Browser-local practice backend

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@tony2037 is already working on this.

Since Nov 8, 2026.

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Description

I have a working Windows/Edge prototype that approaches #330 from the browser side. Would this be welcome as an optional Practice + Editor backend?

Design

  • Run interviewer turns through the browser's LanguageModel Prompt API, using the current problem, code, recent conversation and actual test results as context.
  • Recognize English speech on device, using native local recognition or a checksum-pinned Whisper WASM worker. Use installed local voices for replies.
  • Reuse the existing transcript, test runner and report UI. Store clearly labelled, unverified practice feedback only in device history.

Benefits

  • No Gemini API key or additional inference server to configure.
  • Model inference and speech recognition stay on the user's device.
  • Model, speech, report validation and UI integration are separate ES modules, with no frontend build step.

Scope and evidence
This prototype supports Practice with Editor. LiveKit still transports media, and C/C++/Java execution still uses Compiler Explorer. Strict interviews, whiteboard assessment and server recording remain on the cloud path. Its simplified practice feedback does not implement the cloud assessment contract.

Windows/Edge has been exercised end to end. 327 targeted tests pass, including actual Whisper recognition with networking disabled. Chrome/Linux end-to-end validation and the complete gate remain pending; no quality or latency parity with Gemini Live is claimed.

Would you prefer this as a browser-local backend in CodeTrial, or an out-of-tree experiment alongside the server-side pipeline?

Also see:

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Rust
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