Sage Integration Developers UK

First question: which Sage?

"We use Sage" can mean very different things, and the integration route depends entirely on which product:

Part of our free chat is working out exactly which product and version you run, because it changes the design, the cost and the risks.

Integrating Sage Accounting (cloud)

Sage Accounting has a modern REST API. Version 3.1 serves all supported countries from one base URL, https://api.accounting.sage.com/v3.1/, and supports reading and writing contacts, products, sales and purchase invoices, credit notes, payments, ledger accounts and tax rates.

• OAuth 2.0. A user authorises the connection through the authorisation code flow. Access tokens are short-lived, and refresh tokens rotate: each refresh returns a new one and the old one stops working. Lose the new token and the user has to reconnect, so we store it transactionally and encrypted.
• Multiple businesses. One login can access several businesses; each request names the business in an X-Business header.
• UK tax. The API exposes UK tax rates, so each invoice line carries the right VAT treatment. Sage Accounting then handles Making Tax Digital VAT submissions itself.
• Limits. Sage sets request limits per app and concurrency limits, and returns HTTP 429 when they are hit. We queue work and back off, rather than hammering the API.

Integrating Sage 50 Accounts

Sage 50 is still common in UK businesses, especially those with an accountant who has used it for years. It's desktop software, so the website or cloud system can't call it directly over the internet. The usual design is:

1. A small connector service runs on a Windows machine on your network that can open the Sage 50 company data.
2. It uses Sage's Windows SDK to read and post records, such as customers, invoices and payments.
3. It talks outward to your website or cloud system over HTTPS, collecting new orders from a queue and posting results back. No inbound ports are opened in your firewall.

This needs care: Sage 50 versions change, the SDK must match your version, and the machine has to be on when syncs run. We'll be clear about those trade-offs. For some businesses, moving to a cloud package is the better long-term answer, and we can help with the data migration.

What we connect to Sage

• Ecommerce: Shopify, WooCommerce, OpenCart and Magento orders into Sage as invoices or sales receipts, with stock levels flowing back where Sage holds stock. See ecommerce to ERP integration.
• Payments: Stripe and other gateways, posted with fees separated so bank reconciliation works.
• CRM: won deals become invoices; account balances show in the CRM. See CRM integration.
• Bespoke systems: job management, billing and trade portals posting into Sage.

Reliability details we build in

Sage integrations fail in predictable ways, so we design for them from the start. Contacts are matched on a stored Sage ID, not by name, so a renamed customer doesn't become a duplicate. Every invoice carries your own order reference, and we check for it before posting, so a retried job can't create the same invoice twice. Rate-limited or failed requests go back on the queue with increasing delays.

For Sage 50 connectors, the service records what it has processed both locally and on the server, so a PC restart mid-sync picks up where it left off. If the connector hasn't checked in for a set time, you get an alert. Your finance team gets a plain-English log showing every record sent to Sage and its result.

Our process

After the free chat, we confirm your Sage product and version, test access (using a Sage Accounting trial business or a copy of your Sage 50 data, never live books), agree the mapping with your accountant and give you a fixed-price quote. We build, run in parallel with your manual process until the figures match, and hand over the code and documentation. You own it all.

Comparing Sage with Xero or QuickBooks? See accounting software integration and our API integration overview.

What we deliver

• Identification of your exact Sage product and version, and the right integration route for it
• A ledger, VAT and department mapping agreed with your accountant
• Contact, sales invoice, credit note and payment sync
• For Sage 50: a small Windows connector service that talks to Sage locally and to your systems securely
• Token handling, rate-aware queuing and retry logic
• Sync log, alerts and documentation

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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