Maxime Kirch / Montréal, QC
Work Scale Contact
React Native & Node/Express · freelance · remote missions

React Native
& Node/Express
engineer.

I build mobile apps and the backends behind them. I've worked on real-time chat at six-figure concurrency, scoring systems that have to be provably fair, and AI pipelines running in containers. Comfortable across the whole stack, not just the frontend.

WHO I WORK WITH
Startups, large companies & product teams
Engagements
Mobile & Webapps
Backend & real-time
AI pipeline design
Languages
FR · EN
$ whoami
Sports data nerd, coffee lover, Jack Russell owner and probably too invested in finding the perfect tiramisù.
WORK04 case studies
01
Role
Mobile engineer
Product
Live community platform
iOS · Android
Stack
React Native · TypeScript
WebSockets clients
Native modules
Load
100k+ simultaneous
chat users

The Residency

Worked as a mobile engineer on a live community app peaking at 100k+ concurrent chat users. Client side of a mass-scale real-time product.

Scope

Owned React Native features end to end, real-time chat surfaces, releases and regressions on both iOS & Android stores, working against a backend built for mass concurrency.

Mobile performance

Kept the app at 60 FPS while messages landed at event-peak rates: list virtualization, render budgets, memoized message trees and disciplined state updates on mid-tier devices.

Integrations

Contributed to the technical integration of the DAZN live-chat partnership and to Auth API validation at 1M+ concurrent users during stress tests.

02
Role
Architect & engineer
Platform
iOS · React Native / Expo
Stack
Express · Supabase (RLS)
PostgreSQL · HealthKit
Anthropic API
Model
Freemium — cosmetics
+ insight tiers

JackFit

A fitness app where a virtual pet, Uma, lives on your real health data.

Problem

Health data is passive: you close your rings but nothing more occures. The brief was to convert daily biometrics into a progression system people return to without being nagged.

Architecture

Express API in front of Supabase. XP is computed server-side from activity, sleep and consistency signals.

Economy

Deterministic scoring means a given week always yields the same XP which is cheat-resistant. Cosmetics and premium insights monetize without touching the reward curve.

03
Engagement
Ongoing freelance client
Field
Aviation fuel logistics
Orly · CDG
Stack
Expo · TypeScript
Zod · TanStack Query
React dashboards
PRODUCT
Aircharge

Synaxe

Field app for the crews refueling aircrafts at CDG and Orly (France). Built to keep going deliveries even when the airport network drops. 

Constraints

Fuel truck operators log flight assignments, meter readings and delivery data straight from the truck. Losing the connection can't mean losing the delivery record : that's the actual constraint the app is built around.

Reliability

Zod validates every payload before it's trusted. TanStack Query handles caching and retries, so the app keeps working offline and catches up once the connection comes back.

Supervision

Dispatchers see trucks, flights and deliveries live on a dashboard built from the same data model as the field app.

04
Status
TestFlight / preprod
engineering case study
Role
Architecture & build
Stack
Node.js · Redis
Python AI engine
Whisper · Gemini
PostgreSQL · MinIO/S3
Shape
Containerized
microservices

Relevo

Voice-to-report for construction sites: an architect talks, a structured site report comes out.

Split

A Node.js + Redis API gateway handles auth, job queueing and delivery; a separate Python service owns inference. Two runtimes, two scaling profiles, one contract between them.

Pipeline

Whisper transcribes noisy site audio, an extraction pass pulls typed fields out of free speech, and Gemini composes the report from that structure.

Data

PostgreSQL for structured records, MinIO/S3 for raw audio and generated artifacts. Every job is reprocessable from its source recording when a model or prompt changes.

At scaleProduction numbers
1M+
Concurrent users

Contributed to the DAZN live-chat partnership integration, and helped validate the Auth API under load tests simulating 1M+ concurrent sessions.

100k+
Simultaneous chat users

Shipped the React Native client for a live-chat product running at that load over WebSockets.

60 fps
Under message load

Held 60 FPS on React Native while messages arrived at mass-event rates on mid-tier devices.

Core stackDaily drivers
React Native
Expo · EAS · native modules · perf profiling
TypeScript
Strict end-to-end · Zod at the boundaries
Node.js
Fastify · Express · WebSockets
PostgreSQL
Schema design · RLS · query tuning
Redis
Pub/Sub fan-out · queues · caching
Supabase
RLS policies · service-role write paths
LLM integration
Anthropic · Whisper · Gemini · scoped, non-critical paths
Docker
Multi-service compose · deploy pipelines
Track recordWhere I’ve shipped
NowFreelance — Synaxe (Orly / CDG ground ops)Expo mobile apps + real-time React dashboards
Past yearsThe Residency — mobile engineerReact Native client for live chat at 100k+ simultaneous users; DAZN integration, 60 FPS under load
Own workJackFit · RelevoFull-stack product architecture, AI pipeline design
Also builtA Tiusella — guesthouse booking websiteNext.js · Headless WordPress · Stripe