Couryo protects every customer's reputation without catching anyone by surprise. Limits are public, show in the dashboard and in the API (in error messages), and every pause comes with a reason and numbers.

Trust levels#

Level	How you get there	Limit
0, sandbox	account created	25 per day, only to the account's own addresses
1, new	a verified domain (DKIM, return path and DMARC)	100 per day and 3,000 per month
2, verified	7 clean days and a checked company ID (CNPJ) or a payment method on file	1,000 per day, doubling every clean week up to 10,000
3, trusted	30 clean days on level 2 and a paid plan	your plan's volume, with the spending limit

You move up on your own. No manual approval, no form.
The dashboard shows what is missing, for example: "4 more clean days to reach level 2".
"Clean days" are days without a bounce or complaint pause.
Limits count recipients (to + cc + bcc), not calls. The day rolls over at midnight in the account's time zone; the month is the billing period or, on Free, the calendar month.
ck_test_ keys never count toward sending limits.

The limit at any moment is the lower of the level's and the plan's: on the Free plan, the cap is 100 per day even on level 2.

Plan limits#

Plan	Emails per month	Per day	Domains	Logs
Free	3,000	up to 100	1	7 days
Pro	50,000 included, overage per 1,000	the level's	up to 10	30 days
Scale	200,000 included, overage per 1,000	the level's	up to 50	90 days
Enterprise	custom	custom	unlimited	extended

Domains count across all projects of the account. Above the limit, the API answers 403 domain_limit_reached; deleting a domain frees the slot.
On Free, sending stops at the monthly quota (monthly_limit_reached) and resumes next month, with no charge.
On paid plans, overage is billed per started block of 1,000 emails. See pricing.

Spending limit#

Under Billing, you set how much overage you accept per month. When overage reaches that amount, all sending stops (transactional and marketing) with spend_limit_reached, until you raise the limit or the period renews. Nothing is charged above the cap.

Limits that pause#

Metric	Pauses when
Bounce rate	above 3% over the last 24 hours, with at least 50 sent
Complaint rate (marked as spam)	above 0.05% over the last 7 days, with at least 200 sent and 2 complaints

Rates are per account, measured in real time, and sit well below what major providers tolerate, so problems get fixed early. Policy blocks from the receiving side (5.7.x) do not count toward the bounce rate.

Pauses#

When a rate goes over the limit, the pause is gradual:

marketing email stops;
critical transactional email (password, login, billing) keeps going, with up to 30 per day;
you get an email with the reason, the numbers and what to fix.

Above a 10% bounce rate or a 0.5% complaint rate, the pause is full, including at the sending engine, and only a person on the team can lift it. A full stop also happens on clear fraud, such as phishing or a purchased list.

While paused, the API answers sending_paused with the reason, the numbers and how to fix it, and the dashboard shows the same, with a Request review button.

Request a review#

Disagree with a pause, or already fixed it? Use the Request review button in the dashboard and explain your case.

Right away: an AI agent reviews the request against your account data and decides clear cases. If approved, the account spends 48 hours under observation (status limited), with up to 50 per day, and returns to normal if the rates stay healthy.
Within 1 business day: if there is still doubt, a person on the team reviews it and replies with the reason.

The full rules are in the acceptable use and suspension policy.

Rate limits#

Each key has a 1-second window (10 calls per second by default). Every response carries these headers:

Header	What it says
`RateLimit-Limit`	how many calls fit in the window
`RateLimit-Remaining`	how many are left
`RateLimit-Reset`	seconds until the window restarts
`Retry-After`	on `429 rate_limited`, how many seconds to wait

On a 429, wait for Retry-After and retry with the same Idempotency-Key. To send many emails at once, use a batch: up to 100 per call.

Sizes#

What	Limit
Recipients per email (`to` + `cc` + `bcc`)	50
Emails per batch	100
Attachments per email	20
Request body (with Base64 attachments)	30 MB
`html` or `text`	5 MB each
Scheduling (`scheduled_at`)	up to 30 days ahead

Limits and trust levels