Your software is not working if all the third party services that depend on the API you provide are broken because you changed your API, or because your documentation is wrong.
You can work without documentation or without stable implementations if you control all the endpoints and ensure they always have the latest version (like mobile apps, web apps, etc). But if you can’t, you have to remember that every API version you’ll ever provide will have software using it, and you won’t be able to EOL the support for that version.
You can work without documentation or without stable implementations if you control all the endpoints and ensure they always have the latest version (like mobile apps, web apps, etc). But if you can’t, you have to remember that every API version you’ll ever provide will have software using it, and you won’t be able to EOL the support for that version.