QuickBooks Online Integration Developers UK

When a custom QuickBooks integration makes sense

QuickBooks Online has a large app marketplace and plenty of connectors. Use one if it fits. We build custom QuickBooks integrations when your process doesn't fit a generic tool: sales coming from a bespoke system, invoices that need specific classes or locations, multi-company routing, or a need to show live payment status inside your own software.

Typical work includes creating customers, raising invoices or sales receipts with correct items and tax codes, recording payments and refunds, issuing credit memos and pulling back payment status. We've built accounting integrations since our KashFlow and OpenCart days, and the same care goes into the QuickBooks work.

The QuickBooks Online API: what matters technically

• OAuth 2.0 only. There are no API keys. An admin authorises the connection once, and each company is identified by a realm ID.
• Short access tokens, rotating refresh tokens. Access tokens last an hour. When the integration refreshes, Intuit may return a new refresh token, and the integration must save it. Many "it keeps disconnecting" problems come from code that doesn't. Intuit has also moved refresh tokens to a fixed maximum lifetime, so long-running connections will eventually need reauthorising, and we build a reminder in.
• Rate limits. 500 requests per minute per company and 10 concurrent requests, with lower limits on batch and resource-heavy endpoints. The batch endpoint groups up to 30 operations per request.
• Webhooks and Change Data Capture. Intuit sends a webhook when entities change, signed with an HMAC in the intuit-signature header. Payloads are deliberately small, so we follow up with the Change Data Capture (CDC) endpoint to fetch everything that changed since a timestamp.
• Minor versions. Intuit evolves the API through minor versions specified on each request. We pin a version and test before moving.

Intuit's App Partner Program and API costs

Intuit launched its App Partner Program in July 2025, which changed the commercial basis of QuickBooks API access. Calls are split into two kinds:

• Core calls, mostly data going into QuickBooks (creating or updating customers, invoices, payments), are free and unlimited on every tier.
• CorePlus calls, mostly reading and querying data out of QuickBooks, are metered. The free Builder tier includes a monthly allowance, and paid tiers raise it.

This shapes design. An integration that pushes invoices in and only reads back what it must, prompted by webhooks rather than constant polling, will usually sit comfortably in the free tier. One that copies your entire ledger into a reporting database every night may not. We estimate your CorePlus usage during scoping and design to keep it sensible. If you need heavy reporting, we may suggest a different approach, such as a nightly incremental sync using CDC instead of full reads.

UK specifics: VAT and QuickBooks

UK QuickBooks Online companies apply VAT through tax codes and rates set up in the company, and QuickBooks files Making Tax Digital VAT returns directly with HMRC. Our job is to make sure every line arrives with the right tax code, so the return is right without manual correction. We agree the mapping with you and your accountant first, covering standard, reduced, zero-rated, exempt and reverse-charge items, and test it against a QuickBooks sandbox company before going live.

Payments from Stripe or another payment gateway are posted with fees separated out, so deposits match your bank feed.

Common QuickBooks integration patterns

• Ecommerce to QuickBooks: Shopify, WooCommerce or OpenCart orders as invoices or sales receipts, with refunds as credit memos or refund receipts. See Shopify integration.
• CRM to QuickBooks: won deals become invoices, and outstanding balances show to the sales team. See CRM integration.
• Job and field service systems: completed jobs invoiced with the right items and classes.
• Bespoke billing: recurring or usage-based invoices from your own platform, with payment status returned.
• Reporting: incremental extraction of the data your dashboards need, designed around CorePlus metering.

How we deliver

Free chat first. Then a scoping stage using an Intuit sandbox company, so nothing touches your live books, ending in a fixed-price quote. We build and test in the sandbox, connect to your live company, and run in parallel with your current process until the numbers agree. You own the code and documentation.

Not sure QuickBooks is the right package, or connecting more than one system? See accounting software integration, Xero integration and our main API integration page.

What we deliver

• A mapping of items, income accounts, tax codes and classes agreed with your accountant
• OAuth 2.0 connection with secure, rotating token storage
• Customer, invoice, sales receipt, credit memo and payment sync
• Webhook and Change Data Capture handling so changes in QuickBooks flow back
• Call budgeting so data-out usage stays within the free App Partner Program allowance where possible
• Error log, alerts and retry tools for your finance team

How it works and what it costs

Every project gets a fixed-price quote after a free initial chat and a short scoping stage. You own the code and the data.

1. Free chat

   Tell us the problem in plain English: what you do now, what goes wrong and what "better" looks like. No charge, no obligation.

2. Scoping

   We map the processes, systems and data involved, agree what is in and out, and write it down so there are no surprises.

3. Fixed-price quote

   You get a fixed price for the agreed scope, or a phased plan for bigger builds, so you can start small and prove it works.

4. Build and test

   We build in short stages you can see and try, test against real data, then go live carefully with a rollback plan.

5. Hand over and look after

   You own the code and the data. We can host it, support it and keep improving it, or hand it to your own team.

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