GetCourier vs MailSlurp for AI agent email and test automation
GetCourier and MailSlurp both give software an email inbox it can read over an API. MailSlurp is a broad email and SMS testing and automation platform: inboxes, phone numbers, device previews, audits, inbox placement and AI agent tooling, sold as monthly plans. GetCourier is narrow: one unauthenticated POST https://getcourier.dev/alias returns an inbox, and its wait route returns the verification code or magic link already extracted. MailSlurp facts were read from mailslurp.com and its pricing page on 2026-11-03; anything not stated there is marked not documented.
At a glance
| GetCourier | MailSlurp | |
|---|---|---|
| What it is | Inboxes for AI agents: create over HTTP or MCP, receive a code, reply. | Email and SMS testing, email quality and automation platform. |
| Signup | None for the free path. | Account; plans have a 7-day trial that requires a card (pricing page). |
| Entry price | Free tier; then US$0.01 per 72-hour inbox (pricing). | Messaging APIs US$49 a month or US$529 a year; Email Quality US$79 a month; both together US$128 a month. |
| Included volume | Pay per inbox; 100 messages held per inbox. | Messaging APIs plan: 5,000 received and 500 sent a month, 1,000 inboxes a month, 1 GB storage. |
| Receive and codes | Yes; codes and links extracted; wait long-poll. | Yes; wait for matching messages and extract codes and links. |
| SMS and phone numbers | No. | Yes. |
| Device previews, audits, placement | No. | Yes (Email Quality plan). |
| MCP | Hosted at /mcp, connect by URL, no key on the free path. | Listed on its homepage under AI agents (API and MCP access). |
| Payment | Prepaid credits in USDC on Base or BTC; x402 pay-per-call. | Card (card required for trial); crypto: not documented on its pricing page. |
| Other access | HTTP and MCP. | API, SDKs, SMTP, IMAP, webhooks, connected Gmail and Outlook. |
GetCourier: an inbox and a code in two calls
curl -s -X POST https://getcourier.dev/alias
curl -s -H "Authorization: Bearer $READ_TOKEN" \
"https://getcourier.dev/v1/sandbox/inboxes/$ALIAS/wait?timeout=55"The first call returns an address and a read_token (shown once). The second long-polls until mail arrives and returns the newest message with codes and links already extracted. Full routes are in the docs; over MCP the same steps are create_inbox and wait_for_code at https://getcourier.dev/mcp.
Choose MailSlurp if
- You need SMS or phone numbers. MailSlurp provisions real numbers for SMS, OTP and MFA tests. GetCourier is email only.
- You test how email looks and lands. Device previews, audits, inbox placement, warmup and domain monitoring are MailSlurp products; GetCourier has none of them.
- You want a mature SDK and framework ecosystem. MailSlurp lists SDK libraries and integrations for Playwright, Cypress, Selenium, k6 and JMeter, and common email platforms.
- You need SMTP, IMAP or a connected Gmail or Outlook mailbox.
- You buy through a card and a plan. Monthly or annual billing is easier to approve than prepaid crypto credits.
When not to use GetCourier
- You need SMS, previews or deliverability testing. Use MailSlurp or a similar suite.
- You need a card, an invoice or team seats. GetCourier is prepaid credits in USDC on Base or BTC, or x402, with one account key.
- Bulk or marketing email. Out of scope: sending is capped at 50 recipients per inbox per day.
- Long-lived inboxes at scale. Free inboxes last 72 hours; paid inboxes 72 hours or 30 days.
FAQ
Does MailSlurp have a free plan?
Its pricing page (read 2026-11-03) lists paid plans, from US$49 a month for Messaging APIs (US$529 a year), each with a 7-day trial that requires a card. Its homepage has a Start free button; what that includes beyond the trial is not stated on the pricing page.
Does MailSlurp have an MCP server?
Its homepage lists AI agents with email and SMS through API and MCP access, and it has MCP documentation. GetCourier also hosts an MCP server at https://getcourier.dev/mcp that needs no key for the free path.
Can an AI agent get a GetCourier inbox without signing up?
Yes. One unauthenticated POST to https://getcourier.dev/alias returns an address and a read_token. Free inboxes last 72 hours and are limited to 3 an hour and 5 a day per IP.
What does MailSlurp offer that GetCourier does not?
SMS and phone numbers, email device previews, email audits, inbox placement tests, warmup, domain monitoring, connected Gmail or Outlook mailboxes, SMTP and IMAP access, and team features. GetCourier is a small receive-and-reply inbox for agents and treats most of that as non-goals.