[fragmede]

The error response telling me to upgrade to a paid plan isn't in json.

Also, I broke something, maybe in the caching logic. I tried 99999999 then 999999 then 99999 and down, and now I'm currently getting.

    ~$ curl https://api.isfizzbuzz.xyz/api/9
    Invalid number. Please upgrade to a paid plan to use imaginary, non-real, or non-numeric numbers.

also fails on 8.

[bliteral]

Whoops, fixed and fixed! And regression tests added.

I had made a silly, silly mistake when I went to restrict numbers longer than 7 digits from the "free plan", I had at the same time disallowed digits larger than 7 as being "valid digits", so anything with an 8 or a 9 had been "invalid".