External Services

Integrated providers

• Google token verification service.
• OpenAI OCR extraction for receipts.
• OpenAI transcription + command normalization for voice input.

Service implementations

• Google auth: backend/src/Infrastructure/Services/GoogleAuthServiceImpl.ts
• OCR: backend/src/Infrastructure/Services/OcrServiceImpl.ts
• Voice: backend/src/Infrastructure/Services/VoiceServiceImpl.ts

Reliability behavior

• Timeout and retry wrappers are used for provider requests.
• AI outputs are parsed and validated before creating transactions.
• Multer handles multipart ingestion boundaries (audio, receipt) before requests reach AI services.
• Provider failures are translated into infrastructure-layer error codes.

Operational requirements

• GOOGLE_CLIENT_ID required for Google auth.
• OPENAI_API_KEY required for OCR/voice.
• Keep provider keys in platform secret manager, never in source code.