The same proof you see here, programmable.
ExistBefore is the public showcase of the CertiSigma API. The hash you generate in your browser is attested by the same pipeline you can call directly from your code: T0 ECDSA in milliseconds, T1 qualified timestamp under eIDAS Art. 41 within ~1 hour, T2 Bitcoin anchoring within 24–48 hours.
No card required. The free tier gives you one attestation every few minutes from your IP — the same rate ExistBefore enforces here.
Three tiers, one pipeline.
| Tier | Free (this site) | Developer API key | Enterprise contract |
|---|---|---|---|
| Cost | €0 | Pay-as-you-go | Volume contract |
| Rate limit | ~1/min per IP | Configurable | SLA-backed |
| T0 ECDSA | Yes | Yes | Yes |
| T1 eIDAS TSA | Yes (~1h) | Yes (~1h) | Yes, with SLA |
| T2 Bitcoin | Yes (~24–48h) | Yes (~24–48h) | Yes, with SLA |
| Webhooks | — | Yes | Yes |
| Dedicated keys | — | Yes | Yes (per env) |
| Custom SLAs | — | — | Yes |
| Sign-up | Use the free site | Self-serve key | Contact sales |
What the API actually does.
Three endpoints cover the full pipeline. The body is always a JSON object, the response is always JSON, and the API key lives in the Authorization header — never in a URL.
POST /attest # body: { "hash_hex": "<64-char hex>" }
POST /verify # body: { "hash_hex": "<64-char hex>" } (public, no key)
GET /attestation/{id}/status # T0/T1/T2 progression
GET /attestation/{id}/evidence # raw signed payload + Merkle inclusion proof
GET /keys/{id} # signing public key (JWK)SDKs available for Python, JavaScript / Node, Go and PHP. The Census CLI wraps the same endpoints for shell pipelines.
Try the same pipeline interactively — your file never leaves your browser, only the SHA-256 hash transits via the proxy.
Why this stack matters.
- Cryptographically independent verification. The signed payload, signature, and public key let any third party — including auditors and courts — reproduce the proof without trusting CertiSigma.
- Legal value (T1). Qualified timestamps from accredited TSAs carry full legal force under eIDAS Art. 41 (Regulation EU 910/2014).
- Decentralized permanence (T2). Bitcoin anchoring through OpenTimestamps survives the disappearance of any single operator — including CertiSigma itself.
- Privacy by construction. The API only sees a 32-byte SHA-256. No content, no metadata, no PII.
- Same pipeline, same proof. Whatever you generate from your own code is bit-identical in semantics to what ExistBefore produces.
FAQ
Is the free tier really free? Yes — ExistBefore is operated by CertiSigma as the public funnel for the API. There is no card, no account, no tracker.
Where does the API key live? On your servers. The CertiSigma key is server-side only; client browsers never see it. The same model is used by ExistBefore here (proxy-injected key).
Can I migrate proofs generated on this site into my account? Yes. Every attestation has a public ID and is independently verifiable via POST /verify regardless of which key originally signed it.
Is there a self-hosted option? The signing infrastructure is operated by CertiSigma to keep the trust root small. The verification path is fully open and runs anywhere — your code never depends on CertiSigma being online once you've fetched the public key and the signed payload.