Section 1 is the commercial allowance you buy, and it also appears on the pricing page. Sections 2 through 4 are technical limits that keep shared infrastructure stable. They are set far above normal use: a customer using the Service as intended will not encounter them. They are published here rather than advertised because they are engineering guardrails, and because you should be able to read them before you need them.
1. Plan allowances
| Free | Growth | Scale | Pro | Enterprise | |
|---|---|---|---|---|---|
| Emails / month | 5,000 | 50,000 | 250,000 | 1,000,000 | Contractual |
| Active contacts | 25,000 | 100,000 | 500,000 | 2,000,000 | Contractual |
| Business units | 1 | 3 | 10 | Unlimited | Unlimited |
| Seats | 1 | 3 | 10 | Unlimited | Unlimited |
| Platform AI assists / month | 50 | 250 | 1,000 | 5,000 | Contractual |
2. Storage and ingest
The storage quota covers everything your account holds: contacts, data extension rows, data extension schemas, templates, emails, landing pages, and uploaded assets.
| Free | Growth | Scale | Pro | Enterprise | |
|---|---|---|---|---|---|
| Total storage | 1 GB | 10 GB | 50 GB | 250 GB | Contractual |
| Records imported / day | 5,000 | 50,000 | 250,000 | 1,000,000 | Contractual |
| Data imported / day | 50 MB | 1 GB | 5 GB | 25 GB | Contractual |
| Records / import batch | 100,000 | 100,000 | 100,000 | 100,000 | 100,000 |
3. Per-record limits
These are the same on every plan, including Enterprise. They describe the shape of a record rather than how much you may store, and no legitimate use requires exceeding them.
| Limit | Value |
|---|---|
| Fields per data extension | 512 |
| Size of one data extension row | 256 KB |
| Size of one field value | 64 KB |
| Length of a subscriber key value | 320 characters |
| Data extensions per account | 1,000 |
| Size of one uploaded asset | 5 MB |
| Length of an object name | 128 characters |
4. API rate limits
API requests are rate limited per account. When you exceed a limit the API returns
429 with a Retry-After header, and the correct client
behaviour is to back off and retry rather than to keep hammering. Sustained
disregard of a 429 is itself a breach of the
Acceptable Use Policy.
Bulk ingest through the events API counts against the daily record and byte limits in section 2, in addition to the request rate limit.
5. What happens at a limit
Reading, exporting, deleting, and sending always keep working. Only writes that would push you further past a limit are refused. An account that cannot delete or export could never get back under a limit, so we never take those away.
Contact ceiling
On the free plan, reaching the ceiling stops new contacts being added. On paid plans we notify you at 80% and again at 100%, imports keep working, and a fourteen-day grace window opens. New contacts stop at 110% if the account is still over at the end of it.
Storage quota
At 100% of quota, writes that would add data are refused. Deleting data or upgrading restores writes immediately.
Daily ingest
Further imports are refused until the rolling window clears. Nothing already imported is affected.
Per-record limits
The individual write is rejected with an error naming the limit and the actual value. There is no grace period, because a record above these sizes is a bug or an abuse rather than a growing business.
Imports are checked before anything is written, so a file that would exceed a limit is refused as a whole with the overage stated, rather than being half-loaded and then stopped.
6. How we count
Active contacts
A contact counts when its status is active or held. Contacts that have unsubscribed, hard-bounced, or been deleted do not count against your allowance. You are never charged for people who left.
Contacts in a terminal state are retained for 90 days so that suppression still works and so you can see what happened, then purged. Suppression of an address survives the purge permanently, so a purged unsubscribe can never be re-mailed by accident.
Contacts are counted across your whole account, including every business unit in it. The same person present in two business units is two contacts, because that is two records.
Storage
Storage is measured as the logical size of your stored data plus a fixed per-record overhead for indexing. It is not a measurement of physical disk, which in a shared database cannot be fairly attributed to one customer. Your current usage is shown in the app, and that figure is the one we enforce against.
Emails
One email counts once per recipient at the moment a send launches, counted against the UTC month in which it launched.
7. Changes and exceptions
We may change these limits with thirty days' notice by email to account owners, except where a change is needed sooner to protect the stability or security of the Service. The "last updated" date above always reflects the current version.
Any of these limits can be raised for an individual account. Migrations, seasonal peaks, and unusual but legitimate data shapes are all normal reasons to ask, and we would much rather raise a limit than have you work around one. Write to support@sentientmail.com.