Does Zyntra charge for creating inboxes?

No. Addresses are not created or counted. Plans limit the emails you receive each month and the API requests on Free.

Is Zyntra's MCP server as capable as MailSlurp's?

No, on purpose. MailSlurp's agents can draft and send replies. Zyntra's five tools read and delete test email only, which suits an agent you don't want writing to anyone.

Comparison

Zyntra vs MailSlurp

MailSlurp is a broad email and SMS platform: it creates inboxes through its API, sends as well as receives, rents phone numbers, and checks rendering and inbox placement. Zyntra only receives: any address works without being created, and you pay for incoming mail.

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Side by side

MailSlurp facts are from its own website, checked on October 16, 2026. Prices change; check the sources below before you decide.

ZyntraMailSlurp

Free plan$0: 150 emails/month, 500 API requests/month$0: 500 emails received/month, 100 inbox creations/month, 50 retained inboxes

Entry paid planStarter: $9/month billed yearly, $11 monthly; 10,000 emails/monthStarter: $19.99/month; 1,000 emails received/month, 250 inbox creations

Next planPro: $29/month billed yearly, $39 monthly; 50,000 emails/monthPro: $49.99/month; 5,000 emails received/month, 1,000 inbox creations, then usage billing

Getting an addressAny address works without being createdInboxes are created through the API or dashboard; creations count toward the plan

Mail kept1 day for addresses you never created; 7 / 30 / 90 days for inboxes created in the dashboard (Free / Starter / Pro)Not stated on the pricing page; storage limit per plan (200 MB on Free)

Sending emailNo, receive-onlyYes: in-account test sends on Free and Starter, 500 external sends on Pro

SMS and phone numbersNoPhone numbers on Pro and above

AI agentsHosted MCP server: 5 tools, read and delete onlyHosted MCP server with scoped agent keys; tools include waiting for email, drafts and replies

Rendering and placement testsNoDevice rendering, inbox placement and email audits

UsersMulti-user teams are not offered1 user up to Pro, 2 on Growth

Which one fits

Choose MailSlurp if

Your tests or agents need to send and reply, not just receive.
You test SMS codes as well as email.
You also want rendering previews and inbox placement checks.

Choose Zyntra if

You receive more mail than you send: Starter covers 10,000 emails a month for $9–11.
Each test should make up an address on the spot, without an API call to create an inbox.
An AI agent should be able to read test email and have no way to send.
People read test mail in a browser and keep it for up to 90 days.

Questions

Does Zyntra charge for creating inboxes?: No. Addresses are not created or counted. Plans limit the emails you receive each month and the API requests on Free.
Is Zyntra's MCP server as capable as MailSlurp's?: No, on purpose. MailSlurp's agents can draft and send replies. Zyntra's five tools read and delete test email only, which suits an agent you don't want writing to anyone.

Sources

Receive test email without creating inboxes

Free plan. Send to any address and read it back over the API.

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