Codecov From $5/mo · Free plan 9.3 Visit SimpleCov
github.com
What it is
SimpleCov is a free, MIT-licensed tool for measuring Ruby code coverage with Ruby’s built-in Coverage library. It produces HTML and JSON reports and can merge results across test suites. Coverage types include line, branch, method, oneshot-line, and eval. Configuration supports filters, groups, profiles, and thresholds. Optional test tracking can show which RSpec examples or Minitest tests cover a line, while oneshot coverage can record code reached in production. The command line includes report viewing, test selection, patch coverage, history, status, and badge commands. A Rails profile can include ERB, Haml, and Slim templates in reports. SimpleCov can also calculate coverage for changed lines and apply a minimum threshold as a gate. The project says it is built in CI on Ruby 3.2+ and JRuby 10+; JRuby supports line coverage only. To track application files, SimpleCov must start before application code is required. The project directs code and bug reports to its issue tracker and discussion and announcements to its Google Groups mailing list.
Spec sheet
- Purpose
- SimpleCov analyzes Ruby code coverage using Ruby’s built-in Coverage library.Read 30 Sep 2026 · github.com
- Integrations
- The README points to open source formatter and integration plugins, editor integrations, and hosted commercial services.Read 30 Sep 2026 · github.com
- Support
- The project directs users to its issue tracker for code and bug reports and its Google Groups mailing list for discussion and announcements.Read 30 Sep 2026 · github.com
- License
- The repository identifies SimpleCov as MIT licensed.Read 30 Sep 2026 · github.com
- Change coverage
- The CLI can calculate coverage for changed lines and use a minimum threshold as a gate.Read 30 Sep 2026 · github.com
- CLI
- The command line includes report viewing, test selection, patch coverage, history, status, and badge commands.Read 30 Sep 2026 · github.com
- Compatibility
- The project says it is built in CI on Ruby 3.2+ and JRuby 10+; JRuby supports line coverage only.Read 30 Sep 2026 · github.com
- Configuration
- Configuration supports filters, groups, profiles, line and branch coverage, and coverage thresholds.Read 30 Sep 2026 · github.com
- Production usage
- Oneshot coverage can record production code usage for identifying code that tests or live traffic do not touch.Read 30 Sep 2026 · github.com
- Reports
- It includes HTML and JSON formatters and can merge coverage results across test suites.Read 30 Sep 2026 · github.com
- Security and compliance
- The repository page shows a Security and quality section but states no security certification or compliance standard in the README.Read 30 Sep 2026 · github.com
- Setup constraint
- SimpleCov must start before application code is required to track those files.Read 30 Sep 2026 · github.com
- Test mapping
- Opt-in test tracking can show which RSpec examples or Minitest tests cover a line.Read 30 Sep 2026 · github.com
- View templates
- With the Rails profile, it can include ERB, Haml, and Slim templates in coverage reports.Read 30 Sep 2026 · github.com
Plans and prices
SimpleCov Free Ruby code coverage · MIT licensed Read 30 Sep 2026 · github.com
Strong points and limits
Strong points
- Free and MIT licensed
- HTML and JSON reports
- Merges results across test suites
- Optional mapping to RSpec and Minitest tests
- Changed-line coverage can enforce a threshold
Limits
- Must start before application code is required
- JRuby supports line coverage only
Who it suits
SimpleCov suits Ruby developers who want coverage reports, test mapping, or thresholds for changed lines. Teams using JRuby should note that only line coverage is supported there.
Verdict
SimpleCov provides configurable Ruby coverage reports, test mapping, and coverage gates at no cost. Its startup order matters for tracking application files, and JRuby users have line coverage only.
Where Specifiction places it
- Code Coverage Tools#6 of 107.4
- Test Coverage Tools#20 of 277.4
