Launch HN: Alter (YC S25) – Access control for multi-user agents

Alter is a platform that provides access control for multi-user agents, acting as a proxy to manage downstream credentials and enforce fine-grained runtime policies. It was founded by Srikar and Kevar, who saw firsthand the challenges of building agents in regulated industries. The platform supports hundreds of providers and has reliability as its top priority, allowing developers to build custom agents with features like policy control, user attribution, and audit logs. Alter has a free tier up to 10,000 requests and a usage-based pricing plan beyond that.