Selling stock quotes over an endpoint Google never documented
Sell NYSE price lookups for 720 satoshis a call.
The 402 layer is the same across this family of experiments. This one records a mistake that is easy to make and hard to see while making it.
The route forwards a symbol to google.com/finance/info?q=NSE:<symbol>, an
endpoint Google never documented, never supported and never promised anyone. It
was found by watching what a page requested, and for a while it worked well and
cost nothing, which is exactly why people build on things like it.
Then Google removed it. No deprecation notice, because there was no contract to deprecate. The service selling access stopped working, and its paying callers had no notice either.
The general shape is worth naming: an undocumented endpoint is a dependency with no version, no contract and no notice period. Fine for a script you run yourself, not fine underneath something other people pay for, because you have made a promise upstream of a promise nobody made you. The cheap insurance is a thin adapter written on day one, when it costs an hour.
The symbol also goes into the query unvalidated, the same issue as the link-safety endpoint.
The NASDAQ version is this file with the exchange prefix changed.