So you can write SQL queries[1] in fastn documents, create dynamic urls[2], get request data[3], or write backend in wasm[4].
The input to sql queries are passed using bind parameters[5], so it should not have SQL injection issue.
FifthTry.com is built using fastn. You can checkout source code if lets-update[6] to see some open source fastn code.
[1]: https://fastn.com/sql/
[2]: https://fastn.com/dynamic-urls/
[3]: https://fastn.com/request-data/
[4]: https://fastn.com/wasm/
[5]: https://github.com/fastn-stack/fastn/blob/b639cdf59dd297f977...
[6]: https://github.com/fifthtry-community/lets-update
