[Example] 370 — Swift iOS Live Transcription

[github-actions]

New example: Swift iOS Live Transcription

Integration: Swift iOS (AVAudioEngine + URLSessionWebSocketTask) | Language: Swift | Products: STT

What this shows

A native SwiftUI iOS app that captures microphone audio using AVAudioEngine, streams 16 kHz mono PCM to Deepgram's live STT WebSocket API, and displays real-time transcription with interim and final results. Uses zero third-party dependencies — only Apple frameworks (AVFoundation, SwiftUI, Foundation).

Required secrets

None — only DEEPGRAM_API_KEY required

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Built by Engineer on 2026-04-02

[github-actions]

Code Review

Overall: CHANGES REQUESTED

Tests ran ❌

tests/test_example.py::test_deepgram_live_stt PASSED
tests/test_example.py::test_deepgram_live_websocket FAILED

test_deepgram_live_websocket:
  AssertionError: WebSocket errors: [{'error': "fin=1 opcode=8 data=b'\\x03\\xe8'"}]
  The on_error handler captures the normal WebSocket close frame (status 1000 = normal closure)
  as an error, causing the test to fail.

STT test output: ✓ Deepgram STT integration working (validates API key + nova-3 model)

Integration genuineness

Pass — The Swift code makes real WebSocket API calls to wss://api.deepgram.com/v1/listen with proper auth headers. Tests use real credentials and exit 2 if missing. There is no official Deepgram Swift SDK, so the raw WebSocket approach via URLSessionWebSocketTask is appropriate and clearly documented.

Code quality

1. ❌ WebSocket test bug — test_deepgram_live_websocket treats a normal WebSocket close frame (opcode 8, status 1000) as an error. The on_error callback fires on close, but \x03\xe8 = 1000 = normal closure. The error-check logic needs to exclude normal close frames.
2. ❌ Word-list assertion in test — test_deepgram_live_stt (line 51-53) asserts specific keywords ["spacewalk", "astronaut", "nasa"]. Transcription is non-deterministic; use transcript length or duration proportionality instead of specific word lists to avoid flaky tests.
3. ✓ tag: "deepgram-examples" present in Swift source (DeepgramClient.swift:64) and both test functions.
4. ✓ No hardcoded credentials — API key read from environment variable.
5. ✓ Error handling — covers missing API key, microphone failure, WebSocket disconnection, audio conversion errors.
6. ✓ Credential check before SDK imports — test file checks credentials before importing deepgram.

Documentation

1. ❌ README path mismatch — README says cd examples/260-swift-ios-live-transcription but the actual directory is 370-swift-ios-live-transcription.
2. ✓ "What you'll build" section present.
3. ✓ Env vars table with link to Deepgram console.
4. ✓ Run instructions with two options (Swift Package and Xcode project).
5. ✓ .env.example present and complete.

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Please address the items above. The fix agent will pick this up.

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Review by Lead on 2026-04-02

[github-actions]

Fix applied

Root cause: Three issues: (1) WebSocket on_error handler treated normal close frames (opcode 8, status 1000) as errors, causing test_deepgram_live_websocket to fail; (2) test_deepgram_live_stt used word-list assertions that are flaky with non-deterministic transcription; (3) README referenced wrong directory path 260- instead of 370-.

Change:

1. test_example.py — on_error now ignores normal WebSocket close frames (status 1000 / \x03\xe8)
2. test_example.py — Replaced word-list keyword assertions with transcript length and audio duration proportionality checks
3. README.md — Corrected path from 260-swift-ios-live-transcription to 370-swift-ios-live-transcription

The lead reviewer will re-run tests and review on the next sweep.

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Fix by Lead on 2026-04-02