Senior Python Developer - FastAPI/Flask

Senior Python Developer Voice AI, Telephony & Real-Time Systems

About the Role :

We are building an AI receptionist and ambient assistant platform that answers and routes calls, books appointments, summarizes conversations, and provides real-time help inside calls. Youll design and ship backend services and real-time pipelines that power appointment scheduling, voice AI (ASR/TTS/LLM), transcripts & summaries, ambient assistance, vertical solutions (medical, property management, legal), third-party integrations (e.g., Toast, Jobber), and AI-assisted callflows.

What Youll Do :

Real-time voice/telephony services :

- Build Python microservices (FastAPI) for call control, presence, and routing.

- Implement SIP/WebRTC/RTP signaling & media handling, conference control, and callflow orchestration.

- Create low-latency streaming ASR pipelines and TTS playback; manage VAD, diarization, barge-in.

AI assistants & conversation intelligence :

- Integrate ASR/TTS/STT vendors (Whisper/Deepgram/Google/OpenAI, etc.) and LLMs.

- Ship summarization, action-item extraction, and RAG over knowledge bases/Content.

- Implement prompt safety, guardrails, evaluations, and fallbacks.

Appointment scheduling & personal assistant features :

- Build booking flows with Google/Microsoft calendars, availability, buffers, reminders, time zones.

- Capture/relay messages, human escalation, policy-based routing and SLAs.

Ambient assistance in live calls :

- Join/leave wake phrases; real-time IM/notes; add/remove participants; read knowledge on demand.

Vertical & partner integrations :

- Adapt flows for healthcare (HIPAA-aware intake, reminders), property management (tenant issues), and legal (intake & scheduling).

- Integrate with third parties such as Toast and Jobber via APIs/webhooks.

Platform engineering :

- Design resilient, observable systems (OpenTelemetry), queues/streams (Celery/Redis/Kafka), and data stores (Postgres/MySQL/Redis/Elastic/Vector DB).

- Own CI/CD, test coverage (pytest), load/soak testing, and production readiness.

- Collaborate with Product, QA, and Ops for staged rollouts and SLO- driven operations (latency, accuracy, uptime).

Must-Have Qualifications :

- 3 to 10 years professional Python experience building production backends/microservices (FastAPI/Flask).

- Real-time systems : streaming I/O (websockets/gRPC), asyncio concurrency, low-latency design.

- Voice AI : integrated at least one ASR and TTS provider and orchestrated LLM calls; built summaries/transcripts at scale.

- Data & infra : SQL schema design (MySQL), caching (Redis), queues (Celery/Kafka), containerization (Docker), cloud deployment (AWS/GCP/Azure).

- Testing & observability : pytest, contract tests, performance profiling, metrics/logging/tracing.

- Security & compliance mindset : secrets management, PII handling, auditability; awareness of HIPAA/PCI/SOC2 controls.

Nice-to-Have :

- Telephony/RTC : hands-on with SIP/WebRTC/RTP, media servers/gateways (Asterisk/FreeSWITCH/Janus/Kamailio/OpenSIPS), conferencing, DTMF, transfers.

- LLM ops : prompt/version management, eval harnesses, cost/latency tuning, vector DBs (FAISS/PGVector/Weaviate).

- NLU/NLP pipelines (spaCy), structured outputs with Pydantic, tool-use/function-calling.

- Calendar & booking APIs (Google/Microsoft), CRM/Helpdesk (Salesforce, HubSpot, Zendesk).

- Event-driven design (outbox, idempotency, saga) and blue/green or canary rollouts.

- Frontend familiarity (TypeScript/React) to collaborate on operator consoles.

Tech Stack :

- Python 3.11+, FastAPI, Pydantic, asyncio; WebSockets/gRPC; SIP/WebRTC/RTP; Asterisk/FreeSWITCH/Janus/OpenSIPS; Redis, Postgres/MySQL, Kafka; Docker, Kubernetes;, Terraform; OpenTelemetry, Grafana; pytest.

Soft Skills :

- Bias to action, clear written and verbal communication, production pragmatism.

- Partner-friendly mindset for vertical integrations.

- Cross-functional collaboration with Ops/QA/Product and customer-facing teams.