Codecov is a hosted coverage service. A GitHub Action (or
another CI integration) uploads your coverage report to Codecov's servers
on every build. Public repositories on GitHub Actions can upload without a
token; private repositories need one, or the newer OIDC-based
authentication. Once connected, Codecov keeps a historical dashboard
across every branch and contributor, posts a PR comment, and can fail a
check on two different signals — codecov/patch
(coverage of the lines this PR touched) and codecov/project
(overall coverage) — configured through an optional
codecov.yml file.
That is a genuinely useful job for a team that wants it running on every build without thinking about it, and it is not this tool's job. This page parses the two coverage XML reports you paste — nothing is uploaded, there is no account, and nothing is remembered once you close the tab.
| Question | Where to answer it |
|---|---|
| I have a baseline report and this PR's report right now — did line coverage drop? | Coverage Drop Check — paste both, get the percentage-point delta and which files moved, no signup, nothing leaves your device. |
| I want a coverage status check and PR comment on every build, automatically, for the whole team. | Codecov — that needs an ongoing CI integration and an uploaded report on every run, which a stateless browser page never does. |
| I want historical coverage trends across branches and contributors, or a badge for my README. | Codecov's dashboard — this tool has no memory between visits and nowhere to keep history. |
| My CI already writes coverage.xml or jacoco.xml and I don't want to connect an account or upload it just to check one PR. | Coverage Drop Check — the browser page never makes a network request, and the CLI never phones home either. |
The two are not substitutes. A team that wants an always-on, connected, historical coverage dashboard with PR comments across every repository needs a hosted tool like Codecov — a page that only looks at whatever you paste into it, once, cannot do that job. A person who already has a baseline report and a PR report and wants the delta before signing up for anything, or without sending code-coverage data to a third party at all, does not need an account or a CI integration to get it.
They answer a similar question — did coverage get worse — for different situations. Codecov is a hosted service: a GitHub Action (or other CI integration) uploads your coverage report to Codecov's servers on every build, where it is stored, shown on a historical dashboard, and used to post codecov/patch and codecov/project status checks plus a PR comment, across every branch and contributor, continuously, once it is connected. Coverage Drop Check is a free tool with no account and no connection: you paste the baseline report and the current report you already have and get a deterministic percentage-point delta and a per-file breakdown in your browser, right now, with nothing sent anywhere. It answers "did this specific PR drop coverage compared to this specific baseline", once, for whoever is looking at two XML files this minute. If you want an always-on team dashboard with history and PR comments wired into every build, Codecov's job is not one this page tries to do. If you have two reports in hand and want the delta before signing up for anything, that is what this tool is for.
No. There is nothing to connect and nothing to sign up for. The browser page parses the XML you paste entirely on your own device and never sends it anywhere; the CLI reads local files and makes no network call at all. Codecov's own public documentation describes the opposite model: its GitHub Action uploads your coverage report to Codecov's servers on every run so the dashboard and status checks can work, and while public repositories on GitHub Actions can upload without a token, using it at all still means creating a Codecov account, installing its GitHub App or Action, and sending your coverage report to Codecov's infrastructure on every build.
Yes — a persistent historical dashboard across every build and contributor, native PR comments and commit statuses wired directly into GitHub without pasting anything by hand, coverage badges, support for many more report formats through its universal uploader (LCOV and Clover included, where this tool reads only Cobertura and JaCoCo), and team-wide visibility across many repositories at once. None of that is possible from a page with no server, no account and no memory between visits. This tool only ever computes the delta between the two specific reports you paste into it in that session.
No. This site is not affiliated with, endorsed by, or sponsored by Codecov, Inc. Codecov is named here only to describe what this tool is and is not, based on Codecov's own public documentation.