Vetted engineers with verified commercial track record in TypeScript
Khmelnytskyi, Ukraine
Full-Stack Developer, Fractional CTO — Websites, Apps, Servers, Databases, AI, SEO & QA
Full-stack developer working across the entire stack — websites, apps, servers, databases, AI integrations, SEO, and QA. Languages & Core: writes code in JavaScript, TypeScript, Python, PHP, Go, and Rust. Architects scalable systems for large-scale projects. Frontend & Interfaces: builds websites and web applications with React and Next.js. Crafts responsive interfaces with Tailwind CSS, Radix UI and Shadcn, adds smooth animations with Framer Motion, and interactive charts with Recharts. SEO Audit & On-Page Optimization: semantic keyword research, resolving technical indexing issues, and optimizing page load speeds. Structures page architecture, meta tags, and multi-language support (i18n). Copywriting & Content Strategy: writes technical articles, drafts precise content briefs for writers, and develops content plans. QA & Testing: full-cycle testing for websites, web services, and Android apps — manual QA for UI/UX and business logic, plus automated testing with Jest, Vitest, Playwright and E2E. Backend, Cloud & Databases: complex API integrations of any scale. Builds servers with Node.js (Express, Fastify). Works with PostgreSQL, MySQL and MongoDB, ORMs (Prisma, Drizzle), and cloud infrastructure (Supabase, Firebase, Cloudflare). Browser Extensions & Automation: develops Manifest V3 browser extensions for Chrome, Edge, Firefox and other browsers. Builds web scrapers for complex data extraction using Puppeteer and Playwright. AI & Intelligent Agents: builds custom AI agents and integrates LLMs from OpenAI, Google Gemini, and Anthropic Claude via API, including Claude Code setups. Servers & DevOps: Linux (Ubuntu) and VPS administration — setup, updates, real-time monitoring, secure process isolation, Nginx, PM2, and CI/CD deployment via GitHub Actions. Telegram Bots: develops advanced Telegram bots (Telegraf, Grammy) integrated with AI, payment gateways, Google Sheets, and crypto exchanges. Desktop Applications: builds cross-platform software for Windows and macOS using Electron and Rust. Additional expertise: site development and customization with WordPress and Astro.
Senior Frontend Engineer · React · Next.js · Angular | Open to new opportunities
Senior frontend engineer with deep experience across React, Next.js and Angular, building enterprise dashboards and complex UI systems. Strong focus on performance, component architecture and design-to-code fidelity.
Mügeln, Saxony, Germany (Saxony, Germany · Remote)
Full-Stack Engineer — TypeScript, React, Next.js, Node.js, PostgreSQL | Germany
Full-Stack engineer with 13+ years of technical experience, including 7+ years directly managing and administering production databases. Specializes in PostgreSQL relational schema modeling, slow-query optimization (EXPLAIN ANALYZE), relationship design, and data integrity via Prisma ORM and raw SQL. Designed a real-estate platform syncing 50K+ records in PostgreSQL and serving them through ~100 API endpoints.
Albertville, Auvergne-Rhône-Alpes, France (Albertville, France · Remote Europe / US)
Freelance Full-Stack Developer | Stripe Certified Implementation Architect | 10+ yrs building Laravel, PHP, Vue & React
Officially certified Stripe implementation architect (Stripe Certified Implementation Architect) and full-stack developer with 12+ years of commercial experience. Specializes in complex payment flows, Stripe Billing integration, subscriptions, webhook handling, custom checkouts, and customer self-service portals on Laravel, Vue, React, and TypeScript.
London, United Kingdom (London, United Kingdom · Hybrid)
Full-Stack AI Product Engineer | ex-CTO Pineapple Builder | PostgreSQL & Relational Architecture
Full-Stack engineer and ex-CTO of the Pineapple Builder platform with 11+ years of commercial experience. Personally designed and led the PostgreSQL relational database architecture for a full-featured site builder, ensuring high content throughput via a GraphQL API. As Member of Technical Staff at DevRev, built the Agent Studio agentic platform core and agent connections to tools and databases.
London, United Kingdom (London Area, United Kingdom · Remote)
Full Stack Engineer | ReactJS, NextJs, NodeJS, TypeScript, AWS & Java | Contractor
Senior Full-Stack contractor and solutions architect with 10+ years of commercial experience in FinTech, Buy Now Pay Later (BNPL), and e-commerce. At Deko, led the build and launch from scratch of an instalment fintech platform with £1.3M turnover. Designed a JavaScript plugin system for merchant site integrations based on React, Next.js, GraphQL, and Storybook, plus serverless backend infrastructure on AWS (Lambda, SQS, SNS).
London, United Kingdom (London Area, United Kingdom · Remote)
Principal Engineer | Senior Frontend Developer | React.js · Next.js · Tailwind CSS · GraphQL | Headless E-Commerce Specialist
Lead frontend architect with 10+ years of commercial experience building complex user interfaces and headless e-commerce platforms. At Chalhoub Group designed and shipped a modular reusable-component library on React.js and Tailwind CSS, reworked checkout and cart to lift conversion, and optimized interface performance and response times on mobile devices. Extensive experience with testing (Jest, React Testing Library), GraphQL (Apollo Client), and CI/CD pipeline setup.
London, England, United Kingdom (London, United Kingdom)
Co-Founder & CTO @ BabelBond | AWS Certified Solutions Architect | Ex-Head of Tech @ Reckon Digital
Certified AWS Solutions Architect and CTO with 10+ years of hands-on experience designing cloud backends and microservices platforms. As Head of Technology at Reckon Digital, responsible for designing and deploying production systems on AWS for the UN (World Food Programme) and international enterprises (Baker Hughes). Specializes in serverless and containerized services on AWS (Lambda, ECS, CDK, CloudFormation), highly reliable relational databases (RDS Aurora), and data security.
Stockholm, Sweden (Stockholm, Sweden · On-site)
Member of Technical Staff @ Lovable | Software Engineer
Lovable core team engineer (Member of Technical Staff at Lovable). Specializes in systems software development, computer networking, Linux administration, TypeScript, and the architecture of the Lovable platform for rapidly generating and launching full-featured web applications.
London, United Kingdom (London, United Kingdom · On-site / Remote)
Senior Front End / Full Stack Developer contractor with Next.js, React.js, TypeScript, PostgreSQL & Supabase
Senior full-stack contractor in London with deep commercial experience building high-load frontends and backends on React, Next.js (App Router, React Server Components, Server Actions), TypeScript, and Supabase. At EdenMarsh independently delivered a turnkey MVP web platform for a well-known marketing agency with a PostgreSQL database on Supabase, analytics dashboards, and Vercel deployment. At uXentrik Ltd develops the OpenBody 3D platform on Next.js, Three.js, and Supabase Postgres DB.
London, England, United Kingdom (London, United Kingdom)
Senior Software Engineer at On | Full-Stack & Backend Systems Architecture
Senior Full-Stack engineer and consultant with 8+ years of commercial experience designing and scaling high-load digital platforms. Lead engineer at Swiss-British sports brand On, responsible for designing and scaling the customer profile platform. Deep expertise in TypeScript, React, and Node.js microservice architecture, technical interviewing, and adopting AI tooling in development.
London, England, United Kingdom (London, United Kingdom)
Senior Shopify Developer | Frontend Engineer | Liquid · React · JavaScript · TypeScript | DTC E-commerce Specialist | London
Senior Shopify Plus and Frontend engineer in London with 7+ years of commercial experience in DTC e-commerce. As lead developer at Komar (USA), independently owned the architecture and codebase of 9 profitable Shopify Plus stores for well-known brands (CuddlDuds, Le Mystère, Bedhead PJs, and others). Specializes in custom Liquid theme development, product page (PDP) conversion optimization, Core Web Vitals load-speed improvements, A/B testing, and third-party service integrations (Klaviyo, Make/n8n automations).
Geelong, Victoria, Australia (Geelong, Australia · Remote)
Lead Shopify Developer | Shopify Plus, Custom Apps & Subscriptions | 6+ Years Building Bespoke E-Commerce at Agency Level
Lead developer at the Haydon Power agency (Shopify Experts). Owns architecture and delivery of complex bespoke stores for international merchants. Works across the full platform stack: custom Liquid themes, admin and checkout extensions (Shopify Checkout & Admin Extensions), Shopify Functions, Node.js backend, and embedded custom apps. Previously spent about 4 years building storefront solutions at German e-commerce company Tante-E.
Boston, Massachusetts, United States (Boston, Massachusetts, United States)
Software Engineer at Stripe | Full Stack Web Developer
Software engineer at Stripe. Builds reliable full-stack solutions focused on user experience and critical payment-infrastructure stability. Also does independent web development for businesses, applying modern tech standards, transaction security, and automation.
London, United Kingdom (London Area, United Kingdom · Remote / Hybrid)
Senior React Native & Full-Stack Engineer | Supabase, Next.js, PostgreSQL | AI Pipelines & TypeScript
Senior full-stack engineer with 6 years of commercial experience who launched 20+ production systems for 600K+ users. Specializes in building web and mobile systems on Next.js, React Native, and Supabase (PostgreSQL, pgvector, realtime sync, Row Level Security). Designed the LeftOverChef platform with a monorepo architecture, RAG pipelines, and a Supabase backend. Built offline-first Argonaut and Auro apps with reliable data sync via Supabase workflows.
Buenos Aires / Remote (international Vercel team)
Forward-Deployed Engineer at Vercel | GitHub Star | v0 Ambassador | Next.js & Tailwind Specialist
Lead engineer at Vercel (Forward Deployed Engineer and Solutions Architect). Official v0 ambassador (Vercel's generative AI tool for building UI with Tailwind CSS and Shadcn UI) and GitHub Star recipient. 5+ years at Vercel advising global enterprise clients on frontend-architecture optimization, Next.js rendering, and scaling Tailwind CSS styles. Contributed to the Next.js Commerce reference repositories.
London, United Kingdom (London Area, United Kingdom)
Senior Full Stack Engineer at Marcura | PostgreSQL & Python/Node.js Specialist
Senior Software Engineer with extensive experience optimizing and scaling relational databases under high loads. At Marcura and ARTERA, responsible for designing data-storage structures in PostgreSQL and MySQL, removing query bottlenecks, configuring connection pools, and scaling cloud database instances on AWS RDS.
Founder betterwrite.io | Frontend Developer | Modder | Writer
Frontend developer and founder of betterwrite.io, an AI writing assistant product. Combines product-building experience with strong technical writing, from UI implementation to shipping features end-to-end.
Khmelnytskyi, Ukraine
Frontend Developer | React, Next.js, TypeScript | SSR, CMS & Shopify
Frontend developer specializing in server-side rendered React and Next.js applications, headless CMS integrations and custom Shopify storefronts for e-commerce clients.
London, United Kingdom (London, United Kingdom · Hybrid)
Software Engineer | Imperial College | Python & Rust at Evervault
Software engineer at Evervault — a leading service for payment-data protection, encryption, and confidential computing. Graduate of Imperial College London. Specializes in Rust, Python, and TypeScript for building fast, reliable, resilient card-encryption systems and transaction-routing APIs. Extensive experience architecting secure cloud services on AWS.
London / Croydon, England, United Kingdom (London, United Kingdom)
Frontend Developer | React | TypeScript | Tailwind CSS | Next.js
Frontend engineer specializing in the modern React.js, Next.js (App Router, Server Components), and Tailwind CSS stack. Author of open learning projects and interactive AI apps (Memory Palace, Christmas Photo, Frontend-30). Deep hands-on experience building responsive, accessible interfaces with the Tailwind ecosystem: Shadcn UI, Radix UI, and Framer Motion.
London, England, United Kingdom (London, United Kingdom)
Python · FastAPI · React · Supabase · PostgreSQL · Gemini API · Docker | AI / Full-Stack Engineer
Full-stack and AI engineer with a master's degree from Queen Mary University of London. Builds and launches production services from scratch: designed and released the pdfexy.com platform on FastAPI, React, Supabase (PostgreSQL), and Vercel. At Varua Transport built a scalable fleet-management system with a REST API, an LLM interface for natural-language queries, and real-time dashboards connected to Supabase.
London, United Kingdom (London, United Kingdom)
Software Engineer (AI & Full Stack) | React · Node.js · FastAPI · Python | LangChain · RAG · Agents | PyData London & LangChain London Speaker
Full-stack AI engineer with a master's degree in Computer Science (Machine Learning & AI specialization, GPA 4.0). Builds the full AI product stack: from React frontends and FastAPI/Node.js backends to RAG pipelines and production multi-agent systems. Worked as an engineer at DXC Technology and Alankrita, designing agent orchestration architecture, evaluation (evals) frameworks, and context engineering. Regular speaker at the PyData London and LangChain London communities on production AI agent reliability.
TypeScript has transformed web engineering by preventing entire categories of runtime bugs before code reaches production. However, inexperienced developers often treat TypeScript as an afterthought, littering codebases with `any` casts and fragile type assertions that defeat compile-time safety.
ProofDevs connects you directly with independent senior TypeScript architects who design strict generic types, implement runtime schema validation with Zod, and establish end-to-end type safety from database schemas to client UI components at transparent rates between $50 and $100 per hour.
| Evaluation Metric | General Staffing Agency | ProofDevs Independent Senior |
|---|---|---|
| Hourly Billing Rate | $140 – $240 / hr | $50 – $100 / hr |
| TypeScript Rigor | Loose types, frequent 'any' assertions | Strict compile checks, generic inference, zero 'any' |
| API Safety | Unvalidated JSON payloads with manual casting | End-to-end type validation with Zod / tRPC schemas |
| Direct Access | Account managers and ticket dispatchers | Direct technical collaboration with the engineer |
| Repository Ownership | Staged deliveries subject to agency terms | 100% private Git repo commits on day one |
Senior TypeScript engineers enforce strict compiler flags (`strict: true`, `noImplicitAny: true`, `exactOptionalPropertyTypes: true`) to prevent subtle runtime null/undefined bugs.
In large applications and monorepos (managed with Turborepo or Nx), specialists structure shared package types, ensuring domain models and API contracts are defined once and inherited across frontend and backend services without duplication.
They leverage advanced TypeScript features including conditional types, template literal types, and discriminated unions to enforce business rules directly at compile time.
TypeScript types evaporate at runtime. Senior engineers pair compile-time types with runtime validation libraries like Zod or Valibot, ensuring external API responses and form submissions conform strictly to expected shapes before executing business logic.
Architecture Rule: The 'any' Contagion Trap
Introducing 'any' casts silences the TypeScript compiler and propagates untyped values throughout the entire call stack. Senior TypeScript engineers enforce 'unknown' with type narrowing guards or Zod schemas, maintaining 100% type safety across the system.
Project timelines for standard commercial TypeScript engineering tasks.
Independent TypeScript architects charge between $50 and $100 per hour. You retain 100% intellectual property ownership of all Git repositories, package configurations, and deployment keys upon milestone approval.
Teams standardizing on TypeScript usually weigh tRPC, REST with Zod, GraphQL codegen, and hand-written SDK clients against team size, client count, and contract churn. tRPC gives end-to-end inference for a single TypeScript monorepo. REST with Zod suits public APIs with many outside consumers. GraphQL fits clients needing flexible queries, while plain SDKs work when one backend serves one frontend without extra tooling.
Contract breakage is the real cost driver, so measure API change frequency before choosing. Services with weekly breaking changes benefit from generated clients and CI type checks that fail builds on drift. Stable internal APIs do well with tRPC inference and Vitest contract tests. Maintenance cost grows with GraphQL resolvers and codegen pipelines, which pay off past three client platforms but burden small teams.
| Option | Type safety model | Ecosystem and upkeep | Pick it when |
|---|---|---|---|
| tRPC 10/11 | End-to-end inference, no codegen step | Tied to TS monorepo; upgrades move in lockstep | One team, web plus mobile from same repo |
| REST plus Zod | Runtime validation at the boundary | Framework-agnostic; schemas versioned by hand | Public APIs, webhooks, third parties |
| GraphQL plus codegen | Typed queries per operation | Codegen pipeline; resolver upkeep | Many clients, flexible data needs |
| Plain typed SDK | Hand-written fetch wrappers | Lowest tooling cost; drifts without tests | Single frontend, stable backend |
Many products still run large JavaScript codebases with allowJs sprawl, missing null checks, and untyped API boundaries. A senior engineer migrates incrementally: enable checkJs on hot modules first, add Zod schemas at network edges, then convert files to strict TypeScript folder by folder. Tests run throughout, so the application ships every week while types tighten underneath the same shared CI pipeline.
Phased rollout keeps compile errors from blocking releases because strict flags tighten file by file. Phase one, tsconfig strict baselines with tsc in CI non-blocking, takes 8 to 16 hours. Phase two, converting 50 to 150 core modules with Vitest coverage, takes 25 to 60 hours. Phase three, flipping noUncheckedIndexedAccess and exactOptionalPropertyTypes with error triage, takes 10 to 20 hours per batch.
Taking over a loosely typed codebase starts with measuring any-density, not rewriting. The client provides repository access, tsconfig files, CI logs showing type-check status, recent production incident reports, and the three most feared deploy areas. A senior engineer then runs tsc with strict flags in report mode, counts explicit any casts, audits Zod coverage at boundaries, and checks whether shared packages pin compatible versions.
Some TypeScript projects cost less to re-scaffold than to salvage, and calling that early saves budget. Red flags include thousands of any casts across generated and handwritten code, five conflicting tsconfigs with skipLibCheck hiding real errors, and dependencies pinned three years back. A scoped rebuild of the contract layer, 30 to 60 hours, beats endless patches. Most other codebases reach strict mode within 20 to 45 hours.
Audit rule: fix versus re-scaffold
Re-scaffold only when repair exceeds replacement: any casts in the thousands, conflicting strictness flags across packages, or dependencies years out of date. Otherwise book a 4-hour audit that returns any-density metrics and a ranked conversion plan with hour estimates.
Strong TypeScript candidates reason about narrowing: why a union stayed unhandled, how a generic inferred wrong, and where unknown plus a guard replaced an any. Junior signals include non-null assertions sprinkled to silence errors, enums for string unions, and fetch wrappers returning any. Ask for a recent strict-mode migration story and listen for error-count numbers dropping across builds, not syntax trivia.
A paid trial of 3 to 5 hours exposes type discipline fast. Give the candidate an untyped Express route file, a Zod-less form handler, and one failing tsc check in CI. Acceptance criteria: zero explicit any added, runtime validation at both boundaries, tsc clean locally and in CI, and a short note listing the next 10 files they would convert with hour estimates.
You will receive matches with available senior TypeScript engineers within 2 to 4 hours of submitting your requirements.
Rates range from $50 to $100 per hour, based on expertise in full stack type safety, monorepos, and runtime schema validation.
Yes. Our engineers execute phased migrations: establishing build pipelines, adding strict compiler configurations, and converting modules incrementally without downtime.
Yes. Our TypeScript specialists architect full stack solutions spanning React, Next.js, Node.js, Fastify, and ORM database layers.
You own 100% of all Git repositories, shared packages, and CI/CD pipelines upon milestone signoff.
Pick tRPC for a single TypeScript monorepo, REST with Zod for public APIs and webhooks, and GraphQL when three or more client platforms need flexible queries. A 2-hour contract review maps your change frequency and consumer count to the right model.
Most engagements land between 8 and 60 hours: Zod contract architecture takes 15 to 35 hours, Turborepo setup 15 to 30 hours, and JS-to-strict-TS migrations 25 to 60 hours. Matching takes 2 to 4 hours and every proposal lists fixed hours.
Yes, when the project compiles and dependencies still install. You provide repo access, tsconfig files, and CI type-check logs; a 4-hour audit measures any-density and returns a ranked conversion plan. Projects with thousands of any casts may re-scaffold the contract layer in 30 to 60 hours.
Run a paid 3 to 5 hour trial at $50-$100/hr: type an untyped route file, add Zod validation to a form handler, and clear one failing tsc check in CI. Pass bar is zero new any casts, validated boundaries, and a clean tsc run.
Repository access, tsconfig and build configs, API specs or sample payloads, database schemas, and 30 minutes with the tech owner. With that package the engineer opens the first typed pull request the same day matching completes, usually 2 to 4 hours after your request.
Every engagement includes a 2-week defect window with free fixes for regressions from delivered work. Most teams then keep 5 to 10 hours monthly at $50-$100/hr for strictness tightening, dependency upgrades, and type-check performance reviews.
Yes. Build tuning with project references, incremental flags, and Turborepo caching typically takes 8 to 18 hours and cuts CI type-check times by half or more on large repos. You get before-and-after timings in the final report.
