The only bulletproof way is to change your business model to make these useless, irrelevant or no longer threatening. Yours and the user’s incentives should be

The only bulletproof way is to change your business model to make these useless, irrelevant or no longer threatening. Yours and the user’s incentives should be aligned. If you serve content, put it behind a paywall and rate-limit based on the maximum amount a human can reasonably consume and stop caring whether the user uses your own client or something like this - after all you’re getting paid either way. The only businesses that are threatened by unofficial API clients are cancerous “growth and engagement” crap where the “value” is the wasting of the user’s time. Don’t be such a business and you’ll be fine.