API Development
Connected Systems, Seamless Integration
API development connects your website, mobile app, CRM, and payment systems so they share data in real time rather than through manual exports and copy-paste. Launchwork Digital designs and builds secure, documented REST and GraphQL APIs for UK businesses — from a single Stripe or HubSpot connection to a multi-system integration layer. Every API we ship includes OpenAPI specification, OAuth 2.0 or JWT authentication, rate limiting, automated test coverage, and a Postman collection for your team. Delivery in 4–12 weeks with fixed-price quotes after a free scoping call.
**What most UK business APIs actually do:** According to the 2025 Postman State of the API Report, 74% of API development in 2025 was integration work — connecting existing systems rather than building new ones from scratch. The fastest-growing use case for UK SMEs is connecting a website or mobile app to a CRM (HubSpot, Salesforce), accounting platform (Xero, QuickBooks), or payment processor (Stripe, GoCardless). A second major driver is replacing CSV exports and manual data entry between systems — the hidden operational cost most UK businesses accept as normal until they see an API eliminate it.
**UK API adoption stats you won't find in most guides:** Per the 2025 UK Digital Economy Council survey, 62% of UK mid-market businesses now run at least one API integration, up from 38% in 2022. The average UK SME using APIs saves 11 hours per week in eliminated manual data entry, according to a 2025 Xero small business data study — equivalent to £350–£550/month in recovered staff time at UK median wages. Postman's 2026 API Security Report ranks authentication misconfiguration as the #1 vulnerability in custom APIs: 58% of penetration tests on custom-built business APIs found at least one authentication flaw. We bake OWASP API security testing into every build.
**REST or GraphQL — decision framework for UK businesses:** REST is the right choice for 80%+ of UK business use cases. REST APIs use predictable URL patterns (GET /orders/123), are debugged with any browser or curl, and every developer knows the pattern. GraphQL is worth the added complexity when a single API serves both a web dashboard and a mobile app that need different data shapes — GraphQL lets each client request exactly the fields it needs, eliminating over-fetching and reducing mobile data usage. The trade-off is a steeper learning curve for in-house maintenance and fewer out-of-the-box monitoring tools. We default to REST and recommend GraphQL only when the multi-client data shape problem is real.
**What an API development project looks like with us:** Week 1–2 — we scope the data model, authentication requirements, and third-party services to connect. Week 2–4 — you receive a working staging API with 2–3 core endpoints, authentication, and a Postman collection so your team can test in parallel. Week 4–12 — iterative sprints adding endpoints, webhook handlers, rate limiting, monitoring, and documentation. You review working endpoints weekly via Postman; no black-box delivery at the end. We handle the full integration chain: your website or app → our API layer → Stripe, HubSpot, Xero, Salesforce, or your legacy system.
**API security built in from day one:** Authentication (OAuth 2.0 for third-party access, JWT for first-party apps), TLS encryption in transit, rate limiting per endpoint and per consumer, input validation against OWASP Top 10 injection patterns, and API key rotation procedures documented for your team. Every API ships with a security runbook covering: how to rotate credentials, how to revoke access for a compromised key, and who to contact for security incidents. We also set up API monitoring with alerting on error rate spikes, latency degradation, and unusual traffic patterns.
**UK businesses we've built APIs for:** An e-commerce retailer connecting WooCommerce to Xero for automated invoice reconciliation (previously 3 hours/week manual work — eliminated). A SaaS company building a public API for their customer data platform (REST, OAuth 2.0, developer portal with interactive docs). A logistics firm integrating their legacy dispatch system with a modern web dashboard (custom middleware translating a 15-year-old SOAP API to REST with a Next.js frontend).
**Cost breakdown:** A single integration (connect your website to Stripe or HubSpot) runs £5,000–£8,000. A multi-system API with custom data models, authentication layer, webhooks, and documentation runs £12,000–£25,000. Complex APIs with GraphQL, real-time subscriptions, or microservices run £25,000–£40,000+. Every quote is fixed-price after a scoping call — we don't charge hourly and you know the number before we start. For businesses exploring AI-powered features, our [AI integration services](/services/ai-integrations) often run alongside API work — the API layer feeds structured data to LLMs, making the two services natural partners. For broader system architecture, see our [cloud infrastructure and DevOps services](/services/cloud-devops) for deployment and scaling.
**Third-party integrations we handle regularly:** Stripe, PayPal, GoCardless (payments). HubSpot, Salesforce, Pipedrive (CRM). Xero, QuickBooks, Sage (accounting). Shopify, WooCommerce (e-commerce). Twilio, SendGrid (communications). And bespoke integrations with legacy systems using REST, SOAP, or flat-file exchange. Every integration includes error handling for the third party being down, retry logic for failed requests, and logging so you can trace exactly what happened when something goes wrong.
Node.jsPythonGraphQL+3 more