The first open source tool to make presentations interactive

Most presentation tools treat audiences as spectators. Claper was built to give them a voice. Live polls, Q&A, reactions all happening in real time, whether the room has 5 people or 500.

The problem

Presentations are one-directional by default. Speakers talk, audiences listen. Existing interaction tools were either clunky, proprietary, or couldn’t keep up at scale. We needed something fast, reliable, and open.

How we built it

We chose Elixir with the Phoenix framework a natural fit for low-latency, real-time features. Phoenix LiveView replaced the need for a separate frontend framework like React or Vue, keeping the stack lean and reducing round-trip complexity.

Under the hood, OTP supervision trees give Claper fault tolerance by design: a single failing connection never cascades to the rest. Every interaction flows through Phoenix Channels, delivering instant updates to all connected clients simultaneously.

I designed and built the entire product end to end: from the UI and brand identity to the Elixir backend. The result is a self-hostable platform (single Docker image) that gives teams full control over their data without sacrificing performance.

Results

Today Claper has 700+ stars on GitHub and 10,000+ users who have created thousands of events across industries: private companies to schools to healthcare organizations, with audiences ranging from 5 to 500+ attendees.

“I am currently utilizing Claper for my business and find it to be a fantastic tool for our needs.” ZhenHong L.

“I absolutely love Claper. I’m expanding my circle of folks utilizing the software.” Brandon P.