CURRENT MAILING ADDRESS API
Address-validation APIs tell you whether a string looks deliverable. OnceAsk solves a different problem: whether the person your user means has a current, permissioned destination you can safely use now.
Call the delivery resolver with a contact ID or person query. OnceAsk returns a structured status so your application knows whether it can proceed, needs clarification, or should request recipient confirmation.
Instead of falling back to an old CRM or contact-card address, your application can trigger a permission request and let the recipient confirm their current destination.
The same resolution contract is available through REST and MCP, so a conventional application and an AI assistant can share a consistent current-address workflow.
HOW IT WORKS
Start from the contact or person the user already knows rather than a raw postal address string.
Receive a deterministic status such as authorized, permission_required, address_update_required, ambiguous, or not_found.
Proceed with authorized fulfillment or route the recipient through confirmation before retrying.
BUILT FOR PEOPLE + AI
OnceAsk gives people one current address to maintain and gives compatible assistants a permissioned way to resolve or request the delivery information they need.
QUESTIONS
No. Postal validation checks formatting or deliverability of an address string. OnceAsk focuses on whether a known recipient has a current, permissioned delivery destination and what to do when they do not.
Yes. OnceAsk supports both REST APIs and a remote MCP server. The MCP surface is designed specifically for compatible AI-agent workflows.
No. The preferred agent-facing flow can issue an opaque short-lived delivery token and fulfill through supported providers without returning the recipient's raw street address to the model.
Build an address book that is still useful the next time you need it.
Create your OnceAsk