This work ends with paperwork signed in a corridor. The engineer has the commissioning sheet on a clipboard or a battered tablet, the customer’s facilities manager signs somewhere near the bottom, somebody photographs it, and it goes into the handover pack with the as-fitted drawings and the O&M manual.
That holds up until there is money attached to the question, and on this kind of work there usually is. Three separate things hang off one signature: when the warranty and maintenance period started, which revision of the design was accepted, and what was agreed as extra while the van was still outside.
The four signatures that come back to bite you
- The customer acceptance or commissioning certificate. Your warranty and your maintenance period usually run from it. If the only record is a date somebody wrote in biro, the start date becomes whatever the customer remembers, and it is never remembered in your favour.
- The variation agreed on site. “While you’re here, put a reader on the back door and move that camera off the soffit.” Two hours and a bit of cable, priced verbally in a car park. It gets queried at final account, not on the day.
- The handover pack itself. As-fitted drawings, O&M manual, IP schedule, the system admin handover. Handing it over matters, and so does showing which revision they received, and when.
- Remote access and system administration. You keep a route into the customer’s NVR or door controller so you can support it. The written permission for that, and for who may view recorded footage, is a one-page form nobody can find two years later.
None of those are difficult to produce on the day. All of them are difficult to prove afterwards, and proving is a different job from producing. A photographed sheet shows a mark on a page: not when the mark was made, not whether that sheet is the version you issued, not whether anything changed after. Sent on WhatsApp it is worse again, a cropped and re-encoded copy with the metadata stripped out.
What sending it through Pixasign changes
The job keeps its shape. You send the certificate, the customer’s facilities manager opens it on whatever phone they have to hand, signs, and it comes straight back. No app to install, no account to create: they tap a link in an email. The link stays live for fourteen days, which covers the manager who is only on site on Tuesdays.
What changes is what you are holding afterwards. Pixasign gives each signed PDF a cryptographic seal, and the seal carries an independent timestamp issued by DigiCert.
That second part is the one that counts when a warranty date is argued over. A timestamp is worth nothing if the company being asked about the date is also the company issuing it. DigiCert is an independent timestamp authority, and its attestation that your signed document existed at the moment it was sealed is embedded in the PDF itself, for the customer or their insurer to check.
Alongside the sealed PDF you get an evidence certificate: who signed, the address it went to, their IP and approximate location, the device, the timeline to the second, and digital fingerprints of the file before and after sealing. The events are hash-chained, each one locking in the one before. The chain’s final value is printed on the evidence certificate every party is sent, so a later change to the record would not match their copy.
| The question | Signed sheet, photographed | Sealed through Pixasign |
|---|---|---|
| When did the warranty start? | The date written on the sheet | Recorded to the second, and the sealed document carries a DigiCert timestamp |
| Which drawing revision did they accept? | Whichever one was in the pack | A digital fingerprint of that exact file |
| Who authorised the extra readers? | Someone on site, name half legible | Name, email, IP, device, to the second |
| Has it been altered since? | No way to tell | Change a byte the seal covers and it breaks; anything added later shows as a change at pixasign.co.uk/check |
| Can the customer’s insurer check it? | They have to take your word for it | Anyone can check it, free, without an account |
Technical details
The seal is a PAdES document timestamp, the standard set out in ETSI EN 319 142: an RFC 3161 timestamp issued by DigiCert over the whole file, RSA-4096 with SHA-384, with long-term validation (LTV) data embedded in the PDF. The fingerprints on the evidence certificate are SHA-256 hashes.
Checkable by the customer, their insurer and your inspector
The seal and its timestamp are embedded in the PDF itself, and anyone can check a document free at pixasign.co.uk/check: drop or choose a file and it tells you whether Pixasign sealed it and whether it has changed since. No account, no login, which is the point when the person asking is a loss adjuster or the customer’s new facilities manager.
Download your sealed certificates and handover packs whenever you like. They keep working if you stop being a customer: the seal and its DigiCert timestamp are inside the file, and pixasign.co.uk/check still recognises every file Pixasign sealed. The files live on hardware in Nuremberg, Germany, with encrypted backups in Reykjavík, Iceland, and card payments are handled by Stripe. The detail is on our security page.
Flat pricing, because more than one person sends paperwork
Most e-signature tools charge per user, which is the wrong shape for an install business. The engineer needs a variation signed on site, the project manager sends the acceptance certificate, and whoever is covering the office on Friday sends next year’s maintenance agreement. Per-seat pricing leaves you paying for all of them or sharing one login, and a shared login destroys the audit trail you bought the thing for, because every document goes out from the same account and nobody can show who sent what.
Pixasign is free for 1 user and 3 documents a month, then one flat monthly price with unlimited users: £19 a month for 50 documents, £59 for 200, £99 for 500, all inc VAT. The price you see is the price you pay. Unlimited users means no charge per user: an account starts with room for 200 active people, and we raise that free on request. Put every engineer on it. Your customers never pay and never need an account.
Seal one commissioning certificate
Free for 3 documents a month, no card. Take a certificate from a job you are finishing this week, send it to the actual customer, and look at the evidence certificate that comes back.
Start free UK company. Documents stored in the EEA.Questions
- Will an electronically signed acceptance certificate satisfy our certification body?
- Electronic signatures are valid and enforceable for the vast majority of UK business documents, and a customer acceptance or commissioning certificate is an ordinary commercial record. Inspectorate and certification schemes are a separate question from the law, though, and they set their own rules about the form of documentation they expect to see. Ask whoever handles your scheme compliance before you move a certificate across. That answer should come from them, not from a supplier, ours included.
- The facilities manager is only on site one day a week. Does that break it?
- No. Send it when the engineer finishes, and the link stays live for fourteen days. They can read and sign it from their own office, or from home, on whatever device they have to hand. You are no longer waiting for them and a clipboard to be in the same building at the same time.
- Can an engineer get a variation signed on site, there and then?
- Yes. Send the variation from your computer, or have the office send it, and the customer taps the link on their phone, signs, and the sealed PDF and its evidence certificate exist before you have packed the tools away. Nothing is installed on their phone and they never create an account.
- What happens to our handover packs if we stop paying?
- Nothing is deleted. The account moves to the Free plan, so you can still open, download and check everything already signed, and send up to 3 documents a month. Documents you sent earlier in the same month count towards it. Anything already out for signature still completes. Anything you have already downloaded is unaffected, because the seal and its timestamp are embedded in the PDF itself.