Job Title

Voice AI Scheduling (Scale‑Ready, Multi‑Tenant) — RemoteCompany: Apex Dental SystemsLocation: Remote (must overlap 7+ hours with 8am–5pm Pacific / America‑Vancouver)Type: Full Time Engineer with ramp up into CTOCompensation: Engineer: $2000USD/month + 1% equityUpon promotion to CTO: $4000USD/month + 2% equityAbout UsApex Dental Systems builds voice AI reception for dental/orthodontic clinics. We connect real phone calls (Retell AI + telephony) to booked appointments via NexHealth and, over time, direct PMS connectors. We’re moving from pilot to scale across 50–100+ clinics with high reliability and tight cost control.The MissionOwn the scale‑ready backend platform: multi‑tenant onboarding automation, secure configuration management, rate‑limit and retries, SLO‑backed reliability, cost observability, and compliance (HIPAA/PIPEDA). Your work allows us to onboard dozens of clinics per week with minutes, not days, of setup.Outcomes You’ll Deliver in the First 4–6 WeeksMulti‑tenant architecture with tenant isolation, role‑based access (RBAC), and per‑clinic secrets (env‑less runtime or AWS Secrets Manager).Onboarding automation that reduces per‑clinic setup to ≤60 minutes: provider/location/appointment‑type sync, ID mapping, test calls, and health checks.Hardened tool endpoints used by the voice agent (Retell function calling): availability_search, appointment_book, appointment_reschedule, appointment_cancel, patient_find_or_create, note_create, warm_transfer.Reliability controls: idempotency keys, timeouts, retries with backoff, circuit breakers; graceful fallbacks + warm transfer.Observability & SLOs: structured logs, metrics, tracing; dashboards for p50/p95 latency, error rates, booking success %, transfers, cost per minute/call; alerts to Slack.Security & compliance: PHI minimization, at‑rest and in‑transit encryption, access logging, data‑retention policy, BAA‑aware configuration.Cost guardrails: per‑tenant budget meters for voice minutes/LLM/TTS usage and anomaly alerts.KPIs you’ll move:Median tool‑call latency (p95 ≥ 80% booking/reschedule success without human handoff (eligible calls)99.9%+ middleware availability tool‑level error rate (after retries)≤ 60 min time‑to‑onboard a new clinic (target 30 min by week 6)ResponsibilitiesDesign, implement, and document multi‑tenant REST/JSON services consumed by the voice agent.Integrate NexHealth now; design extension points for direct PMS (OpenDental/Dentrix/Eaglesoft/Dolphin) later.Build sync jobs to keep providers/locations/appointment types up‑to‑date (with caching via Redis, invalidation, and backfills).Implement idempotent booking flows with conflict detection and safe retries; log every state transition.Stand up observability (metrics/logs/traces) and alerting; define SLOs/SLA and on‑call basics.Ship CI/CD with linting, tests (unit, contract, integration), and minimal load tests.Enforce secrets management, least‑privilege IAM, and a clean audit trail.Partner with our conversation designer to refine tool schemas and edge‑case flows (insurance screening, multi‑location routing).Mentor a mid‑level engineer and coordinate with ops for smooth rollouts.Minimum Qualifications5–8+ years building production backend systems (you’ve owned a system in prod).Expert in Node.js (TypeScript) or Python (FastAPI/Nest/Express).Deep experience with external API integrations (auth, pagination, rate limits, webhooks).Postgres (schema design, migrations) and Redis (caching, locks).Production reliability patterns: retries/backoff, timeouts, idempotency, circuit breakers.Observability: metrics, tracing, log correlation; incident triage.Security/compliance mindset; comfortable handling sensitive data flows.Strong written English; crisp architectural docs and PRs.Nice‑to‑HaveRetell AI (or similar voice/LLM with function calling and barge‑in), Twilio/SIP.NexHealth or other healthcare scheduling APIs; PMS/EHR familiarity.HIPAA/PIPEDA exposure, SOC 2‑style controls.OpenTelemetry, Prometheus/Grafana, Sentry; AWS/GCP; Terraform; Docker/Kubernetes.High‑volume, low‑latency systems experience.Our Stack (target)Runtime: Node.js (TypeScript) or Python (FastAPI)Data: Postgres, RedisInfra: AWS (ECS/EKS or Fargate), Terraform, GitHub ActionsIntegrations: Retell AI (voice), NexHealth (scheduling), Twilio/SIP (telephony)Observability: OpenTelemetry + Prometheus/Grafana or Cloud provider equivalentsHow We WorkRemote‑first; async‑friendly; 4+ hours overlap with Pacific time.Code in company repos, NDAs/PIAs/BAAs, DCO/CLA, and strict access hygiene.We optimize for reliability and patient privacy over quick hacks.Interview Process (fast, 7–10 days)Intro (20–30 min): Your background, past scale/reliability wins.Take‑home (90 min, paid for finalists):Implement availability_search + appointment_book against a stubbed NexHealth‑like API.Include idempotency keys, retries with backoff, timeouts, and basic tests.Provide a short runbook and a dashboard sketch for p95 latency & error‑rate alerts.Deep‑dive (60 min): Review your code; discuss multi‑tenant design, secrets, SLOs, and cost control.Final (30–45 min): Collaboration & comms.How to ApplyEmail info@ with subject “Senior Backend — Scale‑Ready Voice AI” and include:CV + GitHub/portfolio5–10 lines on a system you made multi‑tenant (what changed?)A time you prevented double bookings or handled idempotency at scaleYour preferred stack (Node+TS or Python), availability, and comp expectations