Why email sending is limited

When you send mail from an @inboxy.net alias, you're working within a quota. Here's why we cap it — and how much you actually get.

The short version

inboxy is a receiver-first service. We give you disposable addresses to hand out, collect the mail, digest it, and occasionally reply. We're not a bulk-mailer or a marketing platform.

To keep it that way — and to protect the @inboxy.net domain's reputation so your legitimate messages get delivered — we cap how much any one account can send. A tight quota means if someone steals your API key, they can't turn it into a spam cannon overnight.

How much can you send?

Your plan includes a monthly mail_send_quota. The Early Adopter plan is capped at 20 sends per calendar month. Each outbound message to a single recipient debits one unit.

You can see how many you have left under Account → API keys or by calling account_get from an MCP client.

What counts toward the quota

• mail_send — sending a brand-new message from an @inboxy.net alias to any recipient (external or another inboxy user). One debit per recipient, so a mail-merge to three addresses costs three units.
• mail_invite — inviting a friend to inboxy. Has its own separate cap: 10 per rolling 30 days, independent of mail_send_quota.

What doesn't count

• mail_reply — replying to an inbound message. Free, with a 5/hour rate limit. Replies are locked to the original sender server-side so they can't be abused.
• mail_forward — forwarding a message to your verified personal email. Free and idempotent. Locked to your personal_email server-side.

In other words: answering mail costs nothing. Starting conversations does.

Legitimate use cases

Twenty sends a month covers most real-world use:

• Receipts and confirmations — you're receiving these, not sending them.
• Replying to newsletters and customer support — covered by mail_reply, free.
• One-off messages — "Hi, thanks for the recommendation" to a friend, or a message from a script that checks in once a month.
• Invites — capped separately at 10 friends per month.
• Password resets and sign-ups — inbound mail only; the recipient's system does the sending.

If your use case needs more sends, your plan will eventually include a way to buy extra quota. For now, the limit is per-month and rolls over if unused.

Why we can't disable this

Sending reputation is shared. Every message sent from @inboxy.net affects whether future legitimate mail from that domain reaches other inboxes. If we let accounts send unlimited mail, one compromised key could tank the domain's reputation for everyone.

The quota lives server-side, not client-side — a leaked API key or MCP grant can't just be re-scoped locally. It's one of the reasons we ask for three sign-in factors — your account's sending privileges matter to the whole domain.

Stuck?

If your legitimate use case is blocked by the quota, email support@inboxy.net and tell us what you're trying to do. We're open to feedback on the limits.