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An identity gives an AI agent its own communication surface: a mailbox, optionally a phone number and iMessage support, a publicly reachable internet address (via tunnel) for receiving incoming traffic, and access to contacts and a credential vault.

By default, each identity gets a mailbox on inkboxmail.com (for example, your-agent@inkboxmail.com). A custom email domain lets your identities send and receive email from a domain you own (for example, agent@yourcompany.com) instead. Paid plans include custom email domains, ready to use once you verify the domain.

A recipient is a unique E.164 phone number your agent is connected with over iMessage. On the shared Inkbox iMessage router, the person always texts first: they start the connection by texting "connect @your-agent", so your agent never messages anyone cold. (A dedicated iMessage number on the Startup $200 option is the exception — it can start conversations, and the recipient cap applies only to the shared router.) Recipients can reply STOP at any time to opt out. See the iMessage docs to learn how connections work.

Startup includes a dedicated iMessage number, and the price picks how it behaves. On $200/month the number can start conversations with new recipients. On $180/month recipients need to start the conversation — the number replies once someone has messaged it. Both options include up to 100,000 messages per month on the dedicated number, counted separately from the shared iMessage cap, and you can switch options from the Console at any time.

When an organization reaches a shared or dedicated iMessage cap, sends from that pool pause until the cap resets or the plan is upgraded. Incoming messages still arrive. If you need higher iMessage limits without upgrading tiers, talk to us.

You're billed at the overage rates above. To keep overage spending in check, you can set an optional monthly overage spend limit in the Console — once reached, outgoing messages and calls that would incur overage charges are paused until your next cycle. Usage within your included allowances is never blocked, and in-progress calls and inbound usage can take spend past the limit. If overage is a significant share of your bill, talk to us about a custom allowance.

Receiving keeps working — inbound mail is always accepted, and it still counts toward the inbox's usage. A send that would push the inbox above its cap is refused until space is freed (delete messages or threads) or the plan is upgraded; deleting frees the space immediately. An inbox's current usage and its cap are on the mailbox object in the API.

Yes. Every plan includes IMAP and SMTP access, so you can connect an inbox to a desktop or mobile mail app — you sign in with the full inbox address and an API key scoped to its identity. See the mail-app guide for connection settings. One limit to know about: signed or encrypted mail cannot be sent from a mail client while the "Sent via Inkbox" footer applies, because the footer cannot be added without invalidating the signature — send unsigned, or remove the footer on a paid plan.

No. Allowances reset at the start of each billing cycle.

No. Prices exclude applicable taxes.