Install Jentic One Beta

Connect the Mailcheer API to your agent

Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Mailcheer 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://jentic.com/install.sh?src=apis&api=%2Fapis%2Fmailcheer.com%2Fmailcheer" | sh

Step 2: Agent machine

# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fmailcheer.com%2Fmailcheer" | 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 Mailcheer API.

Send a transactional email from a verified domain with reply_to, tags, attachments, and open or click tracking

Check delivery status of a sent email and verify addresses before writing to them

Upsert subscribers individually or up to 500 per batch, then add or remove tags

Draft a campaign, preview its audience, and start the send with an optional dry_run

GET STARTED

Start building with Mailcheer API

Explore with Jentic One

View OpenAPI Document

Use Cases

Patterns agents use Mailcheer API for, with concrete tasks.

★ AI agent sending transactional email through Jentic

An app's support agent needs to email a customer a receipt without the developer writing a mail client. Through Jentic it searches for 'send an email', loads the Mailcheer send operation, first reads GET /api/v1/me to find a verified domain and sender, then posts from, to, subject, and html. The API key is injected at call time and the 202 response confirms acceptance.

Call GET /api/v1/me to read verified domains, then POST /api/v1/emails with from 'Billing <billing@yourdomain.com>', to 'customer@example.com', subject 'Your September invoice', and html, then GET /api/v1/emails/{id} for status

Newsletter campaign from draft to send

A small team writes a monthly newsletter and wants it sent to tagged subscribers. Mailcheer creates the campaign as a draft with name, subject, preheader, and content, previews the audience a target would reach without creating a campaign, and starts the send, optionally as a dry_run first. Afterwards the full report and per-recipient status show what happened.

Call POST /api/v1/campaigns with name and subject, POST /api/v1/audience with the target tag to preview recipients, then POST /api/v1/campaigns/{id}/send with dry_run true before the real send

Subscriber sync from a signup form

New signups land in an app database and need to reach the mailing list. Mailcheer upserts a subscriber by email with firstName, lastName, tags, custom fields, and double_opt_in, or up to 500 subscribers in one batch call. Tags can be added or removed per person or across many subscribers at once.

Call POST /api/v1/subscribers/batch with a subscribers array of new signups, then POST /api/v1/tags/{tag}/subscribers to tag them as 'trial'

Compliance and list hygiene

Sending reputation depends on not mailing people who bounced, complained, or opted out. Mailcheer keeps a suppression list that refuses sends to listed addresses, verifies addresses before writing to them, and erases a person on a GDPR request. A bounce or complaint rate that is too high suspends sending, so hygiene matters before a campaign.

Call POST /api/v1/verify with an emails array, then POST /api/v1/suppression for each invalid address with a reason

Key Endpoints

37 endpoints — the mailcheer api sends transactional emails from your application and runs your subscriber lists and email campaigns from code.

METHOD

PATH

DESCRIPTION

POST

/api/v1/emails

Send an email

GET

/api/v1/emails/{id}

Get the status of an email

GET

/api/v1/me

Read key permissions, quota, and verified domains

POST

/api/v1/subscribers/batch

Upsert up to 500 subscribers

POST

/api/v1/campaigns

Create a campaign draft

POST

/api/v1/campaigns/{id}/send

Start a campaign send

GET

/api/v1/campaigns/{id}/stats

Get the full campaign report

POST

/api/v1/suppression

Suppress an address

POST

/api/v1/emails

Send an email

GET

/api/v1/emails/{id}

Get the status of an email

GET

/api/v1/me

Read key permissions, quota, and verified domains

POST

/api/v1/subscribers/batch

Upsert up to 500 subscribers

POST

/api/v1/campaigns

Create a campaign draft

POST

/api/v1/campaigns/{id}/send

Start a campaign send

GET

/api/v1/campaigns/{id}/stats

Get the full campaign report

POST

/api/v1/suppression

Suppress an address

Why Jentic?

What agents get from Jentic-routed access to this vendor.

Setup

Wiring Mailcheer by hand means choosing between bearer and X-Api-Key auth, reading verified domains before the first send, and honouring Retry-After on 429 and 423 responses. Through Jentic you install once, import Mailcheer from the API Directory, store the key once, and your agent calls it.

Permission scoping

Mailcheer puts the subscriber email, campaign id, and webhook id in the URL path, such as /api/v1/campaigns/{id}/send, so a rule can pin your agent to one campaign or one subscriber and the operations you pick. You choose the operations it may call, so ones like starting a campaign send, erasing a person, or deleting a tag are not included unless you add them.

Credential isolation

Your Mailcheer API key is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context.

Intent-based discovery

Agents search Jentic by intent such as 'send a transactional email' or 'add a subscriber', and Jentic returns the matching Mailcheer operation with its input schema so the agent calls the right endpoint without browsing the reference docs.

FAQs

Specific to using Mailcheer API through Jentic.

What authentication does the Mailcheer API use?

Mailcheer declares a workspace API key sent either as a bearer token in the Authorization header or in the X-Api-Key header, per its OpenAPI spec; the two are equivalent, so send one, not both. Keys start with mch_live_ or mch_test_ and carry scopes such as emails:send. GET /api/v1, the API map, needs no key. Through Jentic the key is stored by your own instance and attached at call time.

What are the rate limits for the Mailcheer API?

The Mailcheer OpenAPI spec states 600 requests per minute per key, with a 429 response beyond that and a Retry-After header in seconds. Monthly plan quota is reported on authenticated responses through the Mailcheer-Quota-Remaining and related headers.

Is there a Mailcheer MCP server?

Yes. Mailcheer offers an official MCP server that calls this same API. You can also connect Mailcheer directly through Jentic: your agent gets the full 37-endpoint surface without loading another server's tool definitions into its context, your key is injected at call time by your self-hosted instance instead of living in an MCP config, and your rules decide which operations the agent may call.

Can I test Mailcheer sends without emailing anyone?

Yes. A key that starts with mch_test_ checks every send like a live one, including verified from address and suppression list, and returns the same response, but nothing goes out and the quota is not touched. Simulated events still reach your webhooks marked as test.

How do I send an email through Jentic?

Search Jentic for 'send a transactional email', load the POST /api/v1/emails operation, and run it with from, to, subject, and html or text; from must be on a domain verified in the workspace, which GET /api/v1/me lists. To run it on your own infrastructure, install Jentic One from its GitHub repo.

Can I limit what my agent is allowed to do with the Mailcheer API?

Yes. For example, a rule that allows POST /api/v1/subscribers and POST /api/v1/subscribers/{email}/tags lets the agent add and tag signups while it cannot send a campaign, erase a subscriber, or delete a webhook. Jentic logs each call the agent makes, and Mailcheer key scopes add a second limit.

Mailcheer API

AI ReadinessAI-Aware (B-)62/100

See full scorecard

Official vendor OpenAPI document · agent-readyCommunicationsEmail Deliveryhttp (bearer), apiKey (X-Api-Key header)37 EndpointsREST

For Agents

Send transactional email and run subscriber lists and campaigns with Mailcheer: send from a verified domain, upsert and tag subscribers, draft and send campaigns, manage suppressions, and replay webhook deliveries.

Use for: I need to send an invoice email to a customer, Check whether my last email was delivered, Add a new signup to my subscriber list with a tag, Find all subscribers tagged as beta testers

Not supported: Does not send SMS, push notifications, or run a CRM. Use for transactional email, subscriber lists, and email campaigns only.

The Mailcheer API sends transactional emails from your application and runs your subscriber lists and email campaigns from code. A single send call delivers one message from a verified domain, with fields such as reply_to, tags, attachments, track_opens, and unsubscribe_url, and returns 202 once the message is accepted. Subscribers can be upserted one at a time or up to 500 per batch, tagged, unsubscribed, or erased for GDPR, while campaigns move from draft through an optional dry_run to a real send with full statistics. Suppressions, address verification, a tracking domain, and webhook subscriptions with a replayable delivery log complete the surface, and a test key that starts with mch_test_ simulates sends without delivering anything.

Jentic One on Github View OpenAPI Document

Show dimension breakdown

Foundational Compliance

Base layer of spec validity and structural soundness.

Grade: D+Signals: 4

92%

Lint Results

Aggregated quality score from linter diagnostics, weighted by severity.

100%

Resolution Completeness

Percentage of `$ref` references that resolve successfully.

Specification Validity

Checks whether the API description parses successfully and conforms to its declared specification (e.g., OpenAPI).

Structural Integrity

Structural correctness score based on schema issues using logarithmic dampening.

Developer Experience & Jentic Compatibility

Clarity, completeness, and ingestion readiness for developers and tooling.

Grade: BSignals: 4

10%

Example Density

How richly the API is illustrated with examples.

100%

Example Validity

Percentage of examples that conform to their schemas.

49%

Response Coverage

Percentage of operations with complete response definitions (success, client error, server error).

100%

Tooling Readiness

Health of API ingestion, bundling, and resolution within Jentic pipelines.

AI-Readiness & Agent Experience

Semantic breadth, depth, and agent comprehension for AI systems.

Grade: CSignals: 4

61%

Description Coverage

Coverage of descriptions across API elements.

Error Standardization

Coverage of RFC 9457 Problem Details for error responses.

100%

OperationId Quality

Coverage, uniqueness, and casing consistency of operationIds for AI inference.

64%

Summary Coverage

Coverage of summaries across operations/tags/info.

Agent Usability

Functional utility, complexity comfort, and AI orchestration readiness.

Grade: A+Signals: 1

94%

Complexity Comfort

Agent comfort level based on API operational and structural complexity.

Security

Trust, risk posture, and security compliance.

Grade: CSignals: 1

55%

Authentication Strength

Average quality of security schemes based on authentication method strength (weakest link for OAuth2).

AI Discoverability

Findability, semantic richness, and reasoning readiness.

Grade: A-Signals: 1

73%

Descriptive Richness

Clarity and depth of descriptions across API elements.

Connect the Mailcheer API to your agent

Capabilities

Start building with Mailcheer API

Use Cases

Key Endpoints

Why Jentic?

Related APIs

FAQs

Mailcheer API

Jentic AI Readiness Score

Mailcheer API

Foundational Compliance

Lint Results

Resolution Completeness

Specification Validity

Structural Integrity

Developer Experience & Jentic Compatibility

Example Density

Example Validity

Response Coverage

Tooling Readiness

AI-Readiness & Agent Experience

Description Coverage

Error Standardization

OperationId Quality

Summary Coverage

Agent Usability

Complexity Comfort

Security

Authentication Strength

AI Discoverability

Descriptive Richness