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Parchment devlogPart 1 of 5

Why I'm building my own maps app

In this series

  1. 1Why I'm building my own maps appYou are hereI've spent most of my spare time since 2023 building Parchment, a maps app for people who walk, bike and take transit. Here's why I started it and what I want it to become.
  2. 2How Parchment started on free public APIsThe first version of Parchment was a Vue app wired up to free, open source map services. That worked well for a while, until rate limits, mismatched data formats and outages started getting in the way.
  3. 3Making map providers swappableParchment's code used to reference every map service by name, which made changing anything painful. I borrowed the way Home Assistant handles devices, and now switching providers doesn't mean rewriting features.
  4. 4How Barrelman spun out of ParchmentThe APIs I depended on couldn't do a lot of what I wanted, so I started building my own backend for search, routing and map tiles. It ended up becoming a separate product with its own business model.
  5. 5Where Parchment is todayParchment is in closed alpha with a small group of testers. Here's what's working so far, and what I want to finish before opening up a beta.

I started Parchment in November 2023 and it’s eaten most of my spare time since.

OpenStreetMap is the biggest open map of the world. Volunteers have traced and tagged it down to the bench outside the pub and the step at the front door. The data is incredible, and I wanted a maps app that actually makes use of it.

Parchment's globe view. The map is all OpenStreetMap data, drawn with open source renderers.

What it’s for#

Most mainstream maps apps are driving apps with a transit tab added on. I understand why from a business point of view, but it makes for a pretty frustrating experience if you don’t own a car.

I ride a bike and take the train, so I built Parchment around cycling, transit and walking instead of treating them as an afterthought.

In practice that mostly means mixed trips. A lot of my trips are a walk to a bike rack, a ride to the station, a train, and a walk at the other end, and I want to plan that as one trip. It also means showing the details you only care about when you’re actually outside: hills, unpaved surfaces, a curb you have to lift a wheel over, which station entrance has no stairs, and whether the bus stop has a shelter or is just a sign in the grass. Volunteers recorded a lot of that years ago, and almost no consumer app shows it.

Principles#

Open data. Parchment uses OpenStreetMap, so nobody can take the map away or start charging for it. When something is wrong, you can fix it at the source and everyone gets the fix.

Self-hostable. If I’m going to promise privacy, I think the best way to back that up is to let you keep your data on hardware you own.

You’re not the product. No ads, and no selling where you go. Companies can buy geospatial API access from Barrelman, and there’s a hosted option for people who don’t want to run a server at home, but your data is never what’s being sold.

It should be good. I want Parchment to be good enough that people would pick it even if it weren’t open source.

I won’t sell it. A lot of the software I’ve loved eventually got acquired and went downhill under owners who didn’t use it. If Parchment were ever acquired, a new owner could undo everything above, so I want to set it up so that it can’t be sold at all.

The rest of the series covers the problems, and the occasional lightbulb moment, I’ve run into while building my silly little maps app.