Software Engineer / Barcelona, Spain

Sergey
Rubanov

Engineering AI agent infrastructure, web platform tooling & developer tools, from specifications and engines to production systems.

Portrait of Sergey Rubanov
01

Profile

Software engineer and independent researcher working on AI agent infrastructure, the web platform, developer tooling, and open source.

Contributes to TC39 and W3C work on JavaScript semantics, browser behavior, conformance tests, and developer-facing APIs.

02

Core Skills

AI / agent systems agent orchestration tool execution evaluation harnesses provider routing OpenAI / Anthropic APIs llama.cpp MCP / ACP
Web platform / standards ECMA-262 ECMA-402 TC39 W3C Test262 WebAssembly JavaScriptCore WebKit browsers/webviews
Languages TypeScript Go C++ Zig Coq / Rocq
Platform / observability OpenTelemetry traces/metrics/logs Prometheus Grafana OTel Collector Docker Kubernetes Terraform AWS GCP Cloudflare
03

Selected Projects

Hecate

AI workspace / runtime

Local-first workspace for local and cloud AI models, project context, and supervised coding agents, with provider APIs, approvals, diff review, usage reporting, and OpenTelemetry.

Stack Go · TypeScript · React · Tauri · SQLite · OpenTelemetry

hecate.sh·github.com/hecatehq/hecate

Cynic

ECMAScript / WebAssembly engine

Strict-only ECMAScript and WebAssembly engine in Zig with frozen primordials, hardened realms, host-controlled code generation, and no Annex B.

Stack Zig · ECMAScript · WebAssembly · Test262 · WebAssembly testsuite

sergey.works/cynic·github.com/chicoxyzzy/cynic

Pragmatist

Reproducible verification

Research tool for proving bugs in ECMAScript specifications, TypeScript, JavaScript engines, and WebAssembly runtimes using pinned source data, Coq/Rocq mechanization, differential runs, patch scaffolding, and deterministic replay.

Stack TypeScript · Coq/Rocq · ECMA-262 · WebAssembly · tsgo · Zod

TC39 MCP

MCP server

MCP server for clause-level ECMA-262 and ECMA-402 search, cross-spec references, edition diffs, git history, Test262 and proposal lookup, and SHA-pinned local or hosted responses.

Stack TypeScript · ECMA-262 · ECMA-402 · Cloudflare Workers · VitePress · Zod

mcp.xyzzylabs.ai/tc39/·github.com/xyzzylabs/tc39-mcp

WASM MCP

MCP server

Read-only MCP server for WebAssembly specifications with instruction and clause lookup, opcode and stack-signature metadata, proposal search, and SHA-pinned local or hosted responses.

Stack TypeScript · WebAssembly · Cloudflare Workers · VitePress · Zod

mcp.xyzzylabs.ai/wasm/

04

Experience

Independent Software Engineer / Consultant

Barcelona

Sep 2025 — Present

Independent engineering and research across AI agents, web standards, developer tools, and open source.

  • Build local-first agent tooling for model access, supervised coding sessions, approvals, diff review, and telemetry.
  • Develop standards and conformance tools for ECMAScript, TypeScript, and WebAssembly, including source pinning and differential testing.
  • Contribute to TC39/ECMA-262 and Test262 by analyzing proposal trade-offs, refining specification text and semantics, and collaborating with browser vendors, JS engines, and the standards community.
  • Consult on agent architecture, developer tooling, observability, and deployment.

Invited Expert · TC39

May 2019 — Present
  • Co-authored the Promise.any proposal and contributed editorial improvements to ECMA-262.
  • Participate in proposal discussions, evaluate compatibility and ergonomics trade-offs, and develop Test262 tests to validate JavaScript behavior across engines.

Software Engineer · Firetiger

US · Remote

May 2024 — May 2025

Firetiger acquired Dispatch.run four months into the role.

Firetiger observability platform

  • Built product features and infrastructure for an OpenTelemetry-based observability platform.
  • Helped early customers instrument Python and TypeScript services and deploy integrations across Vercel, Kubernetes, and Terraform-managed infrastructure.

Stack Python · TypeScript · Node.js · Next.js · Vercel · Docker · Kubernetes · Terraform · AWS / GCP · OpenTelemetry · Prometheus · Grafana · OTel Collector

Dispatch.run durable functions platform

  • Owned the CLI workflow for local development, deployment, and handoff to cloud execution.
  • Evaluated running Go workloads as WebAssembly on Cloudflare.

Stack Go · WebAssembly · Cloudflare

Software Engineer · Socket Supply Co

US · Remote

Mar 2022 — Jan 2024
  • Developed core Socket Runtime components in C++ for execution, platform integration, and native capabilities.
  • Expanded JavaScript APIs for Node.js compatibility across mobile and desktop hosts.
  • Built tooling for project setup, local development, and runtime debugging.

Stack C++ / C / Objective-C++ · JavaScript / TypeScript · Node.js · WebKit- and Chromium-based webviews (WKWebView, libwebkit2gtk, WebView2)

Software Engineer · RealAdvisor

Geneva · Remote

Dec 2019 — Sep 2021
  • Developed a multi-tenant CRM and custom document editor with reusable layout templates.
  • Optimized the document rendering pipeline to improve load times and editor responsiveness.

Stack React / Svelte · Flow · Node.js · Relay · Docker + Composer · Headless Chromium · GCP

05

Earlier Experience

Frontend Developer Lead · EXANTE

Malta · Remote

Dec 2014 — Aug 2019
  • Led frontend development of a web trading terminal, browser extension, Ledger hardware-wallet apps, and cryptocurrency products.
  • Mentored and interviewed web developers while leading delivery across React/Preact, TypeScript, RxJS, D3, Redux/MobX, and browser-extension work.

Stack React/Preact · Redux/MobX · RxJS · D3 · TypeScript · C

Senior Developer · NPTV

Moscow · Russia

Oct 2013 — Nov 2014
  • Built a JavaScript SDK for an interactive TV platform, similar to React Native; helped adopt SpiderMonkey and later migrate to V8.
  • Maintained build tooling and DevTools extensions and prototyped client-side platform features.

Stack JavaScript · Babel · React · Chrome DevTools extensions

Frontend Team Lead · KM Media

Moscow · Russia

Sep 2012 — Jul 2013
  • Led frontend delivery for an advertising platform.
  • Introduced unit testing with Karma and Jasmine to improve regression coverage.
  • Worked with backend and product teams on integration and data-quality issues.

Stack Angular · JavaScript

Senior Developer · Comfortel

Oryol · Russia

Sep 2009 — Jul 2013
  • Built a CRM and integrations with Genesys Agent Desktop and Oktell for call-center workflows.
  • Promoted to Team Lead in 2012; led delivery of customer-interaction tracking and operator workflows.
  • Built a web-based operator-script generator for call-center teams.
  • Worked with MySQL, MSSQL, and Oracle databases for CRM data, reporting, and call-center integrations.

Stack PHP · JavaScript · MSSQL · MySQL · OracleDB

06

Education & Languages

Master of Computer Science · Oryol State Technical University

Oryol · Russia

2009

Languages — Russian (Native) · English (Proficient) · Spanish (Novice)