Home / Team Communication / Signal

Signal — open source alternative

Encrypted messaging for individuals and small groups.

Strengths

  • Gold-standard end-to-end encryption.
  • Non-profit governance.
  • Clean, minimal UX.

Weaknesses

  • Requires phone number for registration.
  • Self-hosting the server is effectively impossible in practice.
  • Not designed for large teams or admin controls.
License: AGPL-3.0 / GPL-3.0 Self-host difficulty: 5/5 Hosted cloud optionDesktop: Windows, macOS, LinuxMobile: iOS, Android

Official site · Source on GitHub

Ad slot — OSS middle

Signal is used as an alternative to

WhatsApp

Global mobile messaging.

See all alternatives →

More open source in this category

Discover other projects tagged Team Communication on the category page.

Other open source projects in Team Communication

Mattermost

Slack-style open source team messaging.

License: AGPL-3.0 / Apache-2.0 (modules)

Rocket.Chat

Open source team and community chat with video and voice.

License: MIT (community); proprietary modules available

Zulip

Threaded team chat with topics.

License: Apache-2.0

Recommended reading

Why your team probably can't ditch Slack yet (and what needs to change)

Mattermost and Rocket.Chat are excellent. So why do most teams who try to migrate away from Slack end up back on Slack? An honest look at the real blockers.

When self-hosting goes wrong: seven failure modes and how to avoid them

An honest retrospective on the ways self-hosted setups break — not in theory, but in practice — and the small habits that prevent most of them.

Will the open source project you depend on still exist in three years?

Bus factor, maintainer burnout, funding models, and the signals that separate OSS projects that survive from those that quietly decay.