SLO (Service Level Objective)
An internal reliability target for a service that defines the desired level of performance, typically more stringent than the external SLA, used to guide engineering priorities and error budget decisions.
SLOs are internal goals that set the standard for service reliability. While SLAs are external commitments with financial consequences, SLOs are internal targets that engineering teams use to balance reliability work against feature development. An SLO of 99.95% uptime with an SLA of 99.9% means the team has a 0.05% error budget to spend on deployments, experiments, and migrations.
The error budget concept is powerful. If your SLO is 99.95% monthly uptime and you have consumed only 0.01% of your error budget, the team has room for risky deployments and experiments. If the error budget is nearly exhausted, the team should focus on reliability improvements rather than new features.
Google's SRE practices popularized SLOs as a framework for making objective decisions about reliability investment. For AI products, SLOs should cover both traditional metrics (availability, latency) and AI-specific metrics (model accuracy, response quality). An SLO like "95% of AI responses rated helpful by users" creates accountability for model quality alongside infrastructure reliability.
Related Terms
A/B Testing
A controlled experiment comparing two or more variants to determine which performs better on a defined metric, using statistical methods to ensure reliable results.
Feature Flag
A software mechanism that enables or disables features at runtime without deploying new code, used for gradual rollouts, A/B testing, and targeting specific user segments.
MLOps
The set of practices combining machine learning, DevOps, and data engineering to reliably deploy, monitor, and maintain ML models in production.
Model Serving
The infrastructure and systems that host trained ML models and handle inference requests in production, optimizing for latency, throughput, and cost.
Semantic Search
Search that understands the meaning and intent behind a query rather than just matching keywords, typically powered by embedding-based similarity comparison.
CI/CD (Continuous Integration / Continuous Deployment)
An automated software practice where code changes are continuously integrated into a shared repository, tested, and deployed to production, reducing manual intervention and accelerating delivery cycles.