WhatsApp vs Signal: Which Is More Private?

WhatsApp and Signal both use end-to-end encryption. Both claim to protect your messages. But beneath the surface, the two apps have fundamentally different approaches to privacy — one is a product of a surveillance-advertising business; the other is a non-profit whose only product is private communication.

The encryption question

Both apps use the Signal Protocol for end-to-end encryption of messages and calls. This means neither WhatsApp nor Signal can read the content of your messages in transit. A government requesting your messages from WhatsApp would get ciphertext it cannot read.

On message content alone, both apps offer strong, genuine protection. This is not marketing language — it's a well-audited cryptographic implementation.

But encryption of content is only part of the privacy picture.

The metadata problem

WhatsApp collects extensive metadata about your communications — even though it can't read the messages themselves. This includes:

• Who you communicate with and how often
• When you sent messages and how long conversations lasted
• Whether you're online and when you last used the app
• Which groups you belong to
• Your device, IP address, and network information

Metadata can be as revealing as content. Intelligence agencies have noted for years that "metadata absolutely tells you everything about somebody's life." Knowing who you call, when, and how often maps your relationships, habits, and movements without ever reading a single message.

Signal collects almost none of this. The only data Signal retains is your phone number (required to create an account) and the date your account was created. In 2021, Signal was subpoenaed by a US grand jury. They had nothing to hand over except those two fields.

Who owns the data?

WhatsApp is owned by Meta Platforms — the company that also operates Facebook and Instagram. WhatsApp's privacy policy explicitly states that it shares your data with "Meta Companies" for advertising and product improvement. Your WhatsApp usage — who you contact, your device, your approximate location — feeds Meta's advertising machine across Facebook and Instagram, even if you don't actively use those platforms.

You cannot opt out of this data sharing and continue using WhatsApp. It is a condition of use.

Signal is operated by the Signal Foundation, a non-profit with no advertising business. Signal's revenue comes from donations. There is no advertising product to feed, and no parent company to share your data with.

Contact upload

When you use WhatsApp's contact sync feature, the phone numbers of everyone in your address book are uploaded to Meta's servers — including people who have never agreed to WhatsApp's privacy policy. Your contacts have no say in this.

Signal offers optional contact discovery, implemented using a privacy-preserving cryptographic technique (sealed sender, private contact discovery) that verifies which of your contacts use Signal without the Signal servers learning who they are.

Business messages

When you message a business on WhatsApp, the end-to-end encryption only applies to the delivery channel. The business receives your message in plaintext, and may grant Meta and third-party service providers access to read, store, and process those messages on their behalf. You have no visibility into which businesses share your conversations this way.

Signal does not offer a business messaging tier with these characteristics.

Side-by-side summary

Feature	WhatsApp	Signal
Message content encryption	✓ End-to-end	✓ End-to-end
Metadata collected	Extensive	Minimal (phone number, join date)
Data shared with advertiser	Yes (Meta)	No
Non-profit / no ads	No	Yes
Contact upload privacy	Contacts uploaded to Meta	Private contact discovery
Subpoena data available	Metadata	Phone number, join date only

The verdict

For private communication, Signal is significantly more private than WhatsApp. The encryption is comparable, but everything around the encryption — metadata, ownership, data sharing, and business model — points in the same direction: Signal is built for privacy; WhatsApp is built for scale inside an advertising business.

WhatsApp is more convenient for many people — most of the people you know are already on it, and that's a genuine advantage. But if privacy is the priority, Signal is the clearer choice.

See our full WhatsApp privacy analysis (grade: D, score: 35/100) for the complete breakdown. For comparison, you can also compare WhatsApp against Apple's iMessage using our comparison tool.