Can I use the Trackmania.io API?

Yes, you are allowed to use the Trackmania.io private API, as long as you understand and follow the following disclaimers:

Consider whether you can and want to use Nadeo's own API. This reduces stress on Nadeo & Openplanet servers.
The API is unsupported. If I remove/change something, I will (likely) not give notice of it, and you'll have to deal with it yourself.
The API is undocumented. You're on your own to figure out how the API works and what you need from it.
Use a proper user agent header that describes your project or purpose so that I can see who and what is using the API. If you pretend to be a browser, you will be blocked.
There is a rate limit of 40 requests per minute (this might still change). Please be respectful of my server resources as well as Nadeo's. Cache stuff! Please let me know if you're planning to do any kind of "bulk" requests!
If you need more requests per minute, please contact me to request an API key to raise the limit to 150 requests per minute.
I have the right to block anyone from using the API if I deem their usage a nuisance. To request an unblock, please contact me.
Let me know what you're working on! I'm always curious and it lets me understand how people are using the API and who to contact about certain things if any contact is needed.

Banned API usage

There's a couple things I do not allow the API to be used for.

Do not use the API for a "find someone's rank in the leaderboard" app - this creates a lot of requests, and is exactly what the Club Edition of the game is for!
Anything else which purpose is to work around restrictions in Starter or Standard editions.
24/7 monitoring at a very fast rate - this is still allowed, but at a slower rate of at most 1 request per minute.

If you're still unsure about your use of the API, feel free to DM @miss on Discord or @codecatt on Twitter with any further questions.