Björn Stiel
Partner At Xltrail, Version Control For Excel at xltrail
London, England, United Kingdom
Summary
🤩
Rockstar🎓
Top SchoolBjörn Stiel is a pragmatic technologist and entrepreneur with 12+ years blending quantitative finance and developer-focused tooling, currently serving as Partner at xltrail, which brings Git-style version control to critical Excel workflows used by quants, traders and asset managers. He leverages a rare mix of hands-on trading and quant experience from UBS with deep Python and tooling expertise gained through consulting, education, and projects like celery.school and distributedpython.com. Based in London, he has repeatedly translated high-stakes financial requirements into auditable, production-ready software—reducing operational spreadsheet risk for pension risk transfer and asset management teams. Björn’s background in financial engineering and business economics informs a product-first approach that prioritizes traceability and reproducibility over flashy features. Colleagues know him for turning messy Excel-driven processes into disciplined, Git-integrated workflows that survive audits and market stress.
12 years of coding experience
11 years of employment as a software developer
MSc, Financial Engineering, MSc, Financial Engineering at Birkbeck College, University of LondonMSc, Business Economics, MSc, Business Economics at Freie Universität Berlin
English, German, Portuguese
Stackoverflow
4,013reputation
1.7mreached
48answers
2questions
docker-compose
top-1%
celery
top-5%
excel
top-5%
docker
top-1%
Github Skills (93)
python10
google-sheets10
excel10
xls10
xlwings10
docker-compose10
task-scheduler10
queue10
git-diff10
xlsx10
vba10
task-queue10
distributed-lock10
docker10
redis10
Programming languages (3)
Github contributions (5)
xltrail/git-xl
Feb 2018 - Aug 2019
Git extension: Makes git-diff work for VBA in Excel workbooks (xls* file types)
Contributions:16 releases, 116 commits, 6 PRs in 1 year 6 months
git-extensionxlsxxlsfile-typesvba
bstiel/airpollutionpi
Dec 2018 - Mar 2019
Raspberry Pi Mobile Air Pollution Monitoring System
Contributions:51 commits, 1 PR, 39 pushes in 3 months
raspberry-piraspberryair-pollutionairsystem-monitoring
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