Jesse Brennan is a founding engineer based in San Francisco with 11 years of experience building production-ready web and mobile platforms, tooling, and backend systems. He has led engineering at early-stage startups, shipping offline-capable mobile apps, e-signature and cost-tracking features, and prioritizing rapid customer-driven iteration. Previously he contributed to open-source genomics infrastructure at the UC Santa Cruz Genomics Institute, becoming a core developer on Azul and a maintainer of the Toil workflow engine used in large-scale bioinformatics projects. Comfortable across backend, DevOps, and product-facing work, Jesse blends practical systems engineering with customer empathy to solve the right problems. Outside software he’s equally likely to be building something musical or hands-on in the real world, reflecting a maker mindset that surfaces in both code and product.
A scalable, efficient, cross-platform (Linux/macOS) and easy-to-use workflow engine in pure Python.
Role in this project:
Back-end & DevOps Engineer
Contributions:271 commits, 40 PRs, 185 pushes in 1 year 8 months
Contributions summary:Jesse's contributions primarily focused on improving the Toil workflow engine's documentation, build process, and infrastructure support. The user added detailed installation instructions for Docker and included Quay account setup information for testing. They also improved Python 3 support, fixed argument parsing, and made modifications to facilitate tagging EC2 instances with user-specified tags. Additionally, they addressed file size retrieval and added tests for the results filename.
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