Member of Technical Staff, Core Backend

Vapi

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

Qualifications

  • Experience building real-time or streaming systems in production environments.
  • Strong understanding of queue architectures like BullMQ and Kafka.
  • Proven ability to design plugin or adapter architectures effectively.
  • Experience operating Postgres at scale with connection pooling and read replicas.
  • Familiarity with OpenTelemetry for observability and event-driven tracing.

Responsibilities

  • Ramp on the StreamModule pipeline and analyze recent database incidents
  • Drive a consolidation effort of BullMQ into Kafka.
  • Implement event-driven instrumentation using OpenTelemetry for critical pipeline stages.
  • Enhance provider plugin paths to allow for new model integrations without core modifications.
  • Serve as the backend liaison for design reviews involving new providers and changes to the pipeline.

Benefits

  • Competitive salary and equity ownership
  • Comprehensive health coverage including medical, dental, and vision
  • Quarterly off-site team bonding events
  • Flexible time off policy
  • Catered meals, transportation subsidies, gym access, and a $10k annual learning and development budget
Full Job Description


Why We're Hiring This Role:

The StreamModule pipeline - VAD → STT → LLM → TTS → 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 → 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 → STT → LLM → TTS → 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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