Justin Halsall
Core-team Member (available For Consulting Work) at rrweb.io
Amsterdam, North Holland, Netherlands
Summary
🤩
Rockstar🎓
Top SchoolJustin Halsall is a startup founder, open source maintainer, and software engineer with 14 years of experience building developer tools, developer relations, and resilient web products from Amsterdam. He co-created and maintains rrweb, the leading open-source web session record/replay library, and led DevRel for Kilo Code to the top of OpenRouter.ai while founding Record Once to automate product video docs. Equally at home in code and on stage, he’s MC’d and keynoted major conferences worldwide, bringing high-energy facilitation to technical audiences of thousands. His contributions span front-end test automation and back-end API documentation tooling, reflecting a hands-on approach to both UX and platform stability. Comfortable consulting across product, community, and engineering, he combines startup grit with proven open-source stewardship.
13 years of coding experience
20 years of employment as a software developer
IT Media, IT Media at Grafisch Lyceum Utrecht
English, Dutch, French
Stackoverflow
19reputation
0reached
1answer
0questions
Github Skills (17)
puppeteer10
javascript10
json-schema10
testing10
ruby10
api-documentation10
test-automation10
recorder9
erb9
front-end-development9
rest-api8
api-rest8
restful-api8
cgi8
api-design8
Programming languages (20)
Github contributions (5)
rrweb-io/rrweb
Aug 2020 - Jan 2023
record and replay the web
Role in this project:
Front-end Developer & Test Automation Engineer
Front-end Developer & Test Automation EngineerContributions:393 reviews, 199 commits, 231 PRs in 2 years 5 months
Contributions summary:Justin contributed to the rrweb repository by adding and improving regression tests for the replayer functionality. They implemented tests for features like pausing at specific time offsets and live mode streaming events. The user also addressed a bug related to removing style elements in the replayer. Their work focused on ensuring the correct behavior and stability of the web recording and replay functionality, particularly in the context of features like time manipulation.
reactreplayfullstoryrecord-and-replayrecord
interagent/prmd
Jul 2014 - Sep 2014
JSON Schema tools and doc generation for HTTP APIs
Role in this project:Back-end Developer
Back-end DeveloperContributions:24 commits in 2 months
Contributions summary:Justin focused on enhancing the documentation generation capabilities of the API documentation tool. They implemented features to generate documentation for nested objects within arrays, refined the example generation by adjusting how values like hashes and enums are displayed. Additionally, the user refactored the URL generation process into subclasses and added support for generating GET parameters for different URL styles.
jsonapiapijson-schemahanamijson
Find and Hire Top DevelopersWe’ve analyzed the programming source code of over 60 million software developers on GitHub and scored them by 50,000 skills. Sign-up on Prog,AI to search for software developers.