Johan Fylling
Software Engineer at Apple
Sweden
Summary
🤩
Rockstar🎓
Top SchoolJohan Fylling is a seasoned software engineer based in Sweden with over a decade of experience building secure, dependable systems across startups and established companies. He has held engineering roles at Curity, Styra, and now Apple, bringing deep expertise in developer tools, identity/security products, and backend systems. Johan is an active open-source contributor to high-profile projects like Open Policy Agent (OPA), where he implemented crypto and time-safe functions and tightened network/HTTP security edge cases. His work reflects a strong focus on security, correctness, and practical mitigations for subtle vulnerabilities such as time-related integer overflows and host allow-listing. Trained with a Master’s in Computer Software Engineering from Blekinge Tekniska Högskola, he blends academic grounding with hands-on product delivery. Colleagues describe him as meticulous about safety and reliability, often surfacing non-obvious edge cases before they reach production.
10 years of coding experience
17 years of employment as a software developer
Master of Computer Science and Enginering, Computer Software Engineering, Master of Computer Science and Enginering, Computer Software Engineering at Blekinge Tekniska Högskola
Stackoverflow
98reputation
11kreached
8answers
0questions
Github Skills (18)
authorizations10
gpo10
policies10
rule-engine10
go10
authorization10
cryptography10
hashing-algorithm10
security9
apidoc9
api9
azure6
abac6
glob6
rego6
Programming languages (12)
Github contributions (5)
open-policy-agent/opa
Dec 2021 - Jan 2023
Open Policy Agent (OPA) is an open source, general-purpose policy engine.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:1 release, 891 reviews, 29 commits in 1 year 1 month
Contributions summary:Johan primarily contributed to the development of built-in functions within the Open Policy Agent (OPA) project. They added and improved crypto and time-related functions, including HMAC functions for hashing algorithms and functions to prevent time-related integer overflows. The user also focused on security aspects, particularly around host allow-listing in the HTTP and network functions, as well as addressing edge cases and potential vulnerabilities. They also made important improvements and additions to support module functionality.
policycompliancedogepoliciescloud-native
StyraInc/styra-run-sdk-node
Jun 2022 - Dec 2022
Contributions:50 commits, 3 PRs, 5 pushes in 6 months
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