A **platform** is a product that mints [temporary inboxes](/ai-agents/temporary-inboxes) for its *own* users, through the SendOps API, and hands each user a link to read their mail without a SendOps account. This page covers what the platform's SendOps workspace needs. The integration itself, with every request and response, is in the [developer guide](https://developers.sendops.dev/api-reference/inboxes-for-platforms).

## The workspace behind the key

A platform mints with an **API key from its own SendOps workspace**. That workspace is the one whose plan, settings and allowances apply to every inbox the platform mints, whoever the inbox is for. The platform's users never need a SendOps workspace of their own.

This is true however the platform is run. A self-hosted product, a self-hosted Markbase for example, is configured with an API key from a SendOps workspace that whoever runs it owns, and that workspace must be on a plan that includes what the product uses.

## Which plan you need

[Platform mode](/ai-agents/platform-mode), the workspace setting that applies caps per `account_ref` and accepts your users' sender addresses on your word, is **included from Business**.

| | Free | Team | Business |
|---|---|---|---|
| Temporary inboxes | — | ✓ | ✓ |
| Platform mode | — | — | ✓ |
| Inbox mints per period | — | 3,000 | 30,000 |
| Live inboxes | — | 25 | 500 |

The period is the workspace's monthly usage period; see [Plan limits](/billing/plan-limits#how-periods-are-counted). On Business with monthly billing and [overage](/billing/business-overage) on, mints beyond 30,000 continue and cost $5 per 1,000. Live inboxes are a hard limit on every plan.


  The plan's mint allowance sits on top of the abuse controls described in [Quotas and caps](/ai-agents/temporary-inboxes#quotas-and-caps), such as the 2,000-a-day limit in Platform mode. Restricted inboxes skip the abuse controls but **do** count against the plan's mint allowance: the allowance is what the plan sells, not an abuse control.


A workspace created before the current plans keeps its original limits until it changes plan, including access to Platform mode. See [Existing workspaces](/billing/existing-workspaces).

## The plan refusals

When the workspace's plan does not allow something, the API answers **HTTP 402** with the code `plan_limit_exceeded`. The `limit_type` field says which limit it was. A platform meets three of them.

| `limit_type` | When | What to do |
|---|---|---|
| `inboxes` | Minting on a plan without temporary inboxes (Free). | Upgrade the workspace to Team or Business. |
| `platform_profile` | Turning Platform mode on, on a plan without it (Team). | Upgrade the workspace to Business. |
| `inbox_mints` | Minting after the period's mint allowance is used up. | Wait for the next period, upgrade, or on monthly Business turn overage on. |

The body also says which plan lifts the limit (`upgrade_tier`), whether turning on overage would (`overage_available`), and links to the workspace's billing page (`upgrade_url`). Pass the message on to whoever runs the platform: the platform's own users cannot fix any of these.

Reaching the **live inbox** limit is not a 402. It is the same `429` with the reason `cap_org` that an over-quota mint has always returned, because waiting for an inbox to expire clears it.

## If the workspace leaves Business

Platform mode belongs to Business. If the workspace moves to Team:

- New mints follow the **standard** rules straight away: caps per API key, not per `account_ref`, and sender addresses must be verified.
- After the 14-day grace period that follows a downgrade, SendOps switches the workspace's Platform mode setting off and tells its admins. See [Moving to a smaller plan](/billing/plan-limits#moving-to-a-smaller-plan).
- Inboxes that already exist keep their restrictions until they expire.

## Related pages

- [Platform mode](/ai-agents/platform-mode): the switch, who can turn it on, and what you agree to
- [Temporary inboxes](/ai-agents/temporary-inboxes): what an inbox is and how it is used
- [Temporary inboxes for platforms](https://developers.sendops.dev/api-reference/inboxes-for-platforms): the developer guide
- [Plan limits](/billing/plan-limits): every limit on every plan