Open Source Alternatives
  • Alternatives
  • Categories
    Categories by size905 projects
    • Developer Tools471
    • AI & Machine Learning408
    • Web Development198
    • Business & Productivity196
    • Security & Monitoring131
    • Communication & Collaboration128
    • IT Management126
    • Cloud & Hosting109
    • Product & Project Management106
    • Data & Analytics105
    Browse all 21 categoriesDesign & Creative, LLMOps & AI Tooling and 9 more
  • Blog
  • Advertise
SearchNotion, Slack, password manager.../
Submit
Open Source Alternatives
  • Alternatives
    • Developer Tools471
    • AI & Machine Learning408
    • Web Development198
    • Business & Productivity196
    • Security & Monitoring131
    • Communication & Collaboration128
    • Browse all 21 categories
  • Blog
  • Advertise
Submit your project

New open source projects by email

The projects we add and every new guide. Free, unsubscribe any time.

Open Source Alternatives LogoOpen Source Alternatives

Handpicked Open Source Alternatives to Paid Softwares

Product

  • Categories
  • Tag
  • Advertise

Resources

  • Blog
  • Collection
  • Submit

Company

  • Privacy Policy
  • Terms of Service
  • Refund Policy
  • Sitemap

Alternatives

  • Claude Code
  • Jira
  • Notion
  • Slack
  • Linear
  • Wispr Flow
  • All alternatives
© 2026 Open Source Alternatives. All rights reserved.
Open SourceAlternatives
Home/Categories/Communication & Collaboration/Signal
icon of Signal

Signal

Open source alternative to WhatsApp and Telegram

  • 10.7K stars
  • AGPL-3.0
  • Active this week
  • Last commit 3 days ago

Last verified Oct 20, 2026

Secure private messaging with end-to-end encrypted chats, calls, groups, and public Signal client and server code.

Visit websiteGitHub10.7K stars
image of Signal
TL;DR

Signal is a private messaging service built around end-to-end encrypted communication and public client and server code. It replaces consumer messengers such as WhatsApp for privacy-focused users, but it is not a standard self-hosted team workspace and should not be sold as a deployment-control play.

Read the full breakdownHide the full breakdownWho it is for, how it works, trade-offs and the FAQ
who it's for

Who Signal is for#

Privacy-focused personal communication

Signal fits users and small groups that prioritize end-to-end encrypted messaging with a mainstream mobile experience.

Skip if:

Skip it if you need corporate workspace administration and compliance controls.

Organizations recommending private chat

Teams can recommend Signal for sensitive external conversations where a full workspace is unnecessary.

Skip if:

Do not choose it as the primary internal collaboration system if self-hosting and admin policy are required.

the problem

The problem it solves#

Consumer messaging apps often ask users to trust a provider with metadata, contact discovery, backups, or product incentives they cannot inspect. For sensitive personal or organizational conversations, that trust model is uncomfortable.

The main need is a widely usable private messenger with strong encryption defaults, not a configurable corporate collaboration suite.

how Signal solves it

How it solves it#

Signal Protocol encryption

Signal is built around end-to-end encrypted messaging using the Signal Protocol, which is widely studied and adopted beyond Signal itself.

Public client and server code

Signal publishes code for major clients and server components, giving security researchers and developers more visibility than closed messengers.

Private messaging features

Signal supports practical messaging needs such as one-to-one chats, groups, voice, media, and privacy-oriented defaults for everyday communication.

strengths · trade-offs

Strengths and trade-offs#

Strengths

  • Strong privacy positioningSignal's value is private communication for ordinary users, not enterprise workspace sprawl. That clarity makes it a strong WhatsApp alternative for privacy-first messaging.
  • Public implementation visibilityOpen repositories let researchers inspect parts of the implementation and track changes in a way closed consumer messengers do not allow.

Trade-offs

  • -Not a self-hosted workspaceSignal is a service and app ecosystem, not a standard self-hosted Slack or Teams replacement. Running an independent compatible service is not the normal usage path.
  • -Limited admin controlsOrganizations that need retention policies, legal hold, SSO, channel administration, and workspace analytics should choose a business collaboration platform.
tech stack · detected from GitHub

What it's built on#

Languages
Java
frequently asked

FAQ#

Is Signal open source?

Signal publishes client and server code in public repositories, including AGPL-3.0 licensed server code.

Can I self-host Signal for my company?

Signal is not designed as a standard self-hosted team workspace. Most users use the official Signal service.

Is Signal a WhatsApp alternative?

Yes, for privacy-focused consumer messaging. It is not a replacement for enterprise collaboration suites.

also worth a look

Similar open-source tools#

simplex-chat

Alternative toWWhatsApp

Private messaging without user IDs or servers.

  • 19,580 GitHub stars
  • AGPL-3.0Licence AGPL-3.0

Jami

Alternative toWWhatsApp

Free P2P encrypted messaging, calls, and file sharing

  • 168 GitHub stars
  • GPL-3.0Licence GPL-3.0

Inbox Zero

Featured

Alternative toSuperhuman

AI email assistant that drafts replies and clears your inbox

  • 12,712 GitHub stars
  • AGPL-3.0Licence AGPL-3.0

MediaWiki

Alternative toConfluence

Wiki software powering Wikipedia, self-hosted and GPL-2.0 licensed.

  • 5,210 GitHub stars
  • GPL-2.0-or-laterLicence GPL-2.0-or-later

BookStack

Alternative toConfluence

Self-hosted team wiki with WYSIWYG editing and built-in diagrams

  • 299 GitHub stars
  • MITLicence MIT

Oxynote

Alternative toNotion

Technical wiki with live metrics, draft reviews, and real-time editing

  • 244 GitHub stars
  • Apache-2.0Licence Apache-2.0
by category

Open source tools in these categories#

128

Communication & Collaboration

freeCodeCamp, iptv, Excalidraw
195

Business & Productivity

OpenClaw, Excalidraw, RustDesk

Featured

Omnara

Alternative toCClaude Managed Agents

Open-source agent deployment API. Self-host or use Omnara Cloud.

  • 2,957 GitHub stars
  • Apache-2.0Licence Apache-2.0
  • #AI Agents

Inbox Zero

Alternative toSuperhuman

AI email assistant that drafts replies and clears your inbox

  • 12,712 GitHub stars
  • AGPL-3.0Licence AGPL-3.0
  • #Email

rakazo

Alternative toGrok Bot

AI teammates you own: your keys, your model, your machine.

  • 4,904 GitHub stars
  • Apache-2.0Licence Apache-2.0
  • #AI Agents
Feature your project

New open source projects by email

The projects we add and every new guide. Free, unsubscribe any time.

Find open source alternatives to paid software

/
  • Claude Code to OpenCode
  • Jira to Windshift
  • Notion to AppFlowy
  • Slack to Mattermost
  • Linear to GitLab
  • Wispr Flow to Handy
  • CapCut to Concat
  • Grok Bot to rakazo
  • Superhuman to Inbox Zero
  • Airtable to AITable
  • Muse to OpenClaw
  • GitHub Copilot to Cline
  • Datadog to Netdata
  • Microsoft Teams to Rocket.Chat
  • Confluence to Docmost
  • Pinecone to Qdrant
  • Zapier to n8n
  • Devin AI to OpenHands
  • Firebase to Supabase
  • 1Password to KeePassXC
  • Contentful to Strapi
  • Adobe Premiere Pro to Shotcut
  • ChatGPT to AnythingLLM
  • LangSmith to Langfuse
  • Claude Code to OpenCode
  • Jira to Windshift
  • Notion to AppFlowy
  • Slack to Mattermost
  • Linear to GitLab
  • Wispr Flow to Handy
  • CapCut to Concat
  • Grok Bot to rakazo
  • Superhuman to Inbox Zero
  • Airtable to AITable
  • Muse to OpenClaw
  • GitHub Copilot to Cline
  • Datadog to Netdata
  • Microsoft Teams to Rocket.Chat
  • Confluence to Docmost
  • Pinecone to Qdrant
  • Zapier to n8n
  • Devin AI to OpenHands
  • Firebase to Supabase
  • 1Password to KeePassXC
  • Contentful to Strapi
  • Adobe Premiere Pro to Shotcut
  • ChatGPT to AnythingLLM
  • LangSmith to Langfuse