Trust is the currency the API economy runs on, and it is earned slowly and broken quickly. It is also genuinely political, because the relationship is asymmetric: the consumer commits their architecture to you, and you retain the ability to change the terms.
The things that build it are unglamorous. Put pricing on a public page, in front of the signup, with real numbers. I have trusted providers more for that one act than for almost anything else, because hidden pricing signals that the terms depend on who is asking. Publish rate limits before someone hits one. Run an honest status page. Keep a real change log. Announce breaking changes early with a specific date and reach the affected consumers directly.
The things that destroy it are equally consistent. Quiet sunsets. Terms that change without notice. Rate limits cut retroactively. Building a first-party product that competes with the ecosystem you encouraged. And the classic pattern of extracting as much value from developers as possible and then withdrawing the thing they built on — which does not just cost you those developers, it teaches an entire market that your platform cannot be depended on.
A useful test before any decision that affects consumers: would you be comfortable posting the internal reasoning publicly? If not, you are probably about to spend trust you will not get back.
