Why Some Businesses Will Never Move Their PBX to the Cloud — And How Siperb Built Around It

LONDON - Aug. 10, 2026 - PRLog -- Justin Downes spoke with Conrad De Wet of Siperb about a problem almost every cloud-based communications vendor eventually hits: the customer whose PBX sits in a server room on the LAN, with no intention of putting it on the internet.

The usual answer is to tell that customer to migrate. De Wet's answer was different — build a media bridge that lives inside the desktop client, and at the OpenSIPS Summit in Bucharest, he explained how.

"Our Asterisk box is locally in the LAN," De Wet recalled a customer telling him, "and we're not putting it on the internet." That conversation forced a rebuild: WebRTC to SIP, with the media proxy running locally, inside the desktop application.

What the bridge does

Written in Go, the component runs inside the Siperb desktop client and terminates the WebRTC connection locally on the user's machine. To the browser, it looks like a normal WebRTC endpoint. To the customer's PBX, it looks like a normal SIP endpoint carrying plain media.

In between, it does the work that would normally sit on cloud infrastructure: terminating the WebSocket connection, proxying signalling to the upstream SIP server, and — for media — altering the SDP, inserting itself as the media server, stripping DTLS encryption from the RTP stream, and forwarding plain media in whatever codec the upstream server expects.

Why it matters

The conventional fix for this problem is a small on-premises appliance — a session border controller or RTP relay with its own chassis and maintenance contract. That works, but it adds hardware to a deployment that was meant to be software-only.

By handling termination inside the client instead, Siperb keeps the deployment model intact: the customer downloads a softphone, and the softphone knows how to behave like a media-aware SBC when it needs to. No extra box.

Built with an AI-assisted feedback loop

De Wet was candid about how it was built: roughly two days of work with an AI assistant, from a detailed instructions document to a working Go version, with a tight log-analysis feedback loop keeping errors low.

What to watch next

De Wet's view is that the industry's assumption — that anything not in the cloud is a problem to be migrated — will age badly. Customers whose PBX stays in the building aren't going away, and vendors who build for that reality, rather than against it, are the ones who will win those accounts.

Siperb's local media bridge and on-premises SIP integration documentation is available at siperb.com (https://www.siperb.com).