Where you start
- An idea or a specification
- Mock-ups or a Figma file
- A prototype built with an AI tool
- An MVP with its first users
- An application already in development
Take your web app from prototype to product
I'm a senior full-stack developer who turns an idea, a prototype or an MVP into a web app that holds up in production, fully remote. You work with a one-person product team, from scoping to the updates after launch.
Jean-Baptiste Thery
Senior full-stack TypeScript & AI freelance developer
Agentic developer, within your rules
Available for fully remote freelance
- Project
- Web app, SaaS or MVP, with iOS and Android apps if needed
- Pricing
- Fixed price, or day rate of €550 excl. VAT (indicative)
- Delivery
- Fully remote, with agreed review milestones
001
001·The service
What a prototype needs to become a product
A prototype, even one built with Lovable, Bolt or v0, shows what the product could be. Production asks for more, so I keep what works and rebuild what would not hold up.
I handle the whole chain, from architecture to release, and document each decision for whoever maintains the product next.
What the engagement covers
- A written scope: the first release, what to keep from your prototype and the target architecture
- Accounts, payments, data storage and the integrations your product depends on
- The web app, plus iOS and Android apps when the product needs them
- Accessibility, performance and language requirements set during scoping
- Automated tests, a CI/CD pipeline and monitoring for repeatable releases
- Documentation and a handover, or maintenance after launch
From your starting point to production
What production adds
- Accounts and permissions
- Payments and subscriptions
- Data and backups
- Security
- Accessibility
- Several languages
- iOS and Android apps
- Monitoring and support
002
002·How it works
From your first message to the handover
The same four steps on every engagement, so you know what happens next and what you receive.
You describe your project
Send a short brief on Malt or LinkedIn: your project, budget and target date. I confirm availability and the next step.
We agree the scope
Scope, schedule, pricing (fixed price or day rate), working hours and how we communicate, agreed in writing before work starts.
You follow the work
Code reviews, demos or written reports keep progress visible. Every change I deliver is reviewed and tested.
Handover and follow-up
Documentation, recommendations and, for development work, code whose rights the contract assigns to you. Maintenance by agreement.
003
003·Projects
Applications I built or rebuilt
WorkoutGen, which I co-founded, then a new frontend, a complete rewrite and a full modernisation for three clients.
Personalised workout generator, web and mobile
Programs built from each member's profile, for more than 51,000 members in October 2026 (workoutgen.app). I built the app end to end as co-founder and sole technical owner.
Sciences Po's thematic mapping tool
Print-quality maps from up to millions of rows, computed in the browser, even offline, with no data sent to a server. A complete rewrite designed by the Cartography Lab, which I developed.
B2B prospecting platform, web and mobile
Sales teams discover leads on the web, iOS and Android from one React codebase, which I built from scratch and owned for 21 months.
004
004·Recommendations
What clients and colleagues say
“I strongly recommend working with JB. He was instrumental in getting our frontend off the ground, handling everything with zeal, unwavering dedication, and unparalleled reliability.”
LinkedIn“Jean-Baptiste a été très réactif et très organisé. Je recommande à 100% ses services.”
Malt“Jean-Baptiste nous a aidé dans le développement frontend de notre outil Sweez. C'est un développeur talentueux et hautement compétent. Son expertise technique et sa capacité à résoudre les problèmes de manière créative font de lui un atout précieux pour toute équipe de développement. Il est fiable, consciencieux et démontre une grande attention aux détails dans son travail. Il communique bien et est force de proposition. La qualité de son code et sa capacité d'adaptation sont remarquables.”Malt005
005·About
One developer for the whole product
I was already shipping to production for clients such as Oney, Biodiv-Wind and Suzuki France. That was before AI coding tools; the code I now write with coding agents, within each client's rules, meets the same standards of testing and review.
Through jCode, I work with public institutions, established companies and startups. My own products, WorkoutGen and Ragmir, taught me what follows a release.
- of web development
- 10 years
- missions completed on Malt (November 2026)
- 80+
- as a freelancer
- 7 years
- from 47 client ratings on Malt (November 2026)
- 5.0/5
Areas of expertise
006
006·Explore more
Related services and products
Audit and recoveryImprove an existing applicationAI featuresAdd AI, agents or automation to your productProductsProducts by jCode
Compare the available services on the services overview.
007
007·FAQ
Planning your product
Can you start from a prototype or an application already in development?
Yes. I first review the code, the deployment and what production still needs, then propose what to keep and what to rebuild. Application audit and recovery covers that first step.
How long does a first version take?
It depends on the features, the integrations and what already exists: scoping sets a first release and its estimate. AI coding tools do not remove the tests, security and releases a product needs; the agentic development page sets out how I use them.
Do you work at a fixed price or on a day rate?
Both. A fixed price suits a clearly defined scope; a day rate, indicative €550 excluding VAT as of October 2026, suits a product whose needs will change.
Do you also build the iOS and Android apps?
Yes, when scoping shows your product needs them. WorkoutGen, which I built, is published on the App Store, Google Play and the Microsoft Store.
Who owns the code you deliver?
The contract provides for the assignment of rights to the code I deliver to you, including code written with the help of AI tools.
Can you maintain the product after launch?
Yes. Maintenance, support and further development can be part of the agreement, with their scope and availability agreed separately from the initial build.
008
008·Contact
Let's talk about your project.
Tell me what you want to build or improve, your budget and your target date.
- Fully remote
- English or French
- France · UK · US