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 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 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.
API development connects your website, mobile app, and business systems so they share data in real time. UK businesses typically spend £5,000–£40,000+ on custom API builds. Launchwork Digital delivers REST and GraphQL APIs with OAuth authentication, OpenAPI documentation, rate limiting, and full test coverage — typically in 4–12 weeks with fixed-price quotes.
Key Features
What you get when you work with us on your api development project.
RESTful APIs
Well-structured REST APIs following industry best practices and standards.
GraphQL
Flexible, efficient data fetching with GraphQL schemas tailored to your needs.
Authentication & Security
OAuth, JWT, and API key management for secure access control.
Documentation
Comprehensive API documentation with interactive examples and SDKs.
Third-Party Integrations
Connect your systems with payment providers, CRMs, ERPs, and more.
Technologies We Use
Explore Our Insights
In-depth articles related to api development.
Ready to Start Your API Development Project?
Let's discuss your requirements and create something amazing together. Get a free consultation and detailed quote within 24 hours.
Frequently Asked Questions
Common questions about our api development services.
What's the difference between REST and GraphQL APIs?
REST uses multiple endpoints (GET /users, GET /orders) and is simpler to implement. GraphQL uses a single endpoint where clients request exactly what they need, reducing over-fetching. We recommend REST for simpler integrations and GraphQL for complex frontends with varying data needs.
How do you secure APIs against attacks?
We implement authentication (OAuth 2.0, JWT), rate limiting, input validation, encryption (TLS), and monitoring for suspicious patterns. We also follow OWASP API security guidelines and conduct security testing before launch.
Can you integrate with our existing systems and third-party services?
Yes, integration is our specialty. We've connected systems with Salesforce, HubSpot, SAP, Xero, payment providers, shipping APIs, and hundreds of other services. We document all integrations and provide ongoing support.
Do you provide API documentation?
Every API we build includes comprehensive documentation with interactive examples (Swagger/OpenAPI), authentication guides, error reference, and sample code in multiple languages. Good documentation makes your API a pleasure to use.
How long does it take to build a custom API?
A simple internal REST API with 5–10 endpoints takes 2–4 weeks. A typical business API with authentication, rate limiting, and third-party integrations is 4–8 weeks. Complex APIs with GraphQL schemas, real-time subscriptions, and multi-tenant architecture run 8–14 weeks. We work in 2-week sprints so you see and test endpoints continuously rather than waiting for a single launch.
Do you build webhooks and event-driven integrations?
Yes — webhooks are a core part of most modern APIs we ship. We build outbound webhook delivery (with retries, signed payloads, and replay queues), inbound webhook receivers from Stripe, GitHub, HubSpot, Shopify, and others, plus event-driven architectures using AWS EventBridge, Google Pub/Sub, or self-hosted RabbitMQ where the workload demands it. We document every event payload in OpenAPI.
How much does API development cost in the UK?
API development in the UK typically costs £5,000–£15,000 for simple integrations (single third-party service, standard authentication), £15,000–£40,000 for complex APIs (custom data models, multiple integrations, high availability requirements), and £40,000+ for enterprise-scale systems with microservices architecture. Most straightforward REST APIs connecting a website to a CRM or payment processor fall in the £8,000–£20,000 range. We provide fixed-price quotes after a free scoping call.
How long does API development take?
Simple API integrations (connecting a website to Stripe, Mailchimp, or a standard CRM) take 2–4 weeks. Custom REST APIs with authentication, rate limiting, and documentation take 4–8 weeks. Complex systems with GraphQL schemas, multiple integrations, or microservices take 8–16 weeks. We deliver in iterative sprints with weekly demos so you can review progress throughout.
Do you integrate with Salesforce, HubSpot, or Xero?
Yes. We regularly build integrations with Salesforce, HubSpot, Xero, QuickBooks, Stripe, PayPal, Shopify, WooCommerce, and custom legacy systems. Integration work typically involves either using the platform's REST API or webhooks, building middleware to translate data formats, and handling authentication (OAuth flows for most modern platforms). We document every integration so your team understands how data flows between systems.
REST or GraphQL — which should I choose?
REST is the right choice for most UK businesses: simpler to implement, easier to debug, well-supported by every platform, and sufficient for the majority of integrations. GraphQL is worth the added complexity when you have a frontend that needs to query very different data shapes (e.g., a mobile app and a web dashboard pulling from the same API with different field requirements). We'll recommend the right approach after understanding your use case.
What documentation do you provide with the API?
Every API we deliver includes an OpenAPI (Swagger) specification, an interactive Postman collection, authentication setup instructions, and environment variable documentation. For public APIs, we also provide a developer portal with code examples in JavaScript, Python, and cURL. Documentation is not an afterthought — it's part of the delivery definition.