diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..f28aaf9
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,53 @@
+# Contributing to MSDL
+
+Thanks for considering a contribution. This project is a small, community-run tool — bug reports, product additions, and fixes are all welcome.
+
+## Reporting bugs
+
+Open a [GitHub issue](https://github.com/starkSV/windows-iso-downloader/issues). Include:
+
+- Whether you hit it via the web app, the CLI, or both
+- CLI version (`msdl --help` prints it) or which page on msdl.tech-latest.com
+- The exact error message, if any
+- Product/language you were trying to fetch
+
+## Development setup
+
+See the [README's "Running Locally" section](./README.md#running-locally) for backend and frontend setup. For the CLI:
+
+```bash
+cd cli
+go run . --help
+go test ./...
+```
+
+## Adding a new consumer Windows release
+
+1. Find the product ID at `www.microsoft.com/software-download-connector/api/`
+2. Add it to `frontend/public/data/products.json` (name, archs, badge, related, active)
+3. Add it to `cli/catalog.go`'s `consumerProducts` slice
+4. Update the product table in `README.md`
+
+## Adding a new evaluation edition
+
+1. Find the fwlink URL at `microsoft.com/en-us/evalcenter/download-*`
+2. Add the slug and fwlink to the `evalProducts` map in `backend/main.go`
+3. Add the same slug to `cli/catalog.go`'s `evalProducts` slice
+4. Add the product config to `frontend/src/data/evalProducts.ts`
+5. Update the eval table in `README.md`
+
+## Making changes
+
+- Small, one-line config fixes can go straight to `main`.
+- Anything touching behavior (new feature, bug fix, refactor) should go through a feature branch and PR.
+- **Test locally before opening a PR** — build and run the affected component (`go build`, `go test ./...`, `npm run dev`) rather than relying on review to catch it.
+- Commit messages follow [Conventional Commits](https://www.conventionalcommits.org/): `feat:`, `fix:`, `docs:`, `chore:`.
+- Keep PRs focused — one fix or feature per PR, not a bundle of unrelated changes.
+
+## CLI releases
+
+CLI releases are cut by the maintainer via git tag (`cli/vX.Y.Z`), which triggers the GitHub Actions build for all platforms and the winget package update. Contributors don't need to worry about tagging, versioning, or winget — just get the fix or feature merged to `main`.
+
+## Code style
+
+No linter is enforced yet — match the surrounding code's style (Go: stdlib-first, minimal dependencies; frontend: existing Tailwind/component patterns). Don't add abstractions, comments, or error handling beyond what the change actually needs.
diff --git a/README.md b/README.md
index 1fc6d1a..43dc901 100644
--- a/README.md
+++ b/README.md
@@ -343,18 +343,7 @@ Recommended setup:
 
 ## Contributing
 
-Pull requests welcome. To add a new consumer Windows release:
-
-1. Find the product ID on `www.microsoft.com/software-download-connector/api/`
-2. Add it to `frontend/public/data/products.json` (name, archs, badge, related, active)
-3. Update the product table in this README
-
-To add a new evaluation edition:
-
-1. Find the fwlink URL on `microsoft.com/en-us/evalcenter/download-*`
-2. Add the slug and fwlink to the `evalProducts` map in `backend/main.go`
-3. Add the product config to `frontend/src/data/evalProducts.ts`
-4. Update the eval table in this README
+Pull requests welcome — see [CONTRIBUTING.md](./CONTRIBUTING.md) for dev setup, how to add products/eval editions, and PR conventions.
 
 ---