Archive web pages as tamper-evident, signed evidence
A plain screenshot says "trust me." When a price, a disclosure or a contract page is the thing in dispute, you need a capture you can prove wasn't edited. That's signed evidence.
Why a normal screenshot isn't enough
Anyone can open an image in an editor. For audits, content disputes, pricing/TOS change tracking or compliance reviews, a PNG on its own has no chain of integrity — there's nothing that proves it shows what the page actually returned, on the date it claims.
What "signed evidence" means
A signed evidence API returns the artifact plus a canonical manifest carrying:
- the artifact's SHA-256 hash,
- capture metadata (requested URL, final URL after redirects, HTTP status, timestamp, viewport, engine versions),
- an Ed25519 signature over the canonical (sorted-key) manifest.
Change one byte of the manifest and signature verification fails. That's what "tamper-evident" means in practice.
Capture the evidence
curl --request POST \
--url https://screenshot-e-pdf-render.p.rapidapi.com/v1/evidence \
--header 'X-RapidAPI-Key: YOUR_KEY' \
--header 'X-RapidAPI-Host: screenshot-e-pdf-render.p.rapidapi.com' \
--header 'Content-Type: application/json' \
--data '{ "url": "https://example.com/terms", "response_mode": "archive", "quality_profile": "forensic" }' \
--output evidence.zip
The ZIP contains artifact, manifest.json, signature.txt and public-key.json. Use quality_profile: "forensic" for a lossless PNG with no determinism normalisation.
Verify it — offline, without trusting the vendor
The public key is also at GET /v1/meta/evidence-public-key. To verify: recompute the artifact's SHA-256, rebuild the canonical manifest (sorted keys, signature fields removed), and Ed25519-verify against the signature. Open-source verifiers exist in Node, Python and PHP, so verification never depends on the API provider.
A practical compliance workflow
- List your critical pages: pricing, terms, disclosures, promotional claims, regulated landing pages.
- Capture them on a schedule (cron, n8n, a Lambda) and store the ZIPs in your own storage.
- When something changes, run a visual diff between two dates to show what changed.
- Keep your own retention and access policy around the archive.
Honest scope
Signed evidence is a tamper-evident technical capture — a verifiable record of what a page returned at a point in time. It's excellent for internal audit, dispute handling and change management. It is not a turnkey legal or notarial certification; for regulated use, pair it with your own retention, supervision and (where needed) legal review. Avoid "court-proof" claims; "tamper-evident" and "offline-verifiable" are what you can actually stand behind.
Try it
RenderShot's /v1/evidence returns a signed ZIP (or inline JSON), with standard and forensic profiles. Free tier, no card.