Compare messengers¶

Choose two to four messengers. Every property comes from the same traceable catalogue; unknowns remain explicit.

Property	Signal	SimpleX
Account identifier	Registration phone number; optional username. [1] [2]	Local profile; relationship-specific invitations. [1] [2]
Phone required by service	Yes, even when hidden from the contact. [1] [2]	Not required. [1] [2]
E2EE	Mature E2EE for messages and calls; endpoint security remains crucial. [1] [2]	Double Ratchet E2EE; message padding is declared. [1] [2]
Metadata exposure	Service knows the number; some account dates were publicly disclosed. [1] [2]	No global account; relays, queues, timing and iOS push remain exposure surfaces. [1] [2]
IP exposure to peer	Calls can be relayed; check the setting and actual network path. [1] [2]	Default TURN hides IP from the peer; P2P can reveal it. [1] [2]
Multi-device	Primary iPhone; official desktops linked through the phone. [1] [2]	Documented mobile–desktop pairing on the same local network; desktop beta. [1] [2]
Main strength	Mature content security, adoption and iPhone + PC usability. [1] [2]	Relationship separation without a mandatory global identifier. [1] [2]
Main weakness	Mandatory number known to the provider and telecom layer. [1] [2]	More multi-device friction; relays and notifications require care. [1] [2]
Best suited for	Everyday security; peer-facing pseudonymity with hardened settings. [1] [2] [3] [4]	Pseudonymous online contacts; minimising account identifiers. [1] [2] [3] [4]
Confidence and scope	Scope-limited documentary evidence; production metadata and distributed binaries not experimentally verified. [1]	Scope-limited documentary evidence; production metadata and distributed binaries not experimentally verified. [1]

Technical details: identity, keys, push, devices, audits and evidence

Property	Signal	SimpleX
Email requirement	Unknown: not established for the version and configuration in question.	Not required. [1] [2]
Username / discovery	Optional; no public username directory. [1] [2]	No mandatory global username; optional public address should be avoided for compartmentalisation. [1] [2]
Number visible to contact	Can be hidden: number visibility AND discovery set to Nobody; a number already known to the contact is not forgotten. [1] [2]	No required number to disclose. [1] [2]
Global user ID	Service account remains linked to the phone number. [1] [2]	No global user ID required. [1] [2]
Forward secrecy	Documented protocol property; depends on clients and linked devices. [1] [2]	Documented Double Ratchet; versions and implementations still need verification. [1] [2]
Post-compromise security	Cryptographic recovery after temporary compromise; not while spyware remains in control. [1] [2]	Post-compromise recovery described by the protocol; requires an uncompromised endpoint. [1] [2]
Key verification	Out-of-band Safety Number; AKV does not certify identity and requires the other account’s number. [1] [2]	Unknown: not established for the version and configuration in question.
Relay / TURN	Enable Always Relay Calls when peer IP exposure matters; the relay sees the IP. [1] [2]	Always use relay; TURN sees IP and duration. [1] [2]
What the provider learns	Registration number and limited account data; not normal E2EE content by design. [1] [2]	Relays see their transport data; message bodies are E2EE. Declared non-logging was not measured here. [1] [2]
What the contact learns	The contact receives messages and the profile you share, and can keep a copy. [1] [2]	The contact receives messages and the profile you share, and can keep a copy. [1] [2]
What the network / ISP learns	The network sees destinations, timing and volume; Tor or a relay changes the observer. [1] [2]	The network sees destinations, timing and volume; Tor or a relay changes the observer. [1] [2]
Push notifications	Exact APNs payload not captured; manage local notification previews. [1] [2]	iOS push: queue and frequency data partly visible to the service; exact payload not captured. [1] [2]
Apple / Google exposure	Store, installation and push can create metadata; exact profile linkage depends on the OS and was not tested here. [1] [2]	Store, installation and push can create metadata; exact profile linkage depends on the OS and was not tested here. [1] [2]
Groups	Unknown: not established for the version and configuration in question.	Unknown: not established for the version and configuration in question.
Calls	Documented calls; their network path must be distinguished from messaging. [1] [2]	Documented calls; their network path must be distinguished from messaging. [1] [2]
Backups	Unknown: not established for the version and configuration in question.	Local profiles and history; complete version-specific backup guarantees not established here. [1] [2]
Source code and binaries	Repositories and component-specific scopes recorded in Phase 2; no current binary rebuilt bit-for-bit here. [1] [2]	Repositories and component-specific scopes recorded in Phase 2; no current binary rebuilt bit-for-bit here. [1] [2]
Audits	Protocols and AKV examined under distinct scopes; not the whole infrastructure or every binary. [1] [2] [3]	Trail of Bits 2022 and 2024 protocol review; announced 2026 review had no usable public report at the research cutoff. [1] [2] [3]
Public law-enforcement evidence	Published 2026 provider response: creation and last-connection dates for six accounts; not messages. [1] [2] [3]	2025 provider claim: 12 requests with no responsive information; no independent court dossiers. [1] [2] [3]
iOS	Yes, client listed in the study. [1] [2]	Yes, client listed in the study. [1] [2]
Android	Yes, client listed in the study. [1]	Yes, client listed in the study. [1]
Windows	Yes, client listed in the study. [1] [2]	Beta; desktop-specific limits. [1] [2]
macOS	Yes, client listed in the study. [1] [2]	Beta; desktop-specific limits. [1] [2]
Linux	Yes, client listed in the study. [1] [2]	Beta; desktop-specific limits. [1] [2]
Avoid if…	You refuse to give a number to the service. [1] [2] [3] [4]	You cannot accommodate profile, relay and local-pairing constraints. [1] [2] [3] [4]
Recommended configuration	Visibility and discovery: Nobody; fresh username, neutral profile, verified Safety Number, relayed calls when needed. [1] [2] [3] [4]	Fresh profile, single-use invitation, no reused identity; TURN; deliberate iOS notification choice. [1] [2] [3] [4]
Remaining unknowns	Current network behaviour, distributed binaries and forensic evidence remain incomplete; check version, OS and configuration. [1] [2]	Current network behaviour, distributed binaries and forensic evidence remain incomplete; check version, OS and configuration. [1] [2]
Ease of use	Very practical for iPhone + PC; the primary phone remains necessary. [1] [2] [3] [4]	More setup and friction than Signal; local pairing. [1] [2] [3] [4]
Network anonymity	No general resistance to a global passive observer is demonstrated. [1] [2]	No general resistance to a global passive observer is demonstrated. [1] [2]

Quick comparisons¶

End-to-end encryption — E2EE

Participants’ devices control content keys. The transport server should not read ordinary messages. Learn more

Pseudonymity

Use an identity different from your civil identity. It can still be linked to you. Learn more

Metadata

Data around the exchange: accounts, IP, timing, volume, devices or groups. Learn more

Network anonymity

Reduce the ability to link traffic to your network address or its destination. Learn more

Report 1.0 · 14 October 2026. No network lab, controlled forensic testing or bit-for-bit reproduction of binaries. Unknown remains Unknown.