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Engineering

Voice and Messaging Engineer

Full-timeRemoteReports to: Founder and Chief Executive Officer

Own the calls and texts at the heart of our work: missed-call follow-up, call routing and the owner’s approval texts.

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About SpareBrains

SpareBrains helps small and medium-sized businesses run better. A team of people and AI agents does real work for them. It finds where they’re losing customers online, fixes it, and keeps it running week after week. Our agents work inside our clients’ own accounts and tools, always with the owner’s approval. That makes trust the heart of what we sell.

The role

Phone calls and texts are where small businesses win or lose customers, and where owners say yes to our work. You’ll own the systems behind them: missed-call follow-up, call routing, voice agents and the approval texts. You’ll make them fast, dependable and compliant.

What you’ll do

Voice

  • Build and tune voice agents: speech to text, text to speech, turn-taking, interruptions and latency.
  • Route calls the way each business needs, without breaking their answering service.
  • Debug carrier and phone-line problems from call traces.

Messaging

  • Build text delivery that retries safely and never sends twice.
  • Run approval texts and missed-call follow-ups, with shared state across calls and texts.
  • Own business texting registration (A2P 10DLC), consent records and opt-outs under the TCPA.

Quality

  • Test calls and texts before release, with simulated conversations and regression checks.
  • Measure delivery, latency and outcomes, and improve them.

Example projects

  • A missed-call text that goes out within seconds from the owner’s own number.
  • Trying a new transcriber quietly on real calls before switching over.
  • A follow-up that stops the moment a customer replies or books.

What you’ll bring

  • 3+ years in backend engineering, with at least 2 in voice, telephony or messaging.
  • Python, TypeScript or Node.
  • Hands-on work with telephony and messaging APIs, and with voice agent frameworks.
  • Care about compliance: consent, opt-outs and carrier rules.

You don’t need every item on this list. If the work excites you, apply anyway.

Nice to have

  • SIP trunking, phone numbers and business phone systems.
  • WebRTC.
  • Packet capture and other call debugging tools.
  • Voice work in Spanish.

What we offer

A competitive base salary, equity, and the chance to build SpareBrains from its first day.

How to apply

Send your name, your email and your resume, with links to your work if you like. No cover letter needed.

Apply

Interview process

  1. Intro call. 30 minutes with our founder on the role, your work and your questions.
  2. Role interview. A deeper conversation about how you’d do the job, and the work you’ve done.
  3. Working session. We work through a real problem together, with any tools you like, AI included.
  4. References and offer. We speak to people you’ve worked with, then send the offer in writing.