Open-source Threads alternatives

Mastodon is a social network server, free and open source, that runs on the ActivityPub standard so users can follow friends and find new accounts. People can publish links, pictures, text and video. Every Mastodon server is interoperable with the others as a federated network, and it can also communicate with other software that implements ActivityPub. It is written in Ruby and released under the AGPL-3.0 license.

Features include real-time, chronological timeline updates, media attachments for images and videos, and safety and moderation tools such as private posts, locked accounts, filters for phrases, muting and blocking, plus reporting and moderation. Mastodon acts as an OAuth2 provider with a REST API and a Streaming API, which has produced a rich ecosystem of third-party apps.

The software belongs to the Fediverse, which is built on open standards and avoids vendor lock-in. The backend uses Ruby on Rails with PostgreSQL, and an official container image is available. You can run your own server or join an existing one, so it suits communities, organizations and individuals who want control over their social platform.

The Bluesky Social app is the official client for the Bluesky network on the web, iOS and Android. This repository holds its codebase, which is a React Native application written in TypeScript. It builds on the open-source atproto TypeScript packages, which live in a separate repository.

Bluesky is built on the Authenticated Transfer Protocol, known as AT Protocol or atproto, a decentralized social media protocol. The application includes a set of schemas and APIs in the app.bsky namespace. A small amount of Go code in the bskyweb directory implements a web service that serves the React Native Web version of the app.

The code is released under the MIT license. The maintainers accept contributions but prioritize high-quality issues and pull requests, say they may not respond to every issue, and do not provide support for build problems. Build instructions are in the repository, and the apps themselves are available from bsky.app and the mobile app stores.

Misskey is an open-source, federated social media platform. People post short updates to a timeline, and because it speaks ActivityPub it can exchange content with other servers across the fediverse. Anyone can run their own instance, so communities are not tied to a single company's service.

The project is developed in TypeScript and is released under the AGPL-3.0 license. Its website, misskey-hub.net, collects documentation and information on the wider project. Production deployments commonly use Docker, and the maintainers credit services for error tracking, visual testing, code coverage and localization that help the interface reach many languages.

Misskey describes itself as free forever and welcomes support in the form of GitHub stars. Releases follow a year and month numbering scheme. It suits communities and individuals who want a federated alternative to centralized social networks and are comfortable operating a server or joining an existing instance.

Elk is an open-source web client for Mastodon, described by its authors as nimble. Instead of using the web interface that comes with a Mastodon server, users can sign in to their account through Elk, which is built with Vue and Nuxt. The code is released under the MIT license.

The Elk team maintains an official deployment at elk.zone, plus a canary build that deploys on every commit to the main branch so testers can try the newest changes. The project invites feedback and contributions through open issues and a Discord server, and it publishes a list of known community deployments that use Elk as an alternative client for particular Mastodon servers.

Hosting your own copy is possible with the provided Dockerfile. Elk only loads properly over SSL or TLS, and the container does not handle that itself, so it should be placed behind a reverse proxy such as Traefik or NGINX. The container runs as a non-root user, and the settings directory needs permissions for the container user so account configuration can be saved.

Operately is an open source company operating system that helps coordinate goals, projects and teams without needing a COO. Unlike flexible tools such as Notion or ClickUp, it is opinionated: it provides the structure and proven workflows a growing company needs, from goal reviews and project check-ins to accountability routines.

Features include goals and OKRs linked to daily work, project management with task boards, milestones and consistent check-ins, team spaces for departments, message boards to replace scattered email threads, documents and files, team management with permissions, and an execution cadence of built-in check-ins and automated progress updates. A CLI and API give full programmatic access so AI agents can create goals, update projects and post check-ins, and published agent skills exist for Codex, Claude Code and other tools.

Operately is written in Elixir with a React and TypeScript front end, with a community on Discord. Its license is listed as Other, so review the repository terms before use.