Senior full-stack engineering that holds up.
TypeScript · Node.js · Python/FastAPI · React
with rare depth in API infrastructure
OpenAPI · AsyncAPI · Arazzo · Overlay · JSON Schema
17+ years full-stack. The last 7 also inside the spec ecosystem.
- Senior engineering & leadership roles at Oracle, SmartBear, Ubiquiti Networks, SecurityScorecard
- Principal Engineer at Apiary (acquired by Oracle)
- 5 years maintaining Swagger open source tools at SmartBear
- Maintainer of the AsyncAPI spec · GitHub Stars alumnus
I ship product code, and I build API tools for developers and AI agents alike.
Sound familiar?
Four kinds of engagements.
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Custom backend & full-stack
TypeScript / Node.js · Python / FastAPI · React, owned end to end
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Developer tooling
Parsers, validators, language services, CLIs, editor extensions
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Spec infrastructure
OpenAPI / AsyncAPI / Arazzo adoption, migrations, drift fixes
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Advisory
A straight answer on whether a spec, tool, or migration fits your team, before you commit
“Impressed us with his ability to plan large-scale initiatives, craft robust technical architectures, and deliver at speed.”
The buying decision, honestly.
A months-long recruiting cycle for a permanent seat. I start in days, for exactly as long as the work needs.
Vendors sell you their roadmap. I build around your workflow, in open standards, so nothing locks you in.
Most seniors have used OpenAPI. I've spent 7 years maintaining the tools your team depends on.
“A rare depth of knowledge and practical experience with standards such as OpenAPI and Arazzo.”
weekly npm downloads across the libraries I maintain
Chances are your build already runs my code.
- SpecLynx
- Open, local-first toolchain for API specifications · speclynx.com
- UseArazzo
- Toolkit for Arazzo API workflows · usearazzo.com
- SwaggerExpert
- Parsers & validators for the OpenAPI ecosystem · swaggerexpert.com
- RFC impls
- JSONPath (RFC 9535), JSON Pointer (RFC 6901)
Everything open source. Inspect my work before you hire me.
→ github.com/char0n
Simple. B2B. Low-friction.
- Shapes
- Project-based, or fractional (typically 15–25 hrs/week)
- Capacity
- 1–2 clients at a time: you get depth, not a slice of attention
- Where
- Remote, or hybrid in Prague
- Contract
- B2B via Czech IČO 05284503
- Start
- A short scoping call, or a paid audit of your existing spec setup
“One of the strongest engineers I've worked with.”
Tell me what you're trying to ship.
30 minutes, no pitch. Bring the problem. You'll leave with a straight read on scope, approach, and fit.
“He moved fast without hand-waving away the difficult bits. I'd hire him in a heartbeat.”