CJ Cummings
Helping software companies ship profitable AI products | Co-founder/CEO @ Limitr | Ex-Siemens, Ex-Lockheed Martin
Boston, Massachusetts, United States of America
Artifacts
Limitr · Co-Founder & CEOAt Limitr, I set out to give AI product teams a way to control and monetize usage in real time instead of managing pricing and entitlements across scattered code and spreadsheets. I led the company building embedded infrastructure that enforces what users and agents can do while metering cost as it's incurred. I created Stof, the open-source Rust/WebAssembly runtime underlying this enforcement engine, and designed the policy-as-document model so pricing, limits, and entitlements live in one versioned, auditable document. I also built the real-time instrumentation that translates raw usage into visible, controllable value exchange data for our customers.
Stof · Creator & MaintainerI wanted data and logic to live together in one portable document instead of being split across config files, schemas, and interpreting code, so I designed and built Stof entirely in Rust, compiling it to WebAssembly so it runs natively, in the browser, or from Python. I built a lean, single-threaded cooperative async VM core with sandboxed execution, so logic arriving over the network can run in the same call without ever touching the filesystem or network itself. I also designed a document format that's a superset of JSON with formal definitions for functions, types, and units with conversions, working natively with YAML, TOML, PDFs, images, and other formats. I've grown and maintained the open-source project to over 500 commits.
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Leave a testimonialWork history
Feb 2026 - Present · 9 months · Co-Founder & CEO
Jan 2024 - Present · 2.8 years · Creator & Maintainer
May 2024 - Feb 2026 · 1.8 years · Co-Founder & CEO
Apr 2024 - May 2024 · 2 months · Founder in Residence
Nov 2023 - Mar 2024 · 5 months · Founder
Dec 2022 - Oct 2023 · 11 months · Software Architect - R&D
May 2021 - Nov 2022 · 1.6 years · Software Engineer 3
Mar 2020 - May 2021 · 1.3 years · Senior Software Engineer
May 2016 - Mar 2020 · 3.9 years · Software Engineer - R&D, Software Engineer Intern - R&D, Application Consultant Intern
May 2015 - Aug 2015 · 4 months · Computer Engineer Intern
May 2014 - Aug 2014 · 4 months · Controls Engineer Intern
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