Senior Full Stack Engineer (Back-End)

About the role

This is a full-time, in-person role based in San Francisco (Presidio) - we work from the office 5 days a week. You must be based in the Bay Area or willing to relocate before starting. We require US work authorization, but are open to O-1 visa sponsorship for truly exceptional candidates.

Responsibilities

• Write and ship full-stack features end to end, from the agent runtime and backend APIs, to the web and desktop UI that users interact with every day.
• Make the decisions that determine whether this system holds at 1000x the current load.
• Work directly with the CTO on various projects such as:
• Building and operating the sandbox infrastructure where agents execute code, process isolation, resource limits, secure credential handling across thousands of concurrent sessions.
• Designing the deployment and migration pipeline for a Cloudflare Workers + Fly.io architecture, including blue-green rollouts and canary patterns.
• Instrumenting real-time workloads end to end: SSE streaming, task queues, and multi-model LLM provider routing.
• Shipping new backend capabilities, tool integrations, scheduled task execution, memory indexing, and seeing them used by real people the same week.
• Reducing operational toil for a small team: structured logging, tracing, monitoring, and incident response tooling that actually works at our scale.
• ${your ideas}.

Requirements

• You have 5+ years of engineering experience building and operating backend systems in production. You've been on-call.
• You're fluent in TypeScript and comfortable working across the stack, but your instinct is to go deeper on the backend.
• You've built real-time systems: WebSockets, SSE, event streaming, or message queues in production.
• You have distributed systems intuition, you understand consistency tradeoffs and have opinions about them.
• You've shipped infrastructure to real users, not just internal tooling.

Bonus (but not required)

• You've worked with Cloudflare Workers, Durable Objects, or serverless compute at the edge.
• You've built agent systems, model routing layers, or tool-use architectures with LLMs.
• You've been a founder or early-stage engineer and care deeply about product.

Skills

• TypeScript
• Cloudflare Workers
• Durable Objects
• Hono
• Drizzle ORM
• Postgres
• Zod
• SST
• Vercel AI SDK
• Docker
• React
• Vite

Pay

Base salary: $180K–$240K + meaningful early-stage equity + health, dental, 401(k).

Schedule

We keep our process simple. Exceptional candidates go from first touch to offer within 2 weeks.

Benefits

We provide a healthy work-life balance, respectful of time off and steady progress over late-night heroics.

About Wordware

Wordware is backed by Spark Capital, Felicis, and Y Combinator, with a $30M seed round. Our beautiful, historic San Francisco office sits in the shadow of the Golden Gate Bridge, it’s full of plants and radiates innovation and calm. We genuinely love working together. At lunch we talk about alignment and AI consciousness, we have surfboards in the office ready to use, we take walking meetings on the beach and hang out after work at the bar or climbing wall. We work really hard because we care deeply about what we do.

About Sauna

Sauna is Wordware’s AI workspace for professionals. Think ‘Cursor for Knowledge Work’ and you’re halfway there. With explicit permission, it connects to tools like Gmail, Calendar, Slack, and thousands more, to gather the right context to move your work forward. It learns who you are, drafts and refines your documents, presentations, and datasets, researches across the web and your org’s internal knowledge, summarizes long threads to cut through the noise, proposes next steps, even acts on your behalf when enabled. You can work with Sauna live, side-by-side, or schedule jobs to run automatically in the background, with clear permissions and easy off-switches.

Who thrives here?

People who like small, correct moves that compound. People who stay calm when the plan changes and make the next good decision without drama. People who treat constraints as design inputs, not roadblocks. If you’ve built something from scratch, carried it through the unglamorous parts, and kept your standards high, you’ll feel at home.