# InboxSpec vs MailSlurp

A dated comparison of inbound allowances, inbox-creation limits, waiting and custom domains, including where MailSlurp is better.

<a id="guide-content"></a>



**Checked on 24 October 2026**

Every MailSlurp fact on this page comes from its public pricing page and documentation on that date, listed under [Sources](https://www.inboxspec.com/docs/markdown/compare-mailslurp.md#sources). Prices and plans change, so check their current pages before deciding. If something here is wrong or out of date, tell us at [hello@inboxspec.com](mailto:hello@inboxspec.com) and we will correct it.

<a id="at-a-glance"></a>

## At a glance

| Topic | MailSlurp | InboxSpec |
| --- | --- | --- |
| Price | Free $0, Starter $19.99, Pro $49.99 and Growth $129.99 per month. Enterprise is custom. Annual billing is offered. | Free $0 (500 messages/month), Starter $19 (10,000), Developer $49 (50,000), Team $129 (150,000). Monthly billing only. |
| Inbound volume | Free 500, Starter 1,000, Pro 5,000 and Growth 5,000 received emails/month. Extra usage on Pro and Growth is billed separately; the pricing page does not publish the rate. | 500, 10,000, 50,000 and 150,000 messages/month. |
| Creating inboxes | Counted separately: 100, 250, 1,000 and 5,000 inbox creations/month. Free and Starter are fixed caps. | Not counted or charged. Create a fresh inbox for every test run. |
| Custom receiving domain | Pro: paid separately. Growth: 1 included, more billed separately. | Shared domain on Free. Custom receiving domains on every paid plan: 1 on Starter, 3 on Developer, 10 on Team. |
| People | 1 user on Free, Starter and Pro. 2 included on Growth. | No per-seat fees on any plan. Every plan has the same fair-use ceiling of 1,000 people per workspace. No per-inbox, per-request or MCP charge. |
| Waiting | Server-side wait endpoints that hold the request open and return message previews, not full messages. | POST /v1/messages/wait blocks on the server for up to 285 seconds per call (default 120). Waiting is not metered and not rate limited; concurrent-wait limits apply. |
| Codes and links | Separate calls after the wait: one to fetch the email, then code and link extraction endpoints. | The wait response already contains ranked codes and links classified as verify, sign\_in, reset\_password, unsubscribe or other. |
| Overage | Billed separately on Pro and Growth. | Optional on paid plans at $1 per 1,000 messages, off until an owner sets a monthly budget. Free never incurs overage. |

<a id="where-mailslurp-is-better"></a>

## Where MailSlurp is the better choice

-   It is a much broader product: sending to external addresses, SMS and phone numbers, device rendering, inbox placement tests, email warm-up and AI-based extraction.
-   Code extraction has more modes, including pattern, LLM and OCR options.
-   Official SDKs in many languages, and Enterprise options such as SAML, audit logs and regional hosting.

<a id="where-inboxspec-differs"></a>

## Where InboxSpec differs

-   One meter: received messages. Creating inboxes, API calls and waiting are not counted, so an isolated inbox per test costs nothing extra.
-   The wait response carries the codes and links, so one call replaces wait, fetch and extract.
-   A custom domain is included from Starter, and every overage rate is published.

Some limits apply to InboxSpec whichever tool you compare it with:

-   InboxSpec is new. Production opened in October 2026, so it has no long operating record.
-   It only receives and captures email. It does not send to real recipients, test SMS, render emails in real mail clients or offer annual billing.
-   It has no SSO, SOC 2 report or uptime SLA.
-   REST and hosted [MCP](https://www.inboxspec.com/docs/markdown/mcp.md) are public. The [TypeScript SDK and CLI](https://www.inboxspec.com/docs/markdown/installation.md) are reviewed release archives that are not yet on a public package registry.

<a id="sources"></a>

## Sources

All pages read on 24 October 2026. InboxSpec figures come from the [pricing page](https://www.inboxspec.com/pricing) and the [wait guide](https://www.inboxspec.com/docs/markdown/waits.md).

-   [MailSlurp pricing](https://app.mailslurp.com/pricing/)
-   [MailSlurp wait-for documentation](https://www.mailslurp.com/docs/wait-for/)

Mailosaur, MailSlurp, testmail.app and Mailtrap are trademarks of their owners. InboxSpec is not affiliated with them.