# Share a SimpleCov Coverage Report — coverage/index.html, With a URL

Canonical: https://commareports.com/share-simplecov-report
Published: 2026-08-30

> SimpleCov writes coverage/index.html plus assets, and it never leaves the machine that ran the specs. Publish the folder to Comma for a link the whole team can open and annotate.

# Share a SimpleCov coverage report

Every Ruby project has the same ritual. CI prints `Line Coverage: 78.4%`,
someone screenshots it, and the actual report — the one that shows _which_
lines are uncovered — never leaves the runner.

SimpleCov's default formatter writes a real, browsable artifact:

```
coverage/
  index.html
  assets/0.12.3/…      # css, js, DataTables, the sort widgets
  .last_run.json
```

Which is a folder, not a file. That is the whole reason it never gets shared.

## Publish the folder

Drag `coverage/` (or a zip of it) into [the app](https://commareports.com/):

- `index.html` becomes the report body.
- `assets/` uploads alongside it with the relative references rewritten to the
  uploaded copies.
- Scripts run inside a sandboxed iframe, so the group tabs, the sortable file
  table and the per-file source view all work.

## From CI

```ruby
# spec/spec_helper.rb
require "simplecov"
SimpleCov.start "rails"
```

```bash
bundle exec rspec

curl -fsS -X PATCH "https://commareports.com/api/v1/reports/$REPORT_ID" \
  -H "Authorization: Bearer $COMMA_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d "$(jq -n --rawfile html coverage/index.html \
        --arg title "Coverage — $GITHUB_SHA" '{title: $title, html: $html}')"
```

PATCHing one report id per repository keeps a single URL for "our coverage"
and appends a revision per run — so a drop is a diff between two revisions
instead of a number someone half-remembers from last sprint.

Wrap the publish step so it runs on failure too (`if: always()` on GitHub
Actions, `when: always` on GitLab and CircleCI, `post { always { … } }` on
Jenkins).

## What review adds

Coverage arguments are never about the percentage. They are about which
uncovered lines matter:

- **Anchored threads** on the file or the line range — see
  [commenting on HTML](/comment-on-html).
- **Revisions** so a coverage cliff has a visible before and after.
- **Access per report** — private, team, domain-gated, or named reviewers.
  See the [sharing model](/docs/sharing).

## Limits

- **Entry HTML: 5 MB.** A monolith's file index can get close; SimpleCov
  groups help. Assets: 25 MB per file, 250 MB and 500 files total.
- **60 requests/minute per token.**

## Try it

Comma is free — unlimited reports, unlimited commenters, unlimited revision
history.

**[Publish a coverage report →](https://commareports.com/)**

### Related

- [Share an RSpec report](/share-rspec-report) · [Share a coverage report](/share-coverage-report)
- [Share a RuboCop report](/share-rubocop-report) · [Share a Brakeman report](/share-brakeman-report)
- [Share an LCOV report](/share-lcov-report) · [Publish from CI](/docs/ci)