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Thomas CosiallsTC

Thomas Cosialls

CTO Full-stack · SaaS & Apps · Architecture

€500/day
3 projects
Paris, FR
8-15 years

Average response time: 1 hour

Freelancer profile translated to English.
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About Thomas

Transform your Idea into a Profitable Product, without sacrificing architecture

Launching a product or structuring your startup's tech? I am the CTO who codes; the one who aligns business vision with execution, using AI as a real-time accelerator and auditor.

Background:co-founder & CTO of a startup scaled from 0 to 15 people (Singapore, 5 years), 5 SaaS / mobile apps built from scratch, and several years of full-stack and blockchain freelancing (The Smurfs™, Sanofi).

🧠Vision & Strategy
  • Design + Product + Code + Infra:from idea to production
  • Robust architecture from day 1:zero technical debt, sustainable technologies, anticipated scalability
  • Anti vibe-coding:AI accelerates, but architecture remains human-designed by someone who knows what they're doing
💻Fullstack Execution
  • Frontend & Mobile:Next.js, Expo / React Native, App Store & Google Play
  • Backend:Node.js, NestJS, PostgreSQL, MongoDB, Supabase
  • Integrations:Stripe, payments, third-party APIs
  • Blockchain & Web3:smart contracts, DeFi, tokens
  • Infra:AWS, Docker, VPS, CI/CD
🚀 Why me?

I've lived the founder's reality: hiring, pivoting, delivering under pressure, scaling. No over-engineering: I deliver a solid, fast, scalable product. AI makes me go 5x faster, with up-to-date docs and tests, and early flaw detection.

Availability:full-time or part-time, independently or integrated into your team.

📞 Contact me for an initial strategic discussion.
  • English

    Native or bilingual

  • French

    Native or bilingual

  • Spanish

    Native or bilingual

Remote only
Primarily works remotely

Experience

  • Metrix Finance
    Blockchain Engineer
    CONSULTING AND AUDITS
    June 2025 - Today (1 year and 2 months)
    Paris, France
    - Creation of smart contracts to automate liquidity position maintenance on UniswapV3, UniswapV4 Aerodrome, Raydium, Orca
    - Jupiter CPI for swaps
    - Development in Solidity (with Forge and Hardhat tools) and Rust (with Anchor framework)
    - Creation of tests and simulations on mainnet forks

    🌐https://metrix.finance
    Web3.js Smart Contract Rust Solidity Blockchain
  • Revolt Games
    Full-stack Developer | Web3 - Realtime - Gaming
    VIDEO GAMES AND ANIMATION
    August 2024 - January 2025 (5 months)
    Paris, France
    Development from scratch of a real-time multiplayer online mobile game on Telegram (Telegram Mini App) with on-chain rewards (Hedera blockchain):
    👉 backend with Supabase and Node.js (fastify framework)
    👉 front-end with React + Vite
    👉 use of the Telegram SDK for a native feel
    👉 UI/UX integration from provided Figma designs
    👉 creation and deployment of the game's token (SPY coin) on the Hedera blockchain

    🚀 100,000 players registered in 3 months / up to 500 players online
    🌐https://t.me/Spyclubgame_bot/game
    React.js Vite Telegram Supabase Realtime
  • Proof2work
    Founder and Full-stack Developer
    EDUCATION AND E-LEARNING
    August 2023 - Today (3 years)
    Paris, France
    Proof2work allows searching for all smart contracts deployed by a given Ethereum address. Available on Ethereum, Arbitrum, Polygon, and Optimism chains.
    🌐https://www.proof2work.com
    Web3 Supabase Next.js TailwindCSS Blockchain

Reviews

5.0

Out of 3 ratings

ÁlvaroÁ

Álvaro

ATTOMO Digital

Reviewed on 9/7/2023

The truth is that it has been very easy to work with Thomas. He has carried out the project in an agile and very professional manner.
JulienJ

Julien

Iron Velvet

Reviewed on 8/31/2022

Recommendations

EA
FU
FU
+1
Emaster Agency and 3 other people have recommended Thomas

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Education

  • Master's Degree in Computer Science & Telecommunications
    ENSEEIHT
    2014

Certifications

Skill set

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