Prove what your AI agents actually did.
Every action your agent takes is signed, chained, and witnessed. Anyone can verify a Sequesign receipt offline, even years later.
Tamper-evident
Audit trails that fail loudly.
Every action enters a signed hash chain. Re-ordering, omission, and after-the-fact edits are detectable on verification.
Tampered receipts surface as verification failures, not as a clean log. The verifier tells reviewers exactly which action, which evidence hash, and which chain state broke.
See a tampered receipt fail →Offline verification
Verifiable offline. By anyone.
The verifier needs no Sequesign endpoint to confirm a receipt at verification time. Given the receipt and the witness's published public key, any reviewer can verify the chain, the schemas, the workflow, and the human approval signatures. No network access to Sequesign required at the moment of verification.
View the live witness key →Interactive demo
A delegated agent workflow, verified.
Pick a domain and a condition, then verify. The same Sequesign verifier handles both workflows; the failure modes are real, not staged.
Receipt sandbox
Trust model
What a receipt can and cannot prove.
Sequesign shows what is verified, what is attested, and what remains only agent-asserted. The distinction is the product.
What the receipt can prove
- Evidence has not changed after receipt construction
- Action sequence and chain continuity are intact
- Agent and witness signatures verify
- Schema validation passed, when requested
- Workflow profile validation passed, when requested
- Human approval signature is present and valid
What a receipt does not prove
- The agent told the truth
- The invoice came from the real vendor
- The payment provider confirmed the instruction
- The LLM provider attested to the response
- A lying agent self-reported every unsupported claim
- Every natural-language claim is externally verified
SDK
One SDK call per action.
Start a session. Record actions as they happen. Finalize. The receipt is a single signed artifact reviewers can verify with the local CLI or the hosted verifier when it ships.
- Three receipt modes: freeform, schema-validated, profile-constrained
- Built-in human approvals, plan steps, counterparty attestations
- Cross-process resume from on-disk checkpoint
- Verification levels L0 through L5 reachable from real SDK calls
import { createSequesign } from "@sequesign/sdk"; const sdk = createSequesign({ witness: { baseUrl: "https://witness.sequesign.com", apiKey: process.env.SEQUESIGN_WITNESS_KEY } }); const session = await sdk.startSession({ agent: { agentId: "agent_acme_invoice_bot", keypair: agentKeys }, task: { taskId: "inv_2024_07_421", profile: "invoice-payment-v1" } }); await session.recordAction({ actionType: "invoice_reviewed", evidence: { invoice_id: "inv_2024_07_421", decision: "approve" } }); const { receiptPath } = await session.finalize(); // receiptPath → ./out/<task_id>.tar.gz · verifiable offline
# Python SDK coming soon. # Track progress on GitHub: https://github.com/Sequesign/SequeSign
// Go SDK coming soon. // Track progress on GitHub: https://github.com/Sequesign/SequeSign
Pricing
Choose your trust model.
Start free, pay only for what you sign, or run a dedicated witness. The protocol, the SDK, and the verifier are identical across tiers. Library storage is $0.05 per GB-month on every paid tier; configure retention via pruning policies.
Free
Developer tier
$0 / month
Try the protocol with no commitment.
- 5,000 signatures / month
- 50 MB library storage (auto-pruned at limit)
- Shared witness service
- Email support
Shared
Pay as you go
$0.001 per signature
Bill only for what you sign. Storage at $0.05 / GB-month.
- 1 GB library storage included
- $0.05 per GB-month for additional storage
- Configurable retention (time-based or size-based pruning)
- Shared witness at witness.sequesign.com
- Email support
Managed Isolated
Dedicated witness for your data
For regulated industries$25 / month + $0.002 per signature
Your own dedicated witness instance with isolated keys.
- 10 GB library storage included
- $0.05 per GB-month for additional storage
- Configurable retention (time-based or size-based pruning)
- Dedicated witness instance with isolated keys
- Priority support
Bring Your Own Witness
Run your own infrastructure
For data sovereigntyContact us
Run the witness on your infrastructure. We provide the protocol, SDK, indexing, and support.
- 25 GB library storage included
- $0.05 per GB-month for additional storage
- Witness keys never leave your infrastructure
- Indexing service for receipt library
- Protocol updates and integration support
Enterprise
Custom for your scale
For complex needsCustom
Annual contracts, dedicated support, custom SLA.
- All deployment options
- Custom storage quotas and rates
- Dedicated support engineer
- 99.99% uptime SLA
Use cases
One protocol. Many delegated workflows.
The same sequence-signing receipt pattern applies wherever agents act on behalf of people or organizations. Below are the workflows the protocol was designed against and the ones it's being shaped toward next.
Invoice and procurement approvals
Receipts attach decision evidence and human approval to every payment instruction an agent emits.
Healthcare decision support
Sign clinician confirmations alongside model output for prescription, triage, and intake.
Financial and compliance agents
Per-action receipts that survive audit cycles for trading bots, KYC, and regulated reporting.
Customer operations automation
Refunds, escalations, and entitlement decisions land in a permanent, attestable log.
Get started
Ready to sign your first receipt?
Sequesign issues API keys directly from the dashboard. The hosted witness is live; the SDK is feature-complete; the verifier runs locally today.
IP posture
Patent pending.
Sequesign technology is patent pending. This demo explains protocol concepts and is not a production deployment.