Compare and switch
InboxSpec vs Mailosaur
A dated comparison of price, daily limits, waiting and custom domains, including where Mailosaur is better.
Checked on 24 October 2026
Every Mailosaur fact on this page comes from its public pricing page and documentation on that date, listed under 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 If something here is wrong or out of date, tell us at hello@inboxspec.com and we will correct it.
At a glance
| Topic | Mailosaur | InboxSpec |
|---|---|---|
| Price | Personal from $20/month and Core from $50/month, both shown billed annually. Enterprise is custom. A 14-day trial is offered on Personal. | Free $0 (500 messages/month), Starter $19 (10,000), Developer $49 (50,000), Team $129 (150,000). Monthly billing only. |
| Volume | Personal: from 15,000 inbound emails/month, based on a daily limit of 500. Core: from 75,000/month, based on a daily limit of 2,500. | A monthly allowance with no daily cap. Overage is optional on paid plans. |
| When the limit is reached | Further emails are rejected until the count resets at midnight UTC. A test waiting for that email sees a timeout. | A timeout is a normal result with status "timeout", a count of non-matching arrivals and a hint. A spent allowance is a separate quota_exceeded error. |
| People | Personal includes 1 user and supports up to 3. Core includes 5 seats. | 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. |
| Custom receiving domain | Enterprise plans only. | Shared domain on Free. Custom receiving domains on every paid plan: 1 on Starter, 3 on Developer, 10 on Team. |
| Waiting | The client libraries wait by repeating a search request. The REST API has no wait endpoint. The default timeout is 10 seconds, and by default only the last hour of mail is searched. | 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 | Extracted codes and links on the full message, read after the wait. | The wait response already contains ranked codes and links classified as verify, sign_in, reset_password, unsubscribe or other. |
| Capture outgoing mail | SMTP into an inbox on every plan. POP3 and IMAP need Core or Enterprise. | Capture SMTP with STARTTLS on port 587 on every plan, including Free. |
Where Mailosaur is the better choice
- It does more than receive email: email compatibility testing on every plan, accessibility testing on Core, and SMS testing and email previews as add-ons.
- Official client libraries in many languages, plus test-framework helpers. InboxSpec offers REST examples in seven languages, but its own packages are not yet public.
- Every address under an inbox's subdomain works without registering it first. InboxSpec requires you to register an inbox before mail is sent to it.
- Enterprise offers SSO with SAML2 and OIDC, SLAs and an account manager.
Where InboxSpec differs
- The wait happens on the server, over REST and MCP alike, so a test or agent does not run its own polling loop. There is no hidden time window.
- Hitting your allowance produces a quota error you can act on, not a timeout that looks like your application never sent the email.
- Custom receiving domains start on the $19 plan rather than Enterprise.
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 are public. The TypeScript SDK and CLI are reviewed release archives that are not yet on a public package registry.
Switching
The Mailosaur migration guide maps messages.get, search criteria, codes and links to InboxSpec's wait.
Sources
All pages read on 24 October 2026. InboxSpec figures come from the pricing page and the wait guide.
- Mailosaur pricing
- Mailosaur usage limits
- Mailosaur custom domains
- Mailosaur API reference
- Mailosaur Node.js client README
Mailosaur, MailSlurp, testmail.app and Mailtrap are trademarks of their owners. InboxSpec is not affiliated with them.