Leo Ostera

Stockholm, Stockholm County, Czechia

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Summary

🤩

Rockstar

🎓

Top School

Leo Ostera is a product-minded software engineer and founder with 14 years of experience building developer tooling, systems, and data-driven applications across startups and larger tech firms. He has led engineering and product teams at companies like Spotify, Klarna, Walnut, and founded multiple companies including Abstract Machines and warp.build, blending hands-on engineering with strategic product leadership. Deeply involved in the OCaml ecosystem, he has contributed to the core OCaml compiler and shipped developer-facing projects such as a reactive tldr web client, demonstrating fluency in both backend type system work and front-end UX. Based in Stockholm with roots spanning Czechia and Colombia, he excels at forming diverse, empowered teams that focus on solving the right problems the right way. Known for refactoring complex compilation and build workflows, he pairs long-term technical vision with pragmatic delivery. Talk strategy to him—he enjoys translating big-picture goals into concrete engineering roadmaps.

14 years of coding experience

15 years of employment as a software developer

Informatic Engineer, Computer and Information Sciences, Informatic Engineer, Computer and Information Sciences at Universidad del Norte 'Santo Tomás de Aquino'

Swedish, Portuguese, Czech, English, Spanish

Github Skills (15)

type-system10

compiler10

sass10

javascript10

user-interface10

compiler-compiler10

functional-programming10

functional-programming-language10

react10

functional10

ocaml10

html9

css9

responsive-design9

url-routing8

Programming languages (32)

CSchemeMakefileGoHTMLErlangReasonPostScript

Github contributions (5)

leostera/tldr.jsx

Dec 2015 - Sep 2020

📚 A Reactive web client for tldr-pages

Role in this project:

Front-end Developer

Contributions:372 commits, 95 PRs, 273 pushes in 4 years 9 months

Contributions summary:Leo primarily focused on developing the front-end for the `tldr.jsx` project, a reactive web client for tldr-pages. Their contributions include fixing analytics tracking, implementing search bar functionality including routing, and improving the styling for mobile and desktop layouts. They also addressed issues related to UI elements and overall user experience.

web-clientreactivetldrtldr-pages

ocaml/ocaml

Nov 2020 - Nov 2020

The core OCaml system: compilers, runtime system, base libraries

Role in this project:

Back-end Developer

Contributions:3 reviews, 9 commits, 4 PRs in 1 day

Contributions summary:Leo contributed to the core OCaml system by modifying several files related to the type system and compilation pipeline. Their work involved exposing module signatures, introducing a `typed_impl` record for improved code organization, and refactoring code dependencies. These changes appear to enhance the type checking process and compilation workflows, potentially for new backends and overall system improvements. The user also fixed linting errors and addressed a typo in the code.

functional-languagecompilersruntime-systemapllwt

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