Codecov

Code coverage service that measures test coverage and surfaces insights in pull requests and dashboards. It integrates with major CI platforms and code hosts to track coverage over time and flag untested or risky changes before they reach production.

Codecov goes beyond raw coverage metrics by offering diff coverage for changed lines, flaky test detection, and JavaScript bundle analysis. Part of the Sentry ecosystem, it helps teams like Axle Health cut engineering time spent on broken builds. Supports over 30 languages and 15-plus CI systems, including GitHub Actions, GitLab CI, CircleCI, and Jenkins.

Key capabilities:

• Coverage upload and reporting for any language and CI tool
• Diff coverage to focus on new and modified lines in each PR
• Flaky and failing test tracking with stack traces and re-run support
• Bundle analysis with size limits and status checks to block merges
• Coverage gates and customizable thresholds per project or org
• PR comments and Chrome extension for inline coverage review

Developers use Codecov to meet coverage goals, enforce quality gates, and debug flaky tests without leaving their workflow. The fire-and-forget upload model and server-side merging simplify setup for monorepos and advanced CI configurations.