Comfy develops and maintains open-source software centered on generative AI workflows, primarily through its core product, ComfyUI, a node-based application for building and managing AI-driven content creation pipelines. Backed by Craft Ventures.
About the role
Comfy lets people build creative workflows that combine open-source models running on our GPUs with paid APIs from model providers. Every run has a cost. Customers need to understand what they’re spending, and we need to charge accurately as models, prices, and products change.
What they're looking for
- Have built and operated billing or payments systems in production, with meaningful ownership of usage metering, credits, or consumption-based pricing
- Have integrated Stripe directly and worked through subscription changes, invoices, webhooks, and payment failures beyond the happy path
- Can reason carefully about money across distributed systems: idempotency, concurrent updates, reconciliation, rounding, and recovery after partial failure. You can explain how you found and prevented a real billing error
- Are a strong backend engineer with experience in relational data modeling and reliable APIs. You can learn our stack and work across services to solve a customer problem
- Care about the experience behind the numbers. You can explain technical tradeoffs to Finance, Product, and Support and use their feedback to build better systems
- Take ownership from problem definition through rollout and operation. You use AI development tools effectively and verify their output with the care that systems handling money require
More about this role
Comfy lets people build creative workflows that combine open-source models running on our GPUs with paid APIs from model providers. Every run has a cost. Customers need to understand what they’re spending, and we need to charge accurately as models, prices, and products change.
You’ll own the engineering behind that: how we meter usage, collect payments, manage credits and subscriptions, and protect against financial abuse. You’ll make billing dependable for customers and give the team the tools to launch new pricing models with confidence.
Our billing stack uses Go, PostgreSQL, Redis, Temporal, Stripe, and Metronome, alongside Python and Kubernetes across the broader platform. You’ll evolve an existing system, work across service boundaries, and take changes from design through production.
Capture usage reliably. Build metering for GPU compute and partner model APIs. Handle delayed events, retries, and partial failures so every billable event is recorded once and attributed to the right workspace.
Own the payment lifecycle. Improve checkout, subscriptions, credit top-ups, plan and seat changes, prorations, refunds, and failed-payment recovery. Keep Stripe, Metronome, and our...
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