Why a SIP Softphone Should Be a Browser

LONDON - May 14, 2026 - PRLog -- By Justin Downes, Independent Technology Writer covering enterprise communications and AI

Justin Downes spoke with Conrad De Wet of Siperb this week about a position behind almost every decision his team makes: in 2026, a SIP client should be built on WebRTC, not the other way around.

For two decades, WebRTC has been treated as the thing you bolt onto a SIP estate when a browser needs to make a call. De Wet argues that framing is backwards.

"Our belief is that WebRTC is the right way for a SIP client to operate," De Wet told the OpenSIPS Summit in Bucharest. He pointed to two principles he described as super important in a SIP softphone: encrypted media by default, and transport handled over secure TLS-based communication.

The security argument is becoming the buying argument

A generation of SIP softphones still ships with UDP transport and unencrypted RTP. That was acceptable when interop was the priority. It is increasingly a procurement red flag in 2026. WebRTC enforces what older softphones treated as optional: encrypted media, secure signalling, and the browser security model on top.

The dual-registration architecture

There is a well-known objection to browser-based SIP: the browser sees the SIP credentials. Siperb designed around it.

The client registers to the Siperb platform over WebSocket. The platform then performs a second registration to the customer's SIP PBX — Asterisk, another OpenSIPS deployment, FreeSWITCH, or whichever stack sits on the other side. That upstream side, De Wet said, is what Siperb calls connections.

The customer's SIP credentials never reach the browser. The client's real IP is masked from the upstream infrastructure, because media is anchored on the platform's path rather than carried end-to-end. For organisations running PBXs they would rather not expose to the public internet, that matters.

Connections without registration

Siperb's upstream side does not require the customer PBX to register outward. The platform exposes static IPs on its SBCs; a customer PBX can send an INVITE to Siperb directly, and the platform locates the right device, handles push notification and provisioning, and brings the call down.

What to watch next

The industry has spent years asking whether WebRTC is ready to replace native SIP clients. In 2026, the more honest question is whether new native SIP clients should be built at all, when WebRTC delivers encryption, transport security, and cross-platform reach as defaults.

De Wet's answer is unambiguous: the softphone is a browser now, and the SIP stack belongs behind it.

Siperb's WebRTC-to-SIP architecture and technical documentation are at siperb.com