> Markdown version of [/events/world-congress-2026-europe-virtual-stage/sessions/1603-speeding-up-web-apps](https://www.wearedevelopers.com/events/world-congress-2026-europe-virtual-stage/sessions/1603-speeding-up-web-apps). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md).

---

# Speeding up Web Apps performance with WebAssembly and Emscripten


- **Event:** World Congress 2026 Europe - Virtual Stage

## Recording

[Watch recording](https://www.wearedevelopers.com/videos/1985-speeding-up-web-apps-performance-with-webassembly-and-emscripten)

## Description

WebAssembly enables running native C/C++ code in the browser at near-native performance. It allows us to bring the raw speed of native C/C++ libraries into the browser, making advanced software accessible without the need for rewriting everything from scratch or dealing with complex local installations. At the heart of this is Emscripten, a complete SDK that bridges the gap between native code and JavaScript, enabling near-native execution speeds in a web environment.

In this session, I will demonstrate the significant difference Wasm makes by comparing popular JavaScript crypto libraries with the battle-tested secp256k1 implementation from bitcoin-core. We’ll dive into the real-world engineering behind the PrivMX integration – a privacy-focused toolkit for simple implementation of end-to-end encryption in communication channels – showing how we use Emscripten to port a complex library and handle high-performance operations.

You'll learn where JavaScript hits a performance wall and how WebAssembly fills the gap, how to navigate the Emscripten SDK to compile, and bridge C++ libraries into a JavaScript environment. You will also see the tangible performance gains of using compiled C++ over native JS for elliptic curve operations (Secp256k1). Having implemented WebAssembly in the PrivMX stack, we have learned some practical lessons that I would like to share with you.

## Speaker

### [Paweł Aniszewski](https://www.wearedevelopers.com/@pawel-aniszewski)

Software Engineer at Simplito


## Related talks at this congress

- [De-bloating the Web: The "Ecosystem Performance" Initiative (e18e)](https://www.wearedevelopers.com/events/world-congress-2026-europe-virtual-stage/sessions/1521-de-bloating-the-web) — Ulrich-Matthias Schäfer
- [Azure-Well Architected Framework - Cost Optimization in practice](https://www.wearedevelopers.com/events/world-congress-2026-europe-virtual-stage/sessions/1495-azure-well) — Paweł Siwek
- [Why Is Software Documentation Still Static – And Why Modern Browsers Deserve Better](https://www.wearedevelopers.com/events/world-congress-2026-europe-virtual-stage/sessions/1644-why-is-software) — André Dietrich, Jihad Hyadi
- [Practical performance tuning for Serverless Java on AWS](https://www.wearedevelopers.com/events/world-congress-2026-europe-virtual-stage/sessions/1587-practical) — Vadym Kazulkin