The invoice app for UK gas engineers.
Voice note in. Branded PDF invoice out — 15 seconds. Gas Safe number printed. Landlord certs, boiler services, tax — all through WhatsApp.
£29.99/mo · 7 days free · no card needed
Start Free on WhatsAppTry it in your head. A real gas engineer’s voice note:
“Boiler service Mr Khan, one-twenty plus parts forty-five for the gas valve.”
Gas Safe registration is not optional — working on gas without it is a criminal offence under the Gas Safety (Installation and Use) Regulations 1998. Your Gas Safe number belongs on every invoice, every CP12, every install certificate. Holdfort prints it automatically so you never forget.
Common gas engineers jobs on Holdfort
Annual landlord gas safety checks (CP12)
Say "CP12 for [address]" and you get a landlord-compliant PDF with appliance records, tightness test result, and Gas Safe number footer.
Boiler services and repairs
Parts (gas valves, pumps, PCBs, flues) captured as line items with batch numbers from a receipt photo. All traceable for warranty.
New boiler installs with Benchmark
Benchmark logbook reference printed on the invoice, manufacturer warranty registration date captured, all in one WhatsApp message.
Commercial and catering gas
CP42 commercial gas safety records issued as PDFs, with the relevant CoNGU work categories referenced as needed.
How gas engineers actually use it day-to-day
The Gas Safe register requires you to give the customer a gas safety record within 28 days and the landlord a copy within 28 days for rental properties. Traditionally that’s: paper triplicate book in the van, give one copy on site, post the other or scan and email later. Miss a deadline, you’re in breach. Holdfort’s CP12 flow means you hand the customer the PDF before leaving site — they get it on WhatsApp or email within seconds — and your own copy is automatically archived in your chat history. For multi-landlord engineers running 400+ CP12s a year, it’s the difference between a January compliance scramble and never thinking about it.
Questions gas engineers ask us
Yes. Register it once (voice note it or snap a photo of your card) and every PDF from then on has your Gas Safe number printed in the footer — invoices, CP12s, quotes, variations, everything. It’s also on the footer of any follow-up PDFs you generate months later.
Yes. Say "CP12 for 47 High Street, Bristol" and you’ll get a CP12-format PDF back. If any of the tenancy or appliance details are missing Holdfort will prompt for them. Once complete, the PDF is ready to forward to the landlord or letting agent, complete with your Gas Safe number, appliance record, and tightness test result.
The Benchmark reference prints on the install invoice as a line item. The logbook itself is still the manufacturer’s job (you tick through the pages on their portal or the physical booklet), but the invoice provides the paper trail linking the benchmark record to the customer record.
Same flow, different PDF template. Voice-note "CP42 for [venue]" and the resulting document has the commercial-specific fields filled. If you’re CoNGU-qualified across categories (CCN1, ICPN1, CESP1, CORT1, etc.), register them in your profile and they print on the footer alongside your Gas Safe number.
£29.99/month, inc. VAT. 7 days free. No card to start. Founding-member price locked for life. See the pricing page.
No. Holdfort is WhatsApp — the one you already have. There’s nothing to install and no login to remember.
Yes. Quarterly-ready breakdowns, sole-trader categories, no spreadsheets. Ready for MTD for Income Tax from April 2026.
Finish the job. Voice note the details. Invoice done.
7 days free. 30 seconds to set up. Just WhatsApp.
Start Free on WhatsAppHold the fort. We’ve got the paperwork.