Signal Now Supports 40 Person Group Calls

New Delhi: Signal, an encrypted messaging app, has announced that group calls may now accommodate up to 40 people.

The business claimed it first introduced end-to-end encrypted group calls a year ago and has since expanded its support from five to 40 members.

"There is no off the shelf software that would allow us to support calls of that size while ensuring that all communication is end-to-end encrypted, so we built our own open-source signal calling service to do the job," the company said in a blog post.

When Signal was developing support for group calls, it tested several open-source selective forwarding units (SFUs), but only two of them provided appropriate congestion control.

"We launched group calls using a modified version of one of them, but shortly found that even with heavy modifications, we couldn’t reliably scale past eight participants due to high server CPU usage," the company said.

To accommodate additional users, the business created a new SFU in Rust from the ground up.

It has been supporting all Signal group conversations for nine months, can easily expand to 40 people, and is readable enough to serve as a reference implementation for an SFU built on WebRTC protocols, according to the business.