John Sully
Chief Executive Officer at Phasar Labs
Toronto, Ontario, Canada
Summary
🤩
Rockstar🎓
Top SchoolJohn Sully is a seasoned engineering leader and founder with 11 years of experience building high-performance systems, currently serving as CEO and co-founder of KeyDB and Phasar Labs in Toronto. A hands-on C++ developer and Microsoft alumnus, he has a track record of shipping performance-critical work—from rewriting text layout/rendering subsystems at Microsoft to leading FPGA/GPU accelerator efforts at EQ Alpha. John is an active open-source maintainer and contributor to major key-value projects (including fixes to the widely used Redis codebase), demonstrating deep expertise in database internals, replication, and data-structure corruption fixes. He combines product-level CEO experience with low-level systems craftsmanship, and uniquely bridges hardware acceleration and storage software to solve real-world scaling problems.
11 years of coding experience
18 years of employment as a software developer
White Oaks Secondary SchoolToronto Metropolitan University
Stackoverflow
1reputation
0reached
0answers
0questions
Github Skills (19)
key-value-store10
back-end-development10
nosql10
redis10
databases10
c1110
c1710
hyperloglog10
database10
package-development9
key-value9
debug9
plugin-development9
drupal-module9
caching7
Programming languages (8)
Github contributions (5)
valkey-io/valkey
Jun 2024 - Jan 2025
A flexible distributed key-value datastore that is optimized for caching and other realtime workloads.
Role in this project:
Backend Developer
Backend DeveloperContributions:3 reviews, 2 PRs, 37 comments in 7 months
Contributions summary:John primarily focused on fixing bugs and improving the stability of the ValKey datastore. Their contributions involved addressing corruption issues in the hyperloglog implementation and resolving an issue related to replica behavior. Additionally, the user implemented a feature to allow specifying an availability zone for the server and added checks for module execution permissions. These changes suggest a focus on core functionality and operational aspects of the database.
cachedatabasekey-valuekey-value-storenosql
redis/redis
Mar 2019 - Jan 2020
Redis is an in-memory database that persists on disk. The data model is key-value, but many different kind of values are supported: Strings, Lists, Sets, Sorted Sets, Hashes, Streams, HyperLogLogs, Bitmaps.
Role in this project:Back-end Developer
Back-end DeveloperContributions:16 commits, 12 PRs, 38 comments in 9 months
Contributions summary:John primarily focused on bug fixes and improvements to the Redis codebase. They addressed issues related to replica behavior, specifically preventing replicas from running the `replicaof` command. Additionally, the user fixed a hyperloglog corruption bug and implemented checks for module loading permissions. These changes directly impacted core functionality and stability of the database.
memorystreamsin-memory-databasememory-databasedata-model
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.