iOS & Rails Developer — Fractional CTO
Jérémy Lagrue
15 years' experience, ex-CTO — Quebec
Fifteen years of software development — first on iOS, then on Ruby on Rails. Six years as CTO of Potloc: from building the platform to a 50-person engineering team, through to technical due diligence during funding rounds.
About
I've been designing and building Rails and iOS applications since 2008. I started during my engineering studies in France, running agencies with Marian Paul. We delivered over a hundred applications of all kinds, for individuals and large companies alike. Then I spent six years as CTO of Potloc. I've managed teams of 3 to 50 people, and it taught me to weigh delivery speed, technical debt and business goals against one another. That perspective is what I bring to every engagement, on top of the code.
Background
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Independent
I offer flexible support for early-stage startups (under 20 employees): building out an engineering team, architecture reviews, Rails/iOS development, or extra hands on a critical sprint. Available 15 hrs/week — a good fit for a recurring engagement or light, ongoing strategic support.
Projects
sortireer.com — see the case study below.
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Potloc
CTO & co-founder of Potloc
From 2013, sharing Wasappli's offices with Rodolphe and Louis, I followed Potloc's early development closely and advised them on technical matters. Three years later, I joined the team as CTO. Over six years I successively built the platform, formed the Software team, then set up the Product, Data and Compliance teams, supporting the company's growth from 3 to over 200 people — 50 of them on my teams.
- Hiring and leading the engineering teams
- Defining technology choices and architecture
- Data security and regulatory compliance
- Technical due diligence during funding rounds
- Shaping the product roadmap in line with strategic goals
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Wasappli
iOS & Rails Developer — CEO of Wasappli and iPuP
When the iOS SDK first launched, then an engineering student (École des Mines de Saint-Étienne, ISMIN program), I founded a development forum with classmates, then our first applications. With my partner Marian, we built an agency, published a reference book, then established our business in Montréal to support its growth.
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Co-authored the reference book “Programmez pour iPhone / iPad” (Eyrolles/Pearson, 2 editions, over 3,500 copies sold)
- Built a SaaS push-notification platform
- Technical contribution to the launch of the Verylastroom app
- Designed Getyourplace, a SaaS platform for student housing rentals
- Built an iOS app generator from ebook content
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Co-authored the reference book “Programmez pour iPhone / iPad” (Eyrolles/Pearson, 2 editions, over 3,500 copies sold)
What I do
Rails development
Ruby on Rails has been my craft since 2016 — first to build Potloc's platform from scratch, then to carry it all the way to a 50-developer team. I can spin up an MVP in a few weeks just as well as take over an existing codebase and bring order back to an architecture that's aged badly. I still write code every day, notably on my own projects.
- Designing and building web applications and APIs
- Taking over and stabilising existing projects
- Architecture choices and scaling
- Automation and third-party integrations
iOS development
iOS was my first craft — from the very first SDK, with my own agency (iPuP, up to 250 developers on our forum) and a co-authored reference book on the subject, over 3,500 copies sold. I designed and shipped several native apps between 2008 and 2016, in the Objective-C era. I'm getting back into the Swift ecosystem now — if you have an iOS project in mind, let's talk it through to see whether the timing works.
- Native iOS applications
- Maintenance and App Store updates
- Technical review of existing iOS projects
Technical consulting
An outside perspective, no fluff: I review your code or architecture, tell you where the real risks are — technical debt that will get expensive, choices that won't scale, fragile dependencies — and prioritise with you what's worth fixing now rather than in six months. Six years spent making these calls as a CTO, applied to your context over the course of an audit.
- Code audit and architecture review
- Technical decision support (build vs buy, stack choices, priorities)
- Preparing for technical due diligence
- Setting up a first engineering team
Engagements
For a founder or CTO who needs to make an important technical decision and wants input from someone who's been there. Architecture choices, build vs buy, setting up a first engineering team, reviewing a decision before it becomes expensive to undo. We talk, I ask the right questions, you leave with a clear direction.
Get in touch →For a team that needs senior reinforcement for a short stretch — levelling up a developer, structuring a technical initiative, or supporting a junior CTO through a decision that plays out over several days. Flexible format: pair programming, ongoing review, structured mentoring — to be defined together.
Get in touch →Case study
sortireer.com
The problem: moving a RREGOP/CRI pension from Quebec to France is a poorly documented administrative maze — everyone starts from scratch.
My role: designed, built and shipped solo, from idea to production — specs, development, hosting, content.
Stack: Ruby on Rails.
Result: a live platform, designed and shipped solo in a few days. No active promotion so far — the next step is getting it in front of the people who need it.
FAQ
Are you available for freelance work?
Yes, for one-off engagements or technical consulting. Write to me to discuss.
What are you working on right now?
I run sortireer.com, a service for former Quebec public-sector employees — my current technical playground and concrete proof of what I deliver (see the case study).
How does it start?
The simplest way: write to me directly and tell me where things stand. We set up a first 30-minute call, free and no strings attached, then move to one of the engagements above or a custom format depending on what you need.
Contact
jeremy.lagrue@hey.com — See my Malt profile →
The first conversation, 30 minutes, is free and no strings attached.