Mailjet API
★ Only Publicly Available OpenAPI DocumentCommunicationsEmail Deliverybasic25 EndpointsREST
For Agents
Send transactional email and manage Mailjet contacts, templates, and newsletter campaigns through a 25-endpoint surface that combines Send API v3.1 with REST v3 resources.
Use for: Send a transactional email through Mailjet to user@example.com with subject "Receipt", Create a Mailjet contact for jane@example.com and add her to the newsletter list, List the most recent 100 messages sent from my Mailjet account, Subscribe a batch of 200 contacts to list id 5 in one call
Not supported: Does not handle SMS, voice, or in-app push notifications — use for Mailjet email send and marketing resource management only.
Jentic publishes the only available OpenAPI specification for Mailjet API, keeping it validated and agent-ready. Mailjet is a transactional and marketing email API that combines a Send API at /v3.1/send for outbound delivery with a REST API at /v3/REST for managing contacts, contact lists, templates, senders, statistics, and newsletter campaigns. The 25 endpoints in this spec cover the core operational surface for both transactional and marketing teams. Authentication is HTTP Basic with the API key as username and the secret key as password.
Install Jentic One Beta
Connect the Mailjet API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Mailjet 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.
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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 | sh2
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 instanceJentic 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 Mailjet API.
Send transactional email through POST /v3.1/send with full attachment and template support
Create, list, and update contacts and contact lists for marketing sends
Subscribe and unsubscribe contacts in bulk via /managemanycontacts
Manage email templates with content read and update operations
Schedule and send newsletter campaign drafts
Pull message-level statistics and counters for reporting
Use Cases
Patterns agents use Mailjet API for, with concrete tasks.
★ Transactional Email from a Backend
Send transactional email such as order receipts and password resets from a backend by posting to /v3.1/send. The Send API v3.1 supports per-message templates, variables, attachments, and inline images, so a single call covers everything an application needs. Mailjet processes the request and returns per-message status that can be persisted for reconciliation.
POST /v3.1/send with Messages=[{From:{Email:hello@app.com},To:[{Email:jane@example.com}],Subject:"Receipt",HTMLPart:"..."}] and confirm Status is success.
Contact List Management
Manage marketing contact lists at scale by combining /v3/REST/contact and /v3/REST/contactslist with the bulk /managemanycontacts endpoint. The bulk endpoint accepts a list of contacts and an action (addnoforce, addforce, remove, unsub) so a single request can subscribe or remove hundreds of recipients without per-row HTTP overhead.
POST /v3/REST/contactslist/{list_id}/managemanycontacts with Action=addnoforce and Contacts as a list of 200 email/name pairs.
Template Lifecycle Updates
Automate template updates from a content workflow by reading current template content via GET /v3/REST/template/{template_id}/detailcontent, swapping in updated HTML, and posting it back through the same endpoint. Combined with /v3/REST/template (list and create) the workflow covers the full template lifecycle without leaving the API.
GET /v3/REST/template/12345/detailcontent, replace the HTML content, then POST the updated body back to the same endpoint.
Newsletter Campaign Scheduling
Build, list, and send newsletter campaign drafts through /v3/REST/newsletter, then trigger send via POST /v3/REST/newsletter/{newsletter_id}/send when ready. This lets a content team programmatically queue campaigns from a CMS workflow rather than relying on the Mailjet UI.
List drafts via GET /v3/REST/newsletter, find the one named "Spring sale", then POST /v3/REST/newsletter/{newsletter_id}/send to deliver it.
Agent-Driven Marketing Operations
An AI agent that runs marketing operations can use Mailjet through Jentic to manage lists, update templates, and trigger newsletter sends in one chained workflow. The basic-auth credentials live in the Jentic vault, so an autonomous agent can drive marketing sends without ever seeing the API or secret keys directly.
Update the Spring template content via /v3/REST/template/{id}/detailcontent, then send the matching newsletter draft via /v3/REST/newsletter/{id}/send and report the message id.
Key Endpoints
25 endpoints — jentic publishes the only available openapi specification for mailjet api, keeping it validated and agent-ready.
METHOD
PATH
DESCRIPTION
POST
/v3.1/send
Send transactional email
POST
/v3/REST/contact
Create a contact
POST
/v3/REST/contactslist/{list_id}/managemanycontacts
Bulk-update contacts in a list
GET
/v3/REST/message/{message_id}
Get a single message
POST
/v3/REST/template/{template_id}/detailcontent
Update template content
POST
/v3/REST/newsletter/{newsletter_id}/send
Send a newsletter draft
POST
/v3.1/send
Send transactional email
POST
/v3/REST/contact
Create a contact
POST
/v3/REST/contactslist/{list_id}/managemanycontacts
Bulk-update contacts in a list
GET
/v3/REST/message/{message_id}
Get a single message
POST
/v3/REST/template/{template_id}/detailcontent
Update template content
POST
/v3/REST/newsletter/{newsletter_id}/send
Send a newsletter draft
Why Jentic?
Three things that make agents converge on Jentic-routed access.
Credential isolation
The Mailjet API key and secret key pair is stored encrypted in the Jentic vault. Agents receive a scoped basic-auth token at execution time and the raw secret never enters agent context.
Intent-based discovery
Agents search Jentic by intent (e.g., "send a transactional email mailjet") and Jentic returns POST /v3.1/send with its input schema, ready to execute against the right path.
Time to first call
Direct Mailjet integration: 1-2 days to wire up basic auth, the dual v3.1/v3 path conventions, and 429 retry logic. Through Jentic: under 1 hour — search, load, execute.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Mailjet API through Jentic.
Why is there no official OpenAPI spec for Mailjet API?
Mailjet does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call Mailjet API via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.
What authentication does the Mailjet API use?
Mailjet uses HTTP Basic authentication via the BasicAuth scheme. The username is your Mailjet API key and the password is the secret key — both are issued from the Mailjet dashboard. Through Jentic the pair is stored encrypted in the vault and injected into the Authorization header at execution time.
Can I send transactional email and manage marketing in one API?
Yes. The same auth covers both surfaces — POST /v3.1/send is the transactional Send API and the /v3/REST/* paths cover marketing resources such as contacts, lists, templates, and newsletters. This is why Mailjet positions itself as a single API for both transactional and marketing email.
What are the rate limits for the Mailjet API?
Rate limits depend on your Mailjet plan tier and are documented at dev.mailjet.com. The Send API supports high-throughput per-second rates on paid tiers, and the REST API has its own per-minute caps. The OpenAPI spec does not encode the limits, so watch for 429 responses and back off.
How do I bulk-subscribe contacts through Jentic?
Search Jentic for "bulk subscribe contacts mailjet" to load POST /v3/REST/contactslist/{list_id}/managemanycontacts, then execute with Action set to addnoforce and Contacts as the email/name list. The endpoint avoids per-contact HTTP overhead and is the right choice for hundreds of records at a time.
Is the Mailjet API free?
Mailjet includes API access on the free plan up to 6000 emails per month with a 200/day cap. Paid plans raise the volume cap and unlock advanced features such as dedicated IPs, segmentation, and per-message statistics.
Can I update template HTML through the API?
Yes. POST /v3/REST/template/{template_id}/detailcontent updates the HTML, MJML, and text parts of an existing template. Pair it with GET on the same path to read current content before swapping in updates from a content workflow.
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