Signal Foundation
end-to-end encrypted messaging from a nonprofit
| Overview | |
|---|---|
| Company | Signal Foundation |
| URL | signal.org |
| Pricing | free— Free, no ads, no paid tiers. Run by the Signal Foundation, a US 501(c)(3) nonprofit
funded by grants and donations; by charter it cannot be acquired. |
| License | open |
| Hosting | cloud |
End-to-end encrypted 1:1 and group messaging, plus voice/video calls, built on the audited Signal Protocol (Double Ratchet + X3DH). ~40M monthly users. Registration requires a phone number; usernames (added 2024) let you start chats without sharing it.
Usage Notes
Why it's strong for us: the most-scrutinized E2E encryption in production, from a mission-aligned privacy nonprofit that collects minimal metadata (sealed sender). Its published responses to legal demands show it can only produce registration and last-connection dates -- not messages, contacts, groups, or call logs. Free.
Deplatform caveat: Signal is deliberately centralized and does NOT federate or support self-hosting -- the Foundation runs every server, so an outage, protocol change, or government compulsion hits all users at once and you have no fallback infrastructure. Practical risk is low (privacy nonprofit, strong track record), but it does not clear our self-host bar. The self-hostable counterpart is Element.
Phone number: registration still needs one; usernames hide it from other users, but a subpoena can still map a username to the number. For high-anonymity threat models see SimpleX Chat (no identifier) or Briar (offline/mesh, censorship-resistant).
Rejected Alternatives
WhatsApp (uses the Signal protocol but is Meta-owned and harvests metadata) and Telegram (chats are not end-to-end encrypted by default, weaker crypto).