So to add to this message above, there already is a great JavsScript client SDK-library, made by @Gregory Goijaerts Goijaerts* called bunqJSClient (available on GitHub), I would like for bunq to fork this and built upon it to expand it into a full SDK and QuickStart. (As Gregory is currently not actively developing either project.)
But like me, a lot of others depend on an up-to-date and interoperable version of bunqJSClient with the current version of the bunq API, both in the sandbox and in production, to run their own projects and integrations.
Due to personal decisions, Gregory and the other devs in that repo, as far as I know, are not planning to give either github repository any time or attention it desperately needs (due to breaking changes in the bunq API), so I would like to call on all other freelance devs out there who use bunq and all those brilliant devs of bunq to take over from them.
*(also the creator of bunqDesktop-application)