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MailerSend

MailerSend API

Yes. MailerSend publishes a public REST API with api-key auth. See mailersend.com/features/email-api for pricing details.

Auth: api-keySDKs: node, java
Open API docsTry MailerSend
Public REST API documentedAgent-readiness 4/10
Data from Buddy's database, auto-rechecked weekly

What is the MailerSend API?

The MailerSend API is a public REST interface to campaigns, contacts, segments, and automation workflows. Auth is handled with an API key in a header. Official SDKs cover node, java, which keeps boilerplate to a minimum.

Typical builds: scripts that sync subscribers from your product database, engagement dashboards that combine open rate with revenue attribution, and cron jobs that pause underperforming campaigns automatically.

For agent workflows, the API is the path of least resistance until MailerSend ships an MCP server. ask Claude which segments are growing fastest this quarter, have Cursor draft a 3-step welcome series for new ebook signups, and let Codex re-engage cold subscribers with personalised subject lines.

For the broader picture: MailerSend review, full pricing breakdown, .

HOOK IT TO YOUR STACK

Real MailerSend API calls you'll write

mailersend-apirest
#List campaigns from the last 30 days
GET/v3/campaigns?since=30d&fields=name,open_rate,clicks
200 OK · 12 campaigns
Black Friday Teaseropen 42.1%
Product launchopen 38.5%
Weekly digest #12open 27.0%
Welcome flow step 2open 61.3%
mailersend-apirest
#Create a new automation programmatically
POST/v3/automations
201 Created · automation_id: aut_8x
Statusdraft
Steps configured0
Estimated audience2,847
Push steps via PUT /automations/{id}/steps.
mailersend-apirest
#Add a contact and tag them in one call
POST/v3/contacts
201 Created · contact_id: c_4f12
Lifecycle stagesubscriber
Tags applied1
Triggers firedwelcome-series
TMB SCORE FOR MailerSendAuth: api-keyAgent fit: 4/10
Read review →

Endpoints illustrative. Confirm exact paths against the live API docs before integrating.

How much does the MailerSend API actually cost?

Verify on docs

MailerSend publishes an API, but per-tier gating wasn't extracted automatically.

  • Most likely scenario: API access is either included in all paid plans, or it's gated to higher tiers and we need to verify on the live docs page.
  • Until verified, treat the question "which plan unlocks the API" as open. Don't budget on the assumption it's free with the cheapest paid plan.

API at a glance

Auth method
api-key
SDK languages
node, java
OpenAPI spec
—
Webhooks
—
Structured outputs
—

What you can build with the MailerSend API

Three personas, three different shapes of build. Pick the row that matches how you actually ship.

SOLO DEV / FOUNDER

Glue MailerSend into your daily workflow

  • Pull a digest of campaign performance into your morning Slack
  • Trigger a one-off backfill when something looks off
  • Pipe data into your own SQLite for ad-hoc queries
Effort: A weekend, one Node or Python script
AGENCY / CONSULTANT

Sell MailerSend reporting at scale

  • White-label MailerSend data into client-branded dashboards
  • Run scheduled multi-account reports without logging into the MailerSend UI
  • Cross-reference with the rest of the client's stack (CRM, analytics, ad spend)
Effort: 1-2 weeks, hits multi-tenant auth quickly
IN-HOUSE ENGINEER

Production pipelines for MailerSend

  • Real-time sync into your warehouse on a cron
  • Custom alerts the dashboard's built-in alerting can't express
  • Backfill + idempotency handling for MailerSend data older than the dashboard exposes
Effort: Multi-week project, expect rate-limit tuning

Quickstart template

# Starter template — endpoint paths and SDK package names come from
# the MailerSend API docs: https://www.mailersend.com/features/email-api

curl -X GET "https://www.mailersend.com/<your-endpoint>" \
  -H "Authorization: Bearer $YOUR_API_KEY" \
  -H "Accept: application/json" | jq .

Template only. Endpoint paths, exact base URL, and auth header format come from mailersend.com/features/email-api.

Limits and gotchas

  • No OpenAPI spec — you write typed clients by hand or use a third-party generator on the docs HTML.
  • Official SDKs: node, java. Use them to skip auth boilerplate and get type safety.
  • Rate limits: always read the docs page before scaling — the published limit is usually lower than the practical one and overages can be expensive.
4/10

Agent-readiness verdict

Not ready for agent workflows. MailerSend has documented APIs with Node and Java SDKs, but lacks MCP integration, OpenAPI specs, and webhooks support—all critical for Claude/Cursor automation. You'd need to build custom tooling to make this work with agents.

Public API with docsMultiple SDK languages

MailerSend API FAQ

Does MailerSend have a public API?+
Yes — REST API at mailersend.com/features/email-api, auth via api-key.
What auth does the MailerSend API use?+
API key in a header — simplest to integrate, no OAuth dance.
Does MailerSend have official SDKs?+
Yes — official SDKs for node, java.

Sources

Joonas Rotko
Joonas RotkoAuthor & Founder of That Marketing Buddy

10+ years in digital marketing. I review marketing software for AI-stack fit: real pricing, MCP and API support, and how cleanly each tool drops into an AI agent workflow, cross-checked against verified data and real user feedback.

About meHow I review

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