Senior Quality Systems Engineer (Release Automation)

Mixpeek; San Francisco (CA); On-site; USD 180,000 - 220,000; Full time

Benefits offered by this job

Equity

Benefits

Job summary

ComfyUI in San Francisco is seeking an engineer to build the testing and verification infrastructure that enables daily releases. You will define what “correct” means, implement gates, and automate coverage across real user journeys.

You’ll tackle combinatorial and visual correctness, non-determinism, and third-party node compatibility with CI pipelines. Expect high ownership, startup pace, and impact across the ecosystem.

Qualifications

• Have built testing or verification infrastructure that other engineers depended on.
• Have worked on a system where scripted test coverage was impossible, and did something smarter about it: property-based testing, fuzzing, simulation, generative testing, or evaluation harnesses.
• Have shipped something that gates releases, and can tell us what happened the first time it blocked a launch.
• Are strong in TypeScript or Python, and comfortable in CI systems and build graphs.
• Have opinions about flakiness. You treat a flaky test as a defect with a root cause, not weather.
• Have a startup mindset: you thrive in fast-moving environments, take ownership, and love solving problems at scale.

Responsibilities

• Own what "correct" means for ComfyUI, and build the systems that prove it. Release gates, coverage of real user journeys, and the automation that makes shipping daily safe rather than scary.
• Solve the combinatorial problem. Users combine 60,000+ community nodes freely. Design property-based and generative testing that finds breakage in workflows nobody has written yet.
• Solve the visual correctness problem. Canvas rendering, node layout, and link routing break in ways pixel diffs can't catch without drowning you in false positives. Build perceptual comparison that engineers actually trust.
• Solve the non-determinism problem. Model output shifts with seeds, hardware, and drivers. Build the evaluation harness that separates a real regression from acceptable variance.
• Build custom node CI. Our ecosystem is our moat and our largest untested surface. Make third-party node compatibility something we verify continuously, not discover from bug reports.
• Use AI agents aggressively, and verify their output. Agent-driven exploratory testing, generated test cases, self-repairing suites - all of it, gated behind checks that reject the majority of what the agents produce.
• Make quality legible. Publish the metrics that tell us whether we're getting better, and own them in front of the team.

Skills

TypeScript

Python

CI systems

Tools

Playwright

Vitest

Storybook

Codecov

Job description

ComfyUI in San Francisco is seeking an engineer to build the testing and verification infrastructure that enables daily releases. You will define what “correct” means, implement gates, and automate coverage across real user journeys.

You’ll tackle combinatorial and visual correctness, non-determinism, and third-party node compatibility with CI pipelines. Expect high ownership, startup pace, and impact across the ecosystem.