’s edge
From one issued credential, vary the disclosure per counterparty and use. Hide / Reveal stays controllable after issuance.
Read the technical docs →
core of disclose selectively
On-chain
Provenance
On-chain Provenance

Anchor the document commitment, schema, issuer, and ZK verification result on-chain. Fix it as provenance that can be neither rewritten nor erased.

Lemma’s edge
Only the docHash and CID are public; the body stays AES-GCM encrypted. Keep provenance without exposing the contents.
Read the technical docs →
core of prove after the fact
Pricing

Issuance is billed; verification is free.

You pay to issue; verification is always free. Beyond usage-based billing with no monthly fee, flat-rate quota / grade plans are coming soon. On-chain permanence is optional.

See pricing on /pricing →

Authentication is this API's authentication suite (Seal is its landing page). Trust402 is the wrapper for using this API self-serve (Pay / Sell).

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Models change. Proofs remain.

For enterprises

We configure it to your operations.