API Developer Salary UK 2026
Last updated: June 2026 • 7 min read • Written by: ClickMasters HR Team • Reviewed by: Reviewed annually
Direct Answer
API Developer salaries from GBP28,000-GBP48,000 to GBP780-GBP1,150/day. NHS FHIR R4 UK Core integration in production (PDS, GP Connect, EPS on NHS Digital developer portal) commands highest NHS premium. FCA Open Banking in production (TrueLayer AISP and GoCardless PISP -- OAuth 2.0 PKCE, consent management, 90-day token refresh) commands FinTech premium. GraphQL federation (Apollo Federation -- multiple teams owning subgraphs) commands enterprise premium.
Market Outlook
API Developers design, build, and maintain REST and GraphQL APIs. In 2026 UK API development has matured significantly: OpenAPI 3.0 is universal, API-first design is standard for UK regulated sectors (NHS FHIR R4, FCA Open Banking, GDS), and API security is a first-class concern. The API Developer role increasingly overlaps with platform engineering.
Salary benchmarks by Seniority
IR35 Tax Position
Day rates assume outside IR35. Inside IR35 contractor day rates in the UK are typically 15–25% higher to compensate for the lack of tax efficiency and additional payroll costs. ClickMasters engineers are directly employed by us, representing **zero IR35 risk** for clients.
Frequently Asked Questions
Everything you need to know about api developer salary standards.
Approximately GBP82,000-GBP130,000 mid-level. London +20-30%.
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