Aug 12, 2025 19:00:00

'Wplace,' which allows everyone to draw on a map, caused OpenFreeMap to receive 100,000 requests per second, but it managed to withstand it

OpenFreeMap , a commercially available mapping service provided by software engineer Zsolt Ero, allows users to create and self-host custom maps for free. Ero reported that OpenFreeMap was suddenly inundated with a massive number of requests—100,000 per second—and that the cause was a drawing service called Wplace , which became a hot topic on social media in August 2025.

OpenFreeMap survived 100,000 requests per second
https://blog.hyperknot.com/p/openfreemap-survived-100000-requests

OpenFreeMap is a map service that uses map data obtained from the OpenStreetMap project, which creates open geographic information. The public instance is completely free to use. Because it's developed as open source, users can self-host it or use the public instance. Ero covers its operating costs through donations from users .

On August 8, 2025, Ero received a report that some tiles in OpenFreeMap were not loading, so he checked the logs of his web server application, nginx . This suggested that there was an unprecedented amount of traffic, and when he logged into Cloudflare, he found that there had been 3 billion requests in just 24 hours.

OpenFreeMap is a free service, so users don't have to pay for it, but if they were to use another mapping service,

MapTiler , it would cost more than $6 million (approximately 890 million yen) per month, and if they were to use Mapbox , it would cost twice as much.

Traffic also spiked sharply in the last five minutes, with around 30 million requests during that time, or 100,000 requests per second, and Ero was surprised that only a few tiles disappeared despite receiving so many requests.

A look at Cloudflare's dashboard showed that 96% of requests were processed without issue, with only 3.6% of data being corrupted. 'So that means OpenFreeMap is pretty much handling 100,000 requests per second, right?' Ero said.

The reason for this sudden surge in requests to OpenFreeMap is the popularity of the drawing service 'Wplace,' which became a hot topic on social media in early August. Wplace allows users to draw pixel art on maps around the world, and many users can draw on the same map in real time.

Wplace
https://wplace.live/

Wplace uses OpenFreeMap as its underlying map service. Wplace limits the number of pixels that can be written to 'one pixel every 30 seconds,' but some users appear to have been using 'scripts that can write a large number of pixels in a short period of time by opening and closing the browser.' This caused a sudden increase in requests to OpenFreeMap.

While Ero acknowledges that Wplace is an interesting project, he wishes he had been contacted in advance to ask if traffic was an issue or to donate operating costs. Because the burden on OpenFreeMap became too great, Ero had to temporarily stop requests from Wplace. Fortunately, Cloudflare sponsored OpenFreeMap's bandwidth in 2024, so Ero did not incur any financial burden.

Ero then got in touch with the developers of Wplace, who were unprepared for the sudden increase in traffic, as the number of users had grown to 2 million in just a few days. Ero offered to help them set up a self-hosted OpenFreeMap instance, which would be ideal for this use case.

Ero said he learned a few things from this incident: 'We should implement bandwidth limits based on the referrer ' and 'We need to improve our server settings to fix the empty tiles.'

Ero is also accepting donations to OpenFreeMap via GitHub.

Sponsor @hyperknot on GitHub Sponsors · GitHub
https://github.com/sponsors/hyperknot