Seal and verify construction & engineering documents
Building certificates, structural calculations, inspection reports, and handover packs that carry their own proof — so a building-control officer, a client, or an insurer can confirm a document is genuine and unaltered. A doctored sign-off or an altered calculation fails on sight.
For contractors, architects, structural & civil engineers, and building-control teams.
Four guarantees, in construction & engineering
The record can't be altered
A changed figure, result, or sign-off fails verification. An inspection pass or a load calculation is provably the one that was issued.
The engineer or firm, named
Every certificate and report names the practice that sealed it, chaining to a published root — a specific certificate, not a signature block anyone can paste.
Fixed at the moment of inspection
The issue date is timestamped on Bitcoin — decisive for the sequence of works, sign-offs, and who certified what, when.
Checked by client, insurer, or building control
Anyone relying on the document confirms it at a permalink — instantly, and free, without a call to the practice.
From your file to a proof anyone can check
The same pipeline every time — the seal and the timestamp travel with the file, so the proof is self-contained.
Seal it in the app — no setup
- 1
Sign in as your firm
Open app.letsseal.org and sign in. Your practice gets its own certificate authority the first time you seal — every certificate you issue chains to it.
- 2
Upload the certificate or report
Drop in the signed-off document. It's sealed with your certificate as a PAdES signature over the whole file, so any later edit is caught.
- 3
Anchored and logged automatically
The fingerprint is timestamped on Bitcoin and written to the public transparency log. You get back a normal PDF that also verifies.
- 4
Issue with a proof link
Every document has a permanent proof page. Put the link in the handover pack; the client or insurer opens it to confirm the record is genuine and unaltered.
Automate it from your terminal or CI
The sealbot CLI does the same thing, scriptably — one command per file, straight into your pipeline.
# Seal every inspection report as it's signed off $ sealbot watch /srv/site-reports --mode seal --org examples watching /srv/site-reports … sealing new & changed PDFs (idempotent) # Seal a completion certificate under your firm $ sealbot seal completion-certificate.pdf --org examples sealed completion-certificate.pdf proof https://letsseal.org/d/8b21af…40c3 # A client or insurer confirms it — public, no account $ sealbot verify completion-certificate.pdf ✓ authentic · unaltered · sealed by Let's Seal Examples
Point a watched folder at your document control and every certificate and report leaves already sealed, timestamped, and carrying a proof link — one command per file, no per-seal fee.
What a proof looks like, and what you can seal
- Document
- A sealed completion certificate
- Issuer
- Let’s Seal Examplesletsseal.org
- SHA-256
- 64-hex fingerprint ✓
Anchored on Bitcoin
Recorded in the public transparency log
A single use case, many documents. Each of these is sealed the same way:
A sealed completion certificate
Live proofOpen the proof page the way building control or an insurer would: it shows the certificate is authentic, unaltered since issue, sealed by the named firm, and timestamped on Bitcoin.
A set of structural calculations
Seal the calculations pack so a checking engineer or client can confirm the figures are exactly as issued — an altered load or span is caught instantly.
An inspection or test report
Site inspections and material tests sealed the moment they're signed off: provably the version filed, timestamped, and attributable to the inspector.
An as-built drawing or handover pack
Seal the final drawings and O&M pack so the record handed over at practical completion can be verified as genuine for the life of the building.
Live proofs are real documents sealed under the “Let’s Seal Examples” organisation.
What you’ll seal
- Building & completion certificates
- Structural calculations
- Inspection & test reports
- As-built drawings
- Handover / O&M packs
- Method statements & RAMS
Straight answers
- Does this replace building-control sign-off?
- No. It's the cryptographic layer beneath it: the seal proves the certificate is authentic, unaltered, issued by your firm, and fixed in time. The professional sign-off is still yours — the seal just makes it tamper-evident and independently checkable.
- How does an insurer or client verify a certificate?
- They open the proof link, or drop the PDF into the public verifier. It confirms the document is genuine, unaltered, and issued by you — with no call to your practice.
- Will it still verify years later, for a warranty claim?
- Yes. The seal and the Bitcoin anchor outlive any single vendor, so a certificate sealed today stays independently verifiable for the life of the building.
- Does the recipient need special software?
- No. They get a normal PDF that opens anywhere, and it also verifies against the public portal and any standard PAdES validator.
Start sealing construction & engineering documents
Free and open. Seal in the app, automate from the CLI, and hand anyone a proof they can verify themselves.