Certificates, invoices, payments, contacts, reminders and gas rate calculations in one beautifully simple app. Built for gas engineers who would rather be finished than filling in forms.
Good afternoon
Kabbo Hasan
Outstanding
£1,284.00
4 invoices
This month
18
certificates
Landlord CP12 · 42 Elm Road
Everything in one place
Gas Checker follows the way you actually work - from the first phone call to the final payment.
Domestic, commercial, warning notices, servicing records and continuation pages - ready to complete on site.
A shared calendar for jobs, landlord visits and follow-ups with overdue reminders that shout louder.
Build a quote, convert it to an invoice, record cash, card, bank or iZettle payments in seconds.
Metric and imperial gas rate calculations with gross and net kW - saved to your history.
Keep landlords, agents and installations together with full address and contact history.
Download a full JSON backup or store it securely in your own Supabase project anytime.
Up and running in minutes
Landlord CP12
42 Elm Road · Today 14:00
Boiler service invoice
Mrs Patel · Due in 3 days
Gas rate check
22.4 kW gross · saved yesterday
Reminder: overdue invoice
INV-0032 · £240.00
Simple pricing
Every new account gets 30 days of Professional free. No card required, cancel anytime.
For sole gas engineers getting started.
or £99.00/year · save 17%
Everything a growing heating business needs.
or £199.00/year · save 17%
For teams of engineers and office staff.
or £349.00/year · save 17%
For teams building Flutter apps
Every screen in Gas Checker is powered by a versioned JSON API with bearer-token auth, refresh tokens and subscription gating. Point your Flutter client at /api/v1 and ship.