Short, honest answers to the questions we get most. If yours isn’t here, email [email protected].

What is Marturia, in one sentence?

Marturia turns each important AI-agent decision into a cryptographic receipt — signed, hash-chained, and verifiable by anyone — so you can later prove what your agent decided and that the record hasn’t been altered.

How is that different from observability tools like LangSmith or Datadog?

Observability is for you — traces, tokens, latency, debugging — and it assumes you trust the data because it’s yours. Marturia is for someone who doesn’t trust you: a regulator, an auditor, an insurer, a counterparty. A trace shows what happened to whoever already trusts the platform; a receipt proves it to a hostile third party. Different jobs — keep your observability stack and add receipts only where disputes would hurt. More in logs aren’t evidence.

What’s actually in a receipt? Do you store my data?

A receipt binds — by hash — the decision payload you choose to include (inputs that drove the decision, the action, the model id), plus a timestamp and a sequence number, signed with your tenant’s key. You decide what goes in the payload; put the decision, not raw context. We store the receipt chain, not your application’s data.

Who holds the signing keys?

Each receipt is signed with an Ed25519 key scoped to your tenant. Keys are isolated per tenant, so one customer’s compromise can’t touch another’s. For the BYOK (bring-your-own-key) model on higher tiers, see the BYOK guide.

Is Marturia built on a blockchain?

No. Receipts are signed and hash-chained off-chain, and a Merkle root is periodically cosigned by an in-house witness — nothing goes on a public ledger. That’s a deliberate choice: it’s cheaper, faster, private, and lets you honor data-erasure requests, none of which a public chain allows. The full reasoning is in why we don’t put audit trails on a blockchain.

How does verification work? Does the verifier need an account?

No account, no API key. Anyone with the receipt and your tenant’s public key runs the open-source verifier locally:

pip install marturia-verify
marturia-verify --receipt receipt.json --pubkey-hex <tenant-public-key>

It checks the signature, walks the hash chain, and confirms the witnessed root — reporting VALID or exactly which check failed.

What happens if Marturia disappears?

The receipts you’ve already collected stay verifiable. Verification needs only the receipt material and your public key, and the verifier is open source — it doesn’t phone home to us. You’re not locked to our uptime for the part that matters.

Can you honor a GDPR right-to-erasure request?

Yes, via a tombstone: replace the payload, preserve the hash that proves the original existed. The chain stays intact and the erased content is gone. This is exactly the thing an immutable public ledger can’t do — see the tombstone-pattern guide.

Does using Marturia make me EU AI Act / ISO 42001 compliant?

No — and anyone who tells you a single tool does is overselling. Marturia covers one dimension: the integrity of the records you keep. It’s not a compliance program, and nothing here is legal advice. How it maps to specific obligations (and what it doesn’t cover) is laid out in the AI Act / ISO 42001 crosswalk.

Is the verifier open source?

Yes. marturia-verify is a public Python package, so customers, auditors, and even skeptics can inspect or re-implement the checks. The point of verifiable evidence is that you don’t have to trust us — you can check the math.

How do I add it to my agent?

One call at the decisions that matter — see how to add receipts to any AI agent (framework-agnostic) or the LangChain integration.

What does it cost, and how do I get access?

Marturia is in closed beta. The public verifier is free to use right now (pip install marturia-verify). For agent-side access during the beta, email [email protected] or start at /docs/quickstart.html.

Related Marturia resources - /guides/instrument-ai-agent-with-receipts.html - /blog/why-we-built-marturia.html - /guides/marturia-vs-langsmith-vs-sigstore.html