API terms

Short version: the sandbox is free and returns one fixed sample home. Real bills cost what the pricing table says. We do not keep the bill images you send us, we never train on your customers’ data and we never sell it. Stay inside the published limits, and tell us before you need more.

Version 2026-08-12. These terms cover the Joulely bill-engine API and sit alongside our terms of service and privacy notice, which apply in full and are not repeated here.

• What the API is — and is not. It reads a UK energy bill and returns structured figures, audited against real tariff data. It is not a smart-meter consumption feed: we are not a DCC “Other User” and we do not supply meter data. If that is what you need you want Hildebrand or n3rgy, and we will introduce you.
• The sandbox. The published key jly_sbx_demo is free, needs no account and always returns the same fixed sample home whatever you send — your request body is not read and no bill is processed. It is limited per IP, because everybody shares that key. Do not build anything that depends on those figures being real: they are one invented home, published so you can see the shape of a response.
• Limits, and what happens at the edge. Your allowance and burst limit are on the developers page and in the X-Quota-* headers of every response — read those rather than guessing. Going over returns a 429, not a surprise invoice: we will never bill you for overage you did not agree to in advance. Sustained abuse, working around the limits, or publishing a key can get it suspended — and wherever we reasonably can, we will tell you why first.
• The bills you send us. We process one to answer your call and then the image is gone — we do not store bill images. We do not use your data, or your customers’ data, to train models, and we never sell it or share it for anyone’s marketing. You keep everything you send; we claim no rights over it beyond doing the job you asked for.
• If the data belongs to your customers. Then you are the controller and we are your processor under UK GDPR Article 28. Our data processing agreement covers that processing — what it says, and how to get a copy, are on that page. Signing it before you build is easier than retrofitting it after something has gone wrong.
• Accuracy, plainly. Our figures are careful estimates built from published tariff data and what the bill says. They are not a bill, not a quotation and not financial advice. If you show them to your own customers, say so. We publish our sources — and still, check before you act.
• Changes. We will give you reasonable notice of a breaking API change or a price change, and neither will be applied retroactively. The version and date at the top of this page is the one you agreed to, and we keep a record of which version that was.
• Ending it. Stop whenever you like. Billing is monthly in arrears, so nothing is paid in advance and there is nothing to refund — you get one final invoice covering the month you stopped in, and nothing after it. We can end it too, on reasonable notice, except where something is being abused or is unlawful. Liability follows our terms of service.

Written to be read by the person doing the integration, not only by their lawyer. If something here would stop you building, say so at business@joulely.co.uk — the wording gets fixed.

Joulely is a trading name of Savernake Technology Limited, registered in England and Wales, company number 09196590. Registered office: C/O Coles Accounting, Office 6, Unit 1a, Solopark Trading Estate, Station Road, Pampisford, Cambridge CB22 3HB.

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