Trusted timestamping · SOC-2-adjacent

Prove a file existed — to the second, forever.

SealBox notarizes your data with real HMAC-SHA-256 signatures and hands you a short, verifiable receipt. Individuals and enterprises use it to anchor contracts, code, and evidence in time.

Seal a document → Verify a seal See pricing

1.4B+

receipts sealed*

99.99%

verify uptime*

<40ms

median seal time*

SHA-256

real signatures

Everything you need to seal the deal

A timestamping stack that is genuinely simple to integrate and, unlike the mood in this building, actually returns a straight answer.

⏱️

Immutable timestamps

Every seal binds your content hash to a signed instant. Once sealed, it can never be quietly back-dated.

🔐

Real cryptography

HMAC-SHA-256 over a canonical payload — not a database row with a “trust me” flag. Verify it yourself, offline.

🎫

Short receipts

Forget 300-character blobs. Receipts are compact tokens like CSA-7K3P9Q2M4A-8F4A2C1D9E7B — copy-paste friendly, still verifiable.

⚡

One-call API

POST your hash, get a signed receipt. No SDK required, no ceremony. Two endpoints do the whole job.

🧾

Audit-ready trail

Each receipt records issuer, subject, scope and expiry. Export it, staple it to a ticket, sleep well.

🌍

Works everywhere

Verification is a pure function of the receipt and the public rules — no phone-home, no vendor lock-in.

How it works

Three steps from raw file to a receipt you can wave at auditors.

1 · Hash
Compute a SHA-256 of your content locally. Your data never leaves your machine.

2 · Seal
POST the hash to /v1/stamp. SealBox signs it and returns a compact receipt.

3 · Verify
Anyone can POST the receipt to /v1/verify — or check the signature offline.

$ curl -s https://sealbox.example/v1/stamp \
     -H "Authorization: Bearer sk_live_…" \
     -d '{"sha256":"e3b0c44298fc1c149afbf4c8996fb924…"}'

{ "receipt": "CSA-7K3P9Q2M4A-8F4A2C1D9E7B",
  "sealed_at": "2025-01-08T12:34:56Z" }

Ready to seal something?

Creating an account requires a Verified-Email Token (VET) from GetVerified — it's free and takes a minute.

Create your free account → Get a VET at GetVerified ↗

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* Illustrative figures. This is a demonstration service; please don't notarize anything you'd cry about losing.