mdfb — madeleine de forest-brown · staff product engineer

NavAssist

marine navigation software for inshore + offshore racing · web + offline app · co-creator & builder

problem

A csv is the best way to represent data in a fast paced environment - said no one ever. Weather changes, often and continuously. For professional sailors being up to date with the newest information quickly and clearly is imperative. How do you communicate to the rest of the crew nav changes when they happen mid race? How do we brief the team the night before with the routing plan? How do we share updates during an offshore race with no internet connectivity?

approach

Expedition does the routing; NavAssist takes its csvs and meteograms and represents them in a clear, configurable way. For coastal and offshore races: the route mapped alongside the weather data you choose to plot, tidal vectors to show where the gates are, sail analysis showing which sails the route calls for and for how long, and a Windy overlay for the big picture. For inshore: meteograms for a location, models compared, concise and easy to share. The offline app, hosted on one device, shares across the boat network to any other device via QR code or url. Responsive to its core — built for 32 inch monitors and iPhones alike.

build

Same codebase ships two ways: a hosted app, and one signed, notarised double-clickable binary per platform that bundles Python, the built front end and its own database, for use in offshore or inshore racing.

stack

python · fastapi react · vite postgres · sqlite pyinstaller lightsail · route53 terraform

on the water2026 season

Madeleine on deck mid-race with a laptop, working on NavAssist — being built onboard, between watches — first-hand user testing

Laptop on deck showing NavAssist code, crew at the wheels behind — being built onboard, between watches — first-hand user testing

The navigator reading NavAssist on a tablet at the helm at sunset — in use by the boat navigator

The navigator on the aft deck with a tablet, offshore at dusk — in use by the boat navigator

onefifty

location-aware photo sharing · ios + android · personal project

↗ google play

problem

Most social networking applications were never actually about bringing people together. I wanted to create an app which allowed you to see what your family and friends were up to without feeling influenced to buy something new and with no pressure to reply/react immediately. Not purely a highlights reel or a shopping app — built so "what have you been up to lately" turns into, "wow I saw your peonies bloomed last week, what else are you growing?"

approach

You can only share photos with people in your contacts, no concept of "following" here. You choose who you share every moment with explicitly. Someone else comments on a photo you shared - only you can see it. Consume yours and others moments in a feed so there's no "unread message" waiting for you to reply.

build

Expo / React Native client with Mapbox. TypeScript Lambdas behind API Gateway, HTTP and WebSocket. Postgres 15 + PostGIS on RDS via Kysely, S3 and CloudFront for media, SQS fan-out-on-write for feeds, SMS OTP. Every resource in Terraform.

stack

typescript expo · react native postgres · postgis aws lambda · sqs terraform mapbox

Madeleine De Forest-Brown

NavAssist

problem

approach

build

stack

onefifty

problem

approach

build

stack

experience

stack

frontend

backend & data

ai & tooling

infrastructure