MailerSend API

Name: MailerSend API
Brand: MailerSend API
Availability: InStock

✓ Official Vendor SpecCommunicationsEmail Deliverybearer5 EndpointsREST

For Agents

Send transactional email — single or bulk — and pull per-domain activity reports through five endpoints with bearer-token auth.

Install Jentic One Beta

Connect the MailerSend API to your agent

Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the MailerSend API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.

Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.

Step 1: Jentic One Host machine

# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh

Step 2: Agent machine

# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh
jentic register       # connects your agent to your Jentic One instance

Jentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.

Capabilities

What an agent can do with MailerSend API.

Send a single transactional email through POST /email

Submit a bulk-email batch through POST /bulk-email and poll status

Pull per-domain activity (delivered, opened, clicked, bounced) for analytics

GET STARTED

Start building with MailerSend API

Explore with Jentic

View OpenAPI Document

Use Cases

Patterns agents use MailerSend API for, with concrete tasks.

★ Transactional Email from a SaaS App

Send signup confirmations, password resets, and notification emails from a product backend by calling POST /email with from, to, subject, and html fields. MailerSend handles MTA queuing, bounce processing, and IP reputation, so the backend only needs to construct the message and submit it. A single call typically returns a queued status within sub-second latency.

POST /email with from=hello@app.com, to=[{"email":"jane@example.com"}], subject="Welcome", and an html body, then verify the response includes a x-message-id header.

Bulk Notification Batches

Send up to several thousand notifications in a single POST /bulk-email call rather than firing one HTTP request per recipient. The returned bulk_email_id can be polled through GET /bulk-email/{bulkEmailId} to confirm full completion before the orchestrator marks the job done. This is the right pattern for daily digest emails or a one-off blast to a known list.

POST /bulk-email with a JSON array of 100 messages, then poll GET /bulk-email/{bulkEmailId} every 5 seconds until status is completed.

Activity Reconciliation

Reconcile MailerSend webhook events with the API by calling GET /activity/{domainId} for a domain or GET /activities/{activityId} for a specific event. Use this when an event might have been missed by a webhook listener or to backfill an analytics warehouse with delivered, opened, and clicked counts.

Call /activity/{domainId} for the last 24 hours, filter for events with type=hard_bounced, and write each into a Postgres bounces table.

Agent-Driven Operational Mail

An AI agent that handles incidents or operational workflows can send a structured email to an on-call rotation through MailerSend via Jentic, then poll activity to confirm delivery before closing the ticket. The bearer token sits in the Jentic vault, so the agent can be safely granted send rights without exposing credentials.

Send an incident summary email via POST /email to the on-call alias, then poll /activities/{activityId} until status is delivered before resolving the ticket.

Key Endpoints

5 endpoints — mailersend is a transactional email delivery api designed for product and notification email at scale.

METHOD

PATH

DESCRIPTION

POST

/email

Send a transactional email

POST

/bulk-email

Submit a bulk-email batch

GET

/bulk-email/{bulkEmailId}

Get bulk-email batch status

GET

/activity/{domainId}

List activities for a domain

GET

/activities/{activityId}

Get a single activity event

POST

/email

Send a transactional email

POST

/bulk-email

Submit a bulk-email batch

GET

/bulk-email/{bulkEmailId}

Get bulk-email batch status

GET

/activity/{domainId}

List activities for a domain

GET

/activities/{activityId}

Get a single activity event

Why Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

The MailerSend bearer token is stored encrypted in the Jentic vault and injected into the Authorization header at execution time. Agents never read or log the raw token.

Intent-based discovery

Agents search Jentic by intent (e.g., "send a transactional email") and Jentic returns POST /email with its input schema, so the agent can call the right endpoint without browsing the MailerSend docs.

Time to first call

Direct MailerSend integration: half a day to wire up bearer auth, schema handling, and 429 retry. Through Jentic: under 30 minutes — search, load, execute.

FAQs

Specific to using MailerSend API through Jentic.

What authentication does the MailerSend API use?

MailerSend uses bearer token authentication via the bearerAuth scheme. Generate the token from the MailerSend dashboard and send it in the Authorization header as Bearer {token}. Through Jentic the token is stored encrypted in the vault and injected at execution time.

Can I send bulk email in one request?

Yes. POST /bulk-email accepts an array of message objects and returns a bulk_email_id you poll via GET /bulk-email/{bulkEmailId} until status is completed. This is the right pattern for daily digests or one-off blasts to a known list.

What are the rate limits for the MailerSend API?

Rate limits depend on your MailerSend plan tier and are published at developers.mailersend.com. The default tier allows several thousand requests per hour. The OpenAPI spec does not encode the per-second cap, so watch for 429 responses and back off.

How do I send a transactional email through Jentic?

Search Jentic for "send a transactional email" and load POST /email. Execute with from, to, subject, and html fields populated. The response includes a x-message-id header you can correlate with /activities/{activityId}.

Is the MailerSend API free?

MailerSend includes an API quota on the free plan (currently 3000 emails per month). Higher plans raise the monthly cap and unlock advanced features such as dedicated IPs and a higher bulk-email batch size.

MailerSend API

Connect the MailerSend API to your agent

Capabilities

Start building with MailerSend API

Use Cases

Key Endpoints

Why Jentic?

Related APIs

FAQs