Generate a .gitignore template for your development stack

Choose the technologies and operating systems used by your repository, and this generator combines their standard ignore patterns into one deterministic file. Duplicate stack names and overlapping patterns are removed while the first useful ordering is preserved. Unknown names produce a clear input error instead of silently creating an incomplete template, making the result suitable for scripts, project scaffolding, and repeatable repository setup.

Choose every stack that creates local artifacts

Start with the languages, runtimes, editors, and operating systems that actually touch the repository. A Node project developed on macOS may need both the node and macos sets, while a mixed backend can combine node, python, and java. Including each relevant stack matters because generated artifacts come from more than the main programming language: package managers create caches, test tools create coverage reports, editors create project metadata, and desktop systems add filesystem records. The generator accepts stack names without regard to letter case and trims surrounding spaces, so values such as Node and node select the same catalog entry. Repeating a stack does not repeat its rules. An unfamiliar name is rejected explicitly, which prevents a misspelling from producing a file that appears complete but omits an entire toolchain. Keep the selection tied to tools contributors really use; adding unrelated ecosystems can hide files that a future contributor reasonably expects Git to track.

Understand how patterns are merged and deduplicated

The selected catalogs are processed in the order you provide them. Within each catalog, established ignore patterns retain their published grouping order. When the same exact pattern appears again, only its first occurrence remains. For example, build output or coverage directories are common to several ecosystems, but the generated file contains each matching rule once. This exact-line deduplication is intentionally conservative: two patterns that look similar can have different Git semantics, especially when one is anchored, uses a wildcard, or restores a file with an exclamation mark. The generator therefore does not rewrite, broaden, sort, or attempt to simplify rules. That choice keeps behavior predictable and avoids changing the meaning of a standard template merely to shorten it. The response includes the normalized stack list, the final number of unique patterns, and the complete gitignore text with a trailing newline, so it can be inspected, saved directly, or compared reliably in automated tests.

Review the result before adopting it

Treat a generated .gitignore as a strong baseline rather than a substitute for repository knowledge. Read the result before committing it, particularly rules for dependency locks, build directories, environment files, editor settings, and vendored code. Some teams intentionally commit files that another project excludes; Rust applications often track Cargo.lock, for example, while library policies can differ. Add project-specific rules after the generated block and remove any standard rule that conflicts with your release or reproducibility policy. If files are already tracked, adding them to .gitignore does not remove them from Git history or the index, so handle that migration separately and carefully. Because generation is deterministic and does not use a network, the same ordered stack list always returns the same text. That makes the tool useful in scaffolding scripts: store the chosen inputs alongside the project template, regenerate when the catalog changes, and review the resulting diff instead of copying an unknown template from a search result.