At the recent Small Business Web Summit, several member-company representatives hashed out a list of guidelines that may one day become a "Good Housekeeping"-esque seal for The Small Business Web, a consortium of API providers that are working together to create better small business tools. Among the list is an entire section devoted to APIs, where the seal would signify a series of promises to partners.
The summit Wiki has notes about the seal:
Our APIs won't suck:
The terms of access to any and all API will be articulated by clear and open qualification criteria
Our APIs will have a clear backward and forward compatibility policy
Our APIs will have published, versioned documentation with developer notifications
Our APIs won't required passwords for interoperability
Where available, Partners will be provided with advance access to API changes.
At this point, the seal is merely a proposal. The Small Business Web already has a manifesto, which requires signing companies to have an API and not be a jerk, among other requirements.
The requirements of the proposed seal are good practices for any API provider. Perhaps an even wider seal for use outside of The Small Business Web would be useful to make developers and other integrators feel comfortable using a particular API.
What promises would you want from a "trust seal?"