Member of Technical Staff, Core Backend

Vapi

$130K — $180K *
Information Technology
Less than 5 years of experience
Job Overview by Ladders

Qualifications

  • 5+ years of experience in producing real-time or streaming systems for production environments.
  • Strong opinions on queue architecture involving BullMQ, Kafka, and Temporal.
  • Experience in building plugin or adapter architectures with decoupled implementations.
  • Proven operational expertise with Postgres at high scale and knowledge of connection pooling.
  • Skilled in instrumenting systems with OpenTelemetry, focusing on event-driven tracing.

Responsibilities

  • Ramp up on the StreamModule pipeline and cork/uncork backpressure model within the first month.
  • Analyze and address historical database incidents from Oct 15 and Oct 22 for future prevention.
  • Own the consolidation of BullMQ into Kafka by the end of 60 days.
  • Implement event-driven OTEL instrumentation for critical pipeline stages within 60 days.
  • Harden provider plugin paths to enable new model integration without core changes by day 60.
  • Drive measurable improvements in reliability or latency on the call path by the 90-day mark.
  • Participate in design reviews for new providers and pipeline changes as the backend owner.

Benefits

  • Competitive salary and excellent equity ownership.
  • Comprehensive health coverage including medical, dental, and vision plans.
  • Quarterly off-sites to promote teamwork and camaraderie.
  • Flexible time off policy allowing employees to take what they need.
  • Catered meals, transportation support, gym access, and an annual $10k learning and development budget.
Full Job Description


Why We're Hiring This Role:

The StreamModule pipeline - VAD 12 STT 12 LLM 12 TTS 12 Transport - runs on cork/uncork backpressure during live phone calls. A hundred milliseconds of delay is audible. This role owns pipeline stability and pluggability, so the agents and FDE teams can add new models and providers without touching core.

You'll consolidate BullMQ into Kafka, harden the provider abstractions (LLM, STT, TTS base classes), instrument the pipeline with event-driven OTEL tracing, and shore up the Postgres SPOFs that contributed to the Oct 15 and Oct 22 incidents.

What You'll Do:

30 Day: Ramp on the StreamModule pipeline and the cork/uncork backpressure model. Walk the Oct 15 / Oct 22 DB incidents and the duplicate-message incident. Land a scoped pipeline or provider-abstraction improvement.

60 Day: Own a slice of the BullMQ 12 Kafka consolidation. Ship event-driven OTEL instrumentation for at least one critical pipeline stage. Harden one provider plugin path so a new model can be added without core changes.

90 Day: Drive a measurable reliability or latency win on the call path. Be the backend owner that agents and FDE teams pull in for design reviews on new providers and pipeline changes.

Who You Are:

Must-haves:
  • You've built real-time or streaming systems in production - media pipelines, streaming data, or event-driven backends. You've debugged a backpressure cascade.
  • You have opinions on queue architecture (BullMQ, Kafka, Temporal) and when each is the right fit.
  • You've built plugin or adapter architectures - extending base classes cleanly, with decoupled implementations.
  • You've operated Postgres at scale: connection pooling, read replicas, schema migrations (Liquibase or similar).
  • You instrument with OpenTelemetry and think in event-driven traces, not just logs.


Nice-to-haves:
  • TypeScript + Node.js + NestJS. The codebase is huge NestJS, but a strong systems-thinking engineer ramps fast - language doesn't gate the hire.


Tech stack you'll work in:
  • Languages: TypeScript on Node.js (primary).
  • Framework: NestJS (large codebase).
  • Pipeline: StreamModule (VAD 12 STT 12 LLM 12 TTS 12 Transport), cork/uncork backpressure.
  • Queues: BullMQ (current), Kafka (target - consolidation on roadmap), Temporal.
  • Database: Postgres (connection pooling, read replicas), Liquibase for schema migrations.
  • Plugin system: provider abstractions - LLM, STT, TTS base classes (pluggable, decoupled from model integrations).
  • Observability: OpenTelemetry tracing, event-driven instrumentation.


Where you likely come from:
A streaming or real-time platform (Discord, Slack, Zoom, Twitch, Mux, LiveKit), an ML-infra company (Modal, Baseten, Replicate, Together), or a pipeline/workflow shop (Temporal, Stripe Radar, trading systems).

Weak fit: backend engineer who's only built systems where users don't wait in real time (overnight jobs, reports, dashboards).

What We Offer:

Real stake: We offer a competitive salary and excellent equity ownership

Comprehensive health coverage: medical, dental, and vision plans

Team love: We love hanging out, and we do quarterly off-sites

Flexible time off: take what you need

More: catered meals, transportation, gym, and a $10k annual L&D budget

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