# MailerSend L1 · Needs a person MailerSend is an email infrastructure service for sending transactional email, SMS and WhatsApp messages through an API, a command-line tool and an MCP server. **Can an AI agent use MailerSend? No.** Our agent couldn't get into MailerSend on its own. Category: Email infrastructure · Connects by: MCP, API, CLI, SDK · Agent payments: None found · Driven: 27 Oct 2026 **How to connect** - MCP server URL: `https://mcp.mailersend.com/mcp` (streamable HTTP, documented). Source: https://mcp.mailersend.com/mcp - Docs page: `https://developers.mailersend.com/` (tested in our drive). Source: https://developers.mailersend.com/ **Level 1: Needs a person.** Agents can't get in on their own. - Got in by: A person sets it up (Not on its own in its last 2 drives) - Got as far as: Sign up (Use, Pay and Leave not reached) - To reach L2: Let an agent sign up on its own. 2 drives on one day, awaiting confirmation [What the levels mean](https://agentdrives.com/method/levels?via=md) ## From finding it to leaving What an agent managed without a person, at each step. 1. **Find**: On its own. Docs it can act on: llms.txt and an MCP server. 84 doc pages read. 2. **Get in**: Stopped. Can't sign up. A visible human-check on the sign-up form; other sign-ups only through Google, Apple, Microsoft or GitHub. Stopped here. 3. **Use**: Not reached. Tasks need an account. 4. **Pay**: Not reached. Buying needs an account. 5. **Leave**: Not reached. Nothing to cancel or delete. ## Getting in None of the 8 ways in worked without a person. Where it stopped: **Email and password**. A visible human-check on the sign-up form; other sign-ups only through Google, Apple, Microsoft or GitHub. - Both kinds of agent (On a server, or in its own browser): No. Signing up needs a person: it asks for a bot check. - Signed agent (Known to Cloudflare): Partly. The sign-up page opens. The check on the form still applies. | Way in | What happened | |---|---| | Email and password | Stopped by a CAPTCHA | | CLI code login | Stopped: The consent page needs an account | | Sign-in for apps (OAuth, MCP) | Stopped: The consent page needs an account | | Continue with GitHub | Not tried: Not part of this drive | | Continue with Google | Not tried: Not part of this drive | | Continue with Microsoft | Not tried: Not part of this drive | | Continue with Apple | Not tried: Not part of this drive | | Company single sign-on | Not tried: Needs a person's account | - Crawlers: **robots.txt asks crawlers to stay off sign-up and the API.** Nothing to fix. It keeps these pages out of search and doesn't stop agents signing up. [How agents get past bot checks](https://agentdrives.com/guides/let-signed-agents-past-your-bot-check.md?via=md) ## What an agent can do with MailerSend No task was tried: our agent couldn't get into MailerSend. Core tasks MailerSend offers an agent: - Send a transactional email (API, MCP) - Send an email from a drag & drop or HTML template (API, MCP) - Schedule an email to send later (API, MCP) - Send a batch/bulk email (API) - Send a transactional SMS (API, MCP) - Send a WhatsApp message (API, MCP) - Validate email addresses (single or bulk list) (API) - Add and verify a sending domain (API, MCP) What it can't do, and why: - Send email, SMS or WhatsApp messages: Not reached: there was no account. 18 more tasks it offers: - Receive and route inbound email (API) - Register and manage a webhook (API, MCP) - Manage suppressions (bounces, unsubscribes, spam complaints, blocklist) (API) - Read delivery and engagement events for an email (API, MCP) - Track opens and clicks on sent emails (API) - Create and edit an email template (API) - Split-test a template (Web app) - Translate a template into another language (Web app) - Monitor DMARC authentication reports for a domain (Web app) - Monitor domains/IPs against email blocklists (Web app) - Collect a survey response via email (Web app) - Manage files used in templates (Web app) - Read API/SMTP activity logs (API) - Invite a team member and set their role/permissions (Web app) - Create an API key (API) - Remove MailerSend branding from emails (Web app) - Set up a dedicated sending IP (Web app) - Restrict account access by IP allowlist (Web app) **Surface audit:** 391 documented operations, 3 run, 3 passed, 388 blocked (sandbox or plan limits). ## How an agent connects MCP, API, CLI, SDK and llms.txt found. Agent surfaces: API documented · MCP documented · CLI tested · SDK documented · Docs tested · Agent payments none found. Issues found: 1. - **MCP server**: Listed, not tested. Official server. Remote server, OAuth (DCR); docs list 127 tools when driven. Sign-in needed to see its tools. https://mcp.mailersend.com/mcp (127 tools across its docs) - **API**: Listed, not tested. REST at api.mailersend.com/v1, 142 documented operations. (142 operations across its docs) - **OpenAPI**: None found. none published. - **CLI**: 3 tested. official mailersend CLI 2.0.0, 116 commands. (108 commands across its docs) - **SDK**: Listed, not tested. Node.js 3.6.0, PHP, Python, Go, Ruby, Java. (6 methods across its docs) - **llms.txt**: Yes. https://www.mailersend.com/llms.txt - **Agent payments**: None found. The checkout wasn't reached. - **Docs**: Complete. Covers getting started, auth, error codes and code examples. https://developers.mailersend.com/ (84 pages read) [The standards](https://agentdrives.com/standard) ## Tips for agent builders - Read developers.mailersend.com/llms-full.txt or any docs page with Accept: text/markdown: the whole API reference comes back as Markdown. - Once a person has an account, ask for a scoped API token (Dashboard > API tokens) or OAuth via the MCP server at https://mcp.mailersend.com/mcp; the CLI OAuth login needs a browser on the same machine (callback 127.0.0.1:19821). - Sandbox mode sends only to 2 recipients until the account is approved; send tests to your own addresses. ## How MailerSend compares In Email infrastructure: 2 of the 8 products we drove in Email infrastructure are higher; 5 others share L1. - [AgentMail](https://agentdrives.com/tools/agentmail.md?via=md): L5, Gets in on its own - [Plunk](https://agentdrives.com/tools/useplunk.md?via=md): L2, Gets in on its own - **MailerSend** (this page): L1, Can't sign up on its own - [Mailgun](https://agentdrives.com/tools/mailgun.md?via=md): L1, Can't sign up on its own - [Mailtrap](https://agentdrives.com/tools/mailtrap.md?via=md): L1, Can't sign up on its own - [Postmark](https://agentdrives.com/tools/postmarkapp.md?via=md): L1, Can't sign up on its own - [Resend](https://agentdrives.com/tools/resend.md?via=md): L1, Can't sign up on its own - [SendGrid](https://agentdrives.com/tools/sendgrid.md?via=md): L1, Can't sign up on its own [All 8 in Email infrastructure](https://agentdrives.com/categories/email-infrastructure?via=md) Sorted by level, then work done, then time to the first call. [How we rank](https://agentdrives.com/method?via=md#order) On our standard (10 criteria: against other email infrastructure products where we measured 5 or more, otherwise against every product we measured): - [Pages fit one fetch](https://agentdrives.com/standard#docs-08): **Ahead of most** 3 of 5 others (email infrastructure products) lower, 2 the same. - [Docs an agent can navigate](https://agentdrives.com/standard#docs-11): **Ahead of most** 3 of 5 others (email infrastructure products) lower, 2 the same. - [Sign-in for agents acting for a person](https://agentdrives.com/standard#in-08): **Level with most** 64 of 119 others (every product) the same, 55 lower. - [Fast to the first call](https://agentdrives.com/standard#in-03): **Level with most** 71 of 85 others (every product) the same, 14 lower. - [Prices an agent can read](https://agentdrives.com/standard#find-06): **The same as all** 5 others (email infrastructure products). - [A path written for agents](https://agentdrives.com/standard#docs-10): **Level with most** 3 of 5 others (email infrastructure products) the same, 1 lower, 1 higher. - [WebMCP tools on the web app](https://agentdrives.com/standard#proto-02): **Level with most** 91 of 93 others (every product) the same, 2 higher. - [Every way in works for an agent](https://agentdrives.com/standard#in-11): **Level with most** 3 of 5 others (email infrastructure products) the same, 2 higher. - [The best way in is built for agents](https://agentdrives.com/standard#in-12): **Level with most** 3 of 5 others (email infrastructure products) the same, 2 higher. - [Export before leaving](https://agentdrives.com/standard#leave-03): **Level with most** 3 of 5 others (email infrastructure products) the same, 2 higher. [How each criterion is graded](https://agentdrives.com/standard) ## For the team behind MailerSend **9 things to fix for agents.** Agent blockers: 1 found · Agent surfaces: no issues found. Safety review: 1 issue found. Agents get stuck at Get in. Prove MailerSend is yours, then see where each issue is, read your safety findings and ask for a free drive after a fix. How to fix each one comes with the Audit. - Find: Clear - Get in: Blocks agents - Use: Not reached - Pay: Not reached - Leave: Not reached [Claim MailerSend, free](https://agentdrives.com/app/products?add=mailersend.com&ref=listing) · [What a drive covers](https://agentdrives.com/method?via=md) ## Where MailerSend fits - Category: [Communication APIs](https://agentdrives.com/categories/communication?via=md), [Email infrastructure](https://agentdrives.com/categories/email-infrastructure?via=md) - Wall: [Bot checks](https://agentdrives.com/access/get-in/bot-checks) (kept our agent out), [Cloudflare bot check](https://agentdrives.com/vendors/cloudflare) (the check, and every product we met it at), [Let signed AI agents past your bot check](https://agentdrives.com/guides/let-signed-agents-past-your-bot-check?via=md) (fix guide) - Standards: [MCP](https://agentdrives.com/standards/mcp) (tools an agent can call), [llms.txt](https://agentdrives.com/standards/llms-txt) (its docs, listed for agents) - Steps: [Find](https://agentdrives.com/access/find), [Get in](https://agentdrives.com/access/get-in) (stopped here), [Use](https://agentdrives.com/access/use), [Pay](https://agentdrives.com/access/pay), [Leave](https://agentdrives.com/access/leave) - Rivals: [Mailgun](https://agentdrives.com/tools/mailgun?via=md) (L1), [Mailtrap](https://agentdrives.com/tools/mailtrap?via=md) (L1), [Postmark](https://agentdrives.com/tools/postmarkapp?via=md) (L1) ## Cited in 1 article - [CLI for AI agents: 11 of 14 databases have one](https://agentdrives.com/research/which-kinds-of-software-give-ai-agents-a-cli-or-mcp-server?via=md) Data: [JSON](https://agentdrives.com/api/tools/mailersend.json?via=md) · [Markdown](https://agentdrives.com/tools/mailersend.md?via=md) · [History](https://agentdrives.com/tools/mailersend/history?via=md) · [Atom](https://agentdrives.com/feeds/tools/mailersend.atom) · [JSON Feed](https://agentdrives.com/feeds/tools/mailersend.json) · licence [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/) **Found an error?** [Tell us on this page](https://agentdrives.com/tools/mailersend?via=md#correct) or read [how corrections work](https://agentdrives.com/corrections?via=md).