What is SLA? — UK Software Development Guide

4 min readJune 2025ClickMasters Technical TeamReviewed by James Whitmore, CTO
what is an sla software

Direct Answer

An SLA (Service Level Agreement) is a contract between a service provider and a client that defines the expected level of service. In software development and IT services, SLAs typically define: uptime (e.g. 99.9% availability), response times (e.g. P1 incidents acknowledged within 1 hour), resolution times (e.g. critical bugs fixed within 4 hours), and support hours (e.g. 8am–6pm GMT weekdays).

Sla in the UK

SLAs have specific UK legal context. Under UK contract law, SLA breaches give the client remedies including damages for proven losses — making SLA definition and measurement critically important. FCA operational resilience requirements (PS21/3) require firms to define impact tolerances for important business services — SLAs are the technical expression of these tolerances. ClickMasters offers SLA-backed software maintenance retainers with 1-hour P1 response (Priority tier) down to next business day (Essential tier). NHS software suppliers should consider DSP Toolkit Standard 10 (business continuity) when setting SLAs.

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