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+<!--
+This file is part of Share₂Fedi
+https://github.com/kytta/share2fedi
+
+SPDX-FileCopyrightText: © 2023 Nikita Karamov <me@kytta.dev>
+SPDX-License-Identifier: CC0-1.0
+-->
+
+# Contributing guide
+
+First off, thank you for considering contributing to Share₂Fedi! There are many
+ways you can improve on the project:
+
+- [write new and improve on the old code](#improving-code)
+- [write documentation](#writing-documentation)
+- [translate UI strings](#translating)
+- [report bugs](#reporting-bugs)
+
+Please, follow this guide if you want to contribute. We promise, it's not too
+many rules! Following this helps us merge changes quicker!
+
+Unsure where to begin contributing? You can start by looking through
+[the help-wanted issues](https://github.com/kytta/share2fedi/labels/help%20wanted)!
+
+## Improving code
+
+Before you start, make sure you've got a fresh Node.js version (v18 should work)
+installed. You'll also need to [install pnpm](https://pnpm.io/installation), as
+this is our package manager of choice.
+
+1. Fork the repository and clone it
+2. Install dependencies:
+
+   ```sh
+   pnpm install
+   ```
+
+3. To start a dev server, run:
+
+   ```sh
+   pnpm dev
+   ```
+
+   This server will auto-update on changes to the file
+
+4. After implementing a feature, create a new Git branch and commit your changes
+   on it
+5. Push the branch and open a PR.
+
+### Adding support for other Fediverse projects
+
+In order for a Fediverse project to be supported, it has to have a "Share" page
+located at a fixed address. That means, that the address is the same for all
+users and all frontends. For example, Mastodon's "Share" page is always at
+`/share`. The share page should also accept the text of the post via URL
+parameters. For example, Mastodon allows pre-filling the text of a post using
+`?text=`. Lastly, it should be listed on
+[fediverse.observer](https://fediverse.observer/).
+
+If the Fediverse project satisfies these requirements, you can add it to
+Share2Fedi. For this:
+
+1. Add an entry to `supportedProjects` inside `src/lib/project.ts`.
+   - keep the list in alphabetical order
+   - the key should match the software name from NodeInfo/fediverse.observer
+   - the value should be an object of type `ProjectPublishConfig`. The endpoint
+     is the path to the "Share" page (leading slash optional).
+   - if the service you're adding is a flavour of an already supported service,
+     use the variable to reduce code duplication. See `mastodonConfig` for an
+     example
+2. Pick an instance of the project you've added and visit
+   `/api/detect/<INSTANCE-DOMAIN>`. Make sure the detection is correct
+3. Go to the `/` and try to share something to the instance. Make sure the
+   "Share" page opens with correct parameters.
+
+## Writing documentation
+
+Share₂Fedi's documentation is pretty complete at the moment, but you are free to
+fix errors and to add clarifications. The only documentation we have is the
+`README.md` and `CONTRIBUTING.md` that you're reading right now.
+
+## Translating
+
+Starting with v3, Share₂Fedi has a very primitive translation framework built
+in. Despite it being simple, you can edit translations and add new languages in
+form of JSON-based dictionaries.
+
+There are two ways you can add/edit translations:
+
+1. The JSON files under `src/i18n/translations` represent dictionaried for
+   different languages. The two-letter codes correspond to the ISO 639-1
+   language codes.
+   - to edit translations, just edit the files. Refer to
+     [the coding guide](#improving-code) for more information on how to do this.
+2. [Weblate](https://translate.codeberg.org/engage/share2fedi/), a web-based
+   tool that simplifies this process.
+   - we use Codeberg's Weblate instance, which requires a Codeberg account. If
+     you have one, this is the easiest way to edit translations.
+
+## Reporting bugs
+
+> [!IMPORTANT]  
+> If you find a security vulnerability, do NOT open an issue. Email
+> [Nikita Karamov](mailto:me@kytta.dev) instead.
+
+If you find a bug you can't (or don't want to) fix yourself, don't hesitate
+filing an issue. We do not have a preset issue template, but try to answer these
+questions in the issue body:
+
+1. What version of Share₂Fedi are you using?
+2. How do you deploy it (Node/Vercel/Netlify/Cloudflare/Deno)?
+3. What did you do?
+4. What did you expect to see?
+5. What did you see instead?
+
+---
+
+We are looking forward to your contributions!