Arkadiusz Ostrowski

Software Engineer · Full-StackTypeScript · React · Node

I build production AI-native software end-to-end.

Six years building production software, the last two shipping AI features: a research tool at Noah Media Group in 2023 (GPT-3.5/4) and a social-proof engine at GrowthNation in 2026 (Vercel AI SDK, Anthropic, OpenAI, a custom MCP layer).

The most recent build I'm proudest of is the code factory, co-built with the CTO: a pipeline of skills, plans, worktrees and automated gates that let a designer and a junior dev pick up tickets and ship straight to production. It cut engineering costs by more than 30%.

Career-changer: ten years in sales across Poland and the UK before self-teaching into software.

Open to senior engineering roles · London, UK
//experience
Product Engineer
GrowthNation · Contract (12 months)
2025 Jul – 2026 Jun · London, UK · Remote

Founding-team engineer on a social-proof OS for sales teams, through a CEO-driven pivot.

  • Joined during the initial product build for marketing function, helping SME's and Agencies streamline their AIO/SEO tactics, I built user auth, custom integrations and setup "code factory" workflow with the CTO to enable build contributions from all team members (product/design)
  • Built the Proof Library: ingestion (domain scrape, file upload, AI-vision screenshot extraction), dashboard with coverage matrix, and MCP/agentic access.
  • Server-side LLM tagging, every new quote, stat, or case study was tagged against the workspace's ICPs and pain points before save returns, with fan-out re-tag on edits.
  • Co-created an autonomous AI bug-triage system that performs root-cause analysis (temporal ordering, source prioritisation, fingerprinting, cascade detection) and opens clean fix PRs with plans and implementations on its own.
TypeScriptReact 18SupabaseVercel AI SDKMCP servers
ViteTailwind CSSDrizzle ORMBullMQOpenAIAnthropic ClaudeOpenRouterDeepSeekLangfuseElevenLabsFly.ioDockerCypressVitestPostHogSentryBetter Stack
Lead Product Engineer
Noah Media Group · Full-time
2025 Apr – 2025 Sep · London, UK · Hybrid

Promoted to lead as the sole remaining technical IC after the CTO's departure, and iterated on the new product until the tech arm wound down.

  • Built the film production tracking platform: database design, problem definition, early prototypes.
  • Worked closely with the CEO and the former Skyscanner CTO, Bonamy Grimes on prioritisation and stakeholder framing.
TypeScriptReactNodeExpressMongoDBBullMQOpenAI
Software Engineer
Noah Media Group · Full-time
2022 Apr – 2025 Apr · London, UK · Hybrid

First engineer in NMG's newly formed tech arm, building two products from scratch over three years.

  • SlateIQ: film success prediction. Combined IMDB, social, piracy, and market data into a comp-matching tool used in pitch decisions.
  • AI-powered research assistant on GPT-4 in 2024. Integration tests ran live LLM calls with graded responses to hold output to a bar, before checking LLMs in CI was common.
  • Established currying-based dependency injection as a team pattern, saving us from elaborate testing effort
TypeScriptReact 17Node.jsMongoDBOpenAI (GPT-3.5 + GPT-4)
Redux Toolkit + RTK QueryTanStack QueryMaterial UIstyled-componentsExpressBullMQIMDB GraphQLMusoAudienseSocialBladeDemographicsPROCheerioPuppeteerHerokuGoogle CloudAWSRedisJestCypressSentryWinstonGitHub Actions
Software Developer
Connect4 · Full-time
2020 Nov – 2022 Apr · London, UK · Remote

B2B SaaS for online-meeting productivity. Hired as the first employee developer to take over after the initial contract prototype build.

  • Ported the error prone Blaze front-end to React, reducing frontend error rate roughly by 30% and without breaking production.
  • Internalised unidirectional data flow and reactive DB-driven background refresh patterns to eliminate backend/frontend data sync issues
  • Built agenda creation feature with drag-and-drop and recurring meeting templates.
Meteor.jsBlazeReactWebSocketsMongoDB
JavaScript Developer
Wutzu Technologies · Full-time
2020 May – 2020 Nov · London, UK · Hybrid

"Deliveroo for small independent London shops." Hired as the second of two engineers on the product.

  • Refactored the MVP codebase and shipped the first production stores panel.
  • Built order and basket flows with external payment-API integration.
JavaScriptReactNodeFirebaseReduxWebpackPayments API
Web Developer
Self-employed · Freelance
2018 Sep – 2020 May · London, UK · Remote

Community sites and paid client work, through the London Java Community.

  • Built websites for the London Java Community and Meet a Mentor (referenced by Martijn Verburg and Simon Maple).
  • Mentored junior developers into their first software roles via LJC, having started as a mentee in the same community.
  • Took paid client work including the LJC Unconference site and a project for RecWorks (Barry Cranford).
HTML5CSS3JavaScript
//skills
AI / LLM
Vercel AI SDKOpenAIAnthropic ClaudeOpenRouterDeepSeekLangfuseModel Context Protocol (custom MCP servers)LLM-in-the-loop integration testingFirecrawlElevenLabsAI-assisted product development
Frontend
ReactNext.jsTailwind CSSRadix UIshadcn/uiTanStack QueryZustandRedux Toolkit + RTK QueryViteReact RouterTipTapFramer MotionRechartsThree.js (R3F + drei)
Languages
TypeScriptJavaScriptSQLJava (early-career)
Backend
Node.jsExpressBullMQRedisWebSocketsDrizzle ORMZodPuppeteerCheerioSharp
Databases & Data
PostgreSQLSupabase (Auth, Storage, Realtime, Edge Fns)MongoDBUpstash Redispgvector-ready architectures
Infrastructure & DevOps
VercelCloudflareFly.ioHerokuAWSGoogle CloudDockerGitHub ActionsSupabase preview branchesBlue-green deploysCron / scheduled jobsSlack/PostHog/Sentry alerting
Testing & Quality
VitestJestCypressPlaywrightSupertestTesting LibraryLLM Integration TestsESLint (custom in-repo rules)Huskylint-stagedKnipStorybook
Practices & patterns
Functional programmingCurrying-based dependency injectionPorts-and-adaptersTDD"Agent skills produce data" patternPay-on-success cost trackingAI-assisted programming
Observability & Product Analytics
SentryBetter Stack / LogtailWinstonPostHogGA4Meta PixelGoogle Search Console
Integrations shipped against
HubSpotPaddleNotionSlackWordPress (custom plugin)MailchimpDataForSEOIMDB GraphQLMusoAudienseSocialBladeCloudflare TurnstileTremendous
//testimonials
“
Arkadiusz is a strong self-starter who is diligent and righteous when it comes to building product, but measured and pragmatic about delivery so doesn't allow himself to get pulled into over-engineering. He is an excellent team-member capable of learning quickly and mentoring those around him. His focus and selfless drive mean I would happily recommend or work with him again.
Ben Ritchie
Hands-on CTO · GenAI/ML Product Specialist
“
Arkadiusz was amazing to work with, our community liked Arkadiusz's work so much that our hosting bandwidth needed to be readjusted to traffic demand twice the following day!
Martijn Verburg
Principal Engineering Group Manager at Microsoft
“
Arkadiusz worked very well in a team to gather requirements very accurately and turn them into visual results with a very fast turnaround. Arkadiusz is someone who gets the job done.
Simon Maple
Head of Developer Relations at Tessl
“
Arkadiusz was a pleasure to work with on our latest web project. He instantly had an appreciation for what we wanted to achieve… took initiative too… he wouldn't say no or find alternative solutions, instead he took the time to research what would be necessary to give us what we wanted.
Barry Cranford
Founder of RecWorks (Tech Talent Agency, London)
“
Developing good code is a mix of diligence, understanding the use case and good communication. In working with Arkadiusz I was able to see that he excels in each of these areas. He is able to work very well with a team, collaboratively and productively arguing a point when needed.
David McLeary
Group IT Development Manager at Greencore