gpx.studio, Rotorflight, Basis: three projects past $1,000 a month, and the donors, vendors and one departing sponsor behind them

Three open-source projects ran above a thousand a month through 2026, and all three got there the same way: sponsorship collected on a public ledger. What separates them is who sends the money and what it pays for once it lands. gpx.studio is paid by 1,442 of the people who use it, five euros at a time, and the money goes to servers. Rotorflight is paid by the two companies that sell the radios its firmware runs on, and the money goes to development radios and test parts. Basis was paid by one organisation that put its maintainer on $4,500 to $5,700 a month, and those payments stopped in May.

Every figure below comes from a collective page or a transaction ledger, read on September 24, 2026. Open Collective publishes what a project raised, what it disbursed and a dated record of both, so the receipts can be counted month by month. A collective holds project money, and each case says where it goes.

What it is: gpx.studio is a free online editor for GPX files, the route files that watches, bike computers and phones produce, with route planning, batch file processing and elevation profiles running in the browser. The repository is MIT-licensed with 1,218 stars and was first pushed in April 2024. 1

Public money figure: The collective's page puts the estimated annual budget at €16,706, about €1,392 a month, against €13,520.85 raised and €4,578.42 disbursed. 2 The ledger recorded between €1,566 and €1,940 in contributions in each month from April through September 2026, across 615 to 875 transactions a month. 3

Who pays: 1,442 contributors, nearly all of them individuals. The largest single gift on the page is €200; the recurring tiers are €5 a month and €5 a year, and the biggest monthly supporter gives €85. 2

The model: Sponsorship priced for people: a one-off donation from €1, a yearly supporter tier at €5 a year, and a monthly tier at €5 a month. 4

The trigger: The project moved its funding to Open Collective on April 2, 2026, after five years of collecting donations on Ko-fi, and placed the new collective under Open Source Europe. The same announcement swapped the map engine from Mapbox GL JS to MapLibre GL JS and the routing engine from BRouter to GraphHopper, two open-source replacements the collective could then pay for. Two later updates — new map styles and self-hosted tile infrastructure in May, and better elevation data in June — came out of the same fund. 567

What the money buys: Hosting. Every paid expense is a receipt submitted by admin vcoppe: €321.28 for the MapTiler unlimited plan covering June and July, €84.75 for a Cloudflare tile-hosting invoice, €24.19 a month for an OVH load balancer, €1,986.07 for a year of two OVH servers running the routing engines, €993.03 for a year of an OVH server serving OpenStreetMap points of interest, and €83.49 a month in support to GraphHopper. 8 Every line on that list is a bill, and the maintainers' names appear only as the people who submitted the receipts.

It works when ordinary people reach for your tool often enough to notice it is free and can thank you in the same currency twice. Three hundred of them at €5 is €1,500 a month, and six months of gpx.studio's ledger shows the shape of it: 615 to 875 entries a month, none of them large.

It fails when your users are organisations, who want a contract and a named support contact rather than a €5 tier. It also fails as income, because this money covers a hosting bill: a traffic spike or a price rise at a map provider puts the project back where it started.

What it is: Rotorflight is a flight-controller firmware suite for single-rotor RC helicopters, built on Betaflight 4.3. It covers the firmware, a configurator for flashing and tuning the controller, a blackbox log analyser, and radio scripts. The firmware repository is GPL-3.0 with 160 stars, and the project publishes across roughly eighteen repositories. 910

Public money figure: The collective estimates the annual budget at €16,993, about €1,416 a month, against €10,425.94 raised and €996.36 disbursed. 11 Monthly receipts ran between €1,140 and €2,413 from March 2026, after a first contribution of €179.12 in February. 12

Who pays: Two radio manufacturers, at €500 each per month. RadioMaster and Frsky RC have each given €3,500 since March 2026. Petri Mattila is the largest individual contributor at €2,000 since June 2026, and below him sit a second €500 account, €500 from JACK, and a tail of €20 to €100 donations. 11

The model: Sponsorship: a €5 monthly backer tier, a €100 monthly sponsor tier and an open donation box, with both manufacturers paying above the published sponsor tier. 13

The trigger: The vendors arrived in the same window as the releases. The collective opened in January 2025 and took in almost nothing for thirteen months; RadioMaster and Frsky RC began paying in March 2026, and the suite has shipped firmware, configurator and radio-script updates through September 2026. 10

What the money buys: Development radios and test hardware: a Rotorflight helicopter system and parts at €395.88, customs and processing fees on a RadioMaster TX16s development radio and ELRS sensors at about €160, an Avion speed controller at £42.48, and two AI coding subscriptions for maintainers at €107.10 and A$340. 14 Nine months of vendor money has left €996.36 spent against €10,425.94 raised, so most of it is still in the account.

It works when your software runs inside hardware that someone else sells. RadioMaster and FrSky ship radios whose owners fly helicopters running Rotorflight firmware, and €500 a month is a smaller bill for a manufacturer than maintaining a fork or watching those customers move to another radio.

It fails when no company's revenue passes through your code. Hobbyists gave €179 in the collective's first active month, before the vendors arrived, and both manufacturers pay one month at a time.

What it is: Basis is a set of libraries for building social VR applications in Unity, plus a demo framework that shows the parts working together. Its funding page describes it as MIT-licensed with no locked features; the repository shows 500 stars and was last pushed on September 19, 2026. 1516

Public money figure: The collective estimates the annual budget at $61,660, about $5,138 a month, against $57,296.70 raised and $53,612.13 disbursed, leaving $3,684.57 in the account. 16 Since June 2026 monthly receipts have run between $1,075 and $2,075. 17

Who pays: V-Sekai, an open-source virtual-reality organisation, gave $50,000 in $5,000 monthly instalments from August 2025 to May 2026, about three-quarters of everything the collective took in over that period. Receipts fell from $6,310 in May to $1,205 in June, the month the instalments stopped. What remains comes from individuals and small organisations: yewnyx at $2,350, Ryan at $1,775, SuperNekoya and Jinxxy at $1,400 each, Shane Harris and Merlin at $1,300 each, Matt Town at $1,085 and Charles Lohr at $950. 1618

The model: Sponsorship with a support tier on top. A $100-a-month sponsor slot offers priority support and direct communication, a $5-a-month membership sits below it, and the page carries a stated goal of $150,000 a year to support its lead developer. 19

The trigger: V-Sekai's first instalment arrived in August 2025, weeks after the collective opened, and the expense ledger shows what it turned into: nine monthly invoices from maintainer dooly for "Full-time development and maintenance", running $5,100 in September 2025, $4,500 in October, $5,250 in November and $4,649.16 in December, then $5,200 to $5,700 a month from January through May 2026. Between June and mid-August the expense column is empty, and the newest paid line is $1,000 to Spades on September 18, 2026, covering a work period from August 23 to September 18. 20

What the money buys: A maintainer's time, priced by the month for ten months and by the work period since. For most of the past year this figure was a salary rather than a bill, and the ledger's expense list shows it line by line.

It works when one organisation's own roadmap depends on your framework and it would rather pay you than fork you. V-Sekai's $50,000 bought ten months of full-time attention, which is the outcome most maintainers are asking for when they open a sponsorship page.

It fails when that organisation's plans change. A single payer carrying three-quarters of the budget is a job with one client, and the month the instalments stopped the income fell by four-fifths and the salary invoices ended. The $100 support tier underneath is a harder sale than a logo on a page. Find the companies whose products break without you before you build a budget on their continued interest.

Each annual figure is the collective's own estimate from recent activity, and it moves: Basis's still carries instalments that ended in May.

Start from the payer you already have — the people who use the tool, the vendors who ship it, the organisation whose roadmap leans on it — and price the recurring cost that payer is already absorbing. gpx.studio's donors cover servers. Rotorflight's vendors cover hardware. Basis's sponsor covered a person, and when it left, the person's invoices went with it.