Mailsac API

Name: Mailsac API API
Brand: Mailsac API
Availability: InStock

★ Only Publicly Available OpenAPI DocumentCommunicationsEmail DeliveryapiKey16 EndpointsREST

For Agents

Reserve disposable email addresses, fetch incoming messages, and subscribe to inbound-mail webhooks for automated email testing. Useful for agents that verify sign-up confirmations, password resets, and OTP codes.

Connect the Mailsac API to your agent

Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Mailsac 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.

Install Jentic One Beta (Self-Hosted)

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

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 Mailsac API API.

Reserve a private email address and release it when the test run finishes

Pull plain text, HTML, and raw SMTP bodies for a specific message ID

List every message delivered to an inbox and delete them in bulk between test runs

Validate an email address before sending a verification mail to it

GET STARTED

Start building with Mailsac API API

Explore with Jentic

View OpenAPI Document

Jentic publishes the only available OpenAPI document for Mailsac API, keeping it validated and agent-ready.

Jentic publishes the only available OpenAPI specification for Mailsac API, keeping it validated and agent-ready. Mailsac provides disposable and reserved email inboxes for development and QA, exposing endpoints to fetch incoming messages, retrieve raw SMTP and parsed bodies, validate addresses, and register webhooks for inbound events. The 16-endpoint API covers address reservation, message listing and deletion, attachment-aware content retrieval, and webhook subscription so automated tests can drive sign-up flows end to end. Authentication uses the Mailsac-Key header on each request.

Use Cases

Patterns agents use Mailsac API API for, with concrete tasks.

★ Sign-up Confirmation Testing

End-to-end tests of registration flows need a real inbox that the application under test can email. Mailsac provides reserved disposable addresses and a polling endpoint for the inbox so a test runner can submit a sign-up form, wait for the confirmation email to land, parse the verification link out of the body, and follow it to complete account creation. Setup takes minutes per test environment.

Reserve qa-signup-001@mailsac.com, submit a sign-up form, poll GET /api/addresses/{email}/messages until the verification email arrives, then extract the link from the body.

OTP and Password Reset Verification

QA suites that exercise password reset and one-time-code flows need to read back the codes the application sends. Mailsac exposes plain text and HTML bodies for any message in a reserved inbox, so an agent can request a reset, fetch the latest message, parse the OTP from the body, and feed it into the next step of the flow. Header inspection helps assert SPF, DKIM, and routing in the same run.

Trigger a password reset for user@example.com, fetch the most recent message at the Mailsac inbox, parse the 6-digit OTP, and submit it to the reset endpoint.

Webhook-Driven Inbound Mail Processing

Long-running test environments and inbound-mail features need push delivery rather than polling. Mailsac webhooks fire when a new message arrives at a reserved address, sending the message metadata to a chosen URL. Agents can register a webhook on a per-address basis and receive immediate notification, removing the need for polling loops and reducing test latency.

Call POST /api/addresses/{email}/webhooks to register https://my-app/inbound on the reserved Mailsac address and verify the next test message triggers the callback.

AI Agent Email Verification Loop

Agents that complete onboarding flows on behalf of users need to read confirmation emails as part of the loop. Through Jentic, an agent searches for the Mailsac operation, loads the input schema, and fetches the latest message body in three calls without manual API onboarding. The agent never holds the raw Mailsac key — Jentic injects it from the vault at execute time.

Use Jentic search 'fetch messages from disposable inbox', load the schema for GET /api/addresses/{email}/messages, and execute against the reserved address to retrieve the confirmation email.

Key Endpoints

16 endpoints — jentic publishes the only available openapi specification for mailsac api, keeping it validated and agent-ready.

METHOD

PATH

DESCRIPTION

GET

/api/addresses/{email}/messages

List messages for an email address

GET

/api/addresses/{email}/messages/{messageId}

Get a specific message metadata

GET

/api/text/{email}/{messageId}

Get plain text content of a message

GET

/api/raw/{email}/{messageId}

Get raw SMTP message

POST

/api/addresses/{email}

Reserve an email address

POST

/api/addresses/{email}/webhooks

Create a webhook for an email address

GET

/api/validations/{email}

Validate an email address

GET

/api/addresses/{email}/messages

List messages for an email address

GET

/api/addresses/{email}/messages/{messageId}

Get a specific message metadata

GET

/api/text/{email}/{messageId}

Get plain text content of a message

GET

/api/raw/{email}/{messageId}

Get raw SMTP message

POST

/api/addresses/{email}

Reserve an email address

Why though Jentic?

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

Credential isolation

The Mailsac API key is stored encrypted in the Jentic vault. Agents receive a scoped execution token and the Mailsac-Key header is injected server-side — the raw key never enters the agent's context.

Intent-based discovery

Agents search by intent (e.g., 'fetch messages from disposable inbox') and Jentic returns the matching Mailsac operations with their input schemas, so the agent calls the right endpoint without browsing docs.

Time to first call

Direct Mailsac integration: half a day to wire up auth, polling, and webhook handlers. Through Jentic: under 30 minutes — search, load, execute.

Related APIs

Alternatives and complements available in the Jentic catalogue.

Complementary

mailsac API Specification

The fuller 47-endpoint Mailsac spec covering domains, attachments, account, and bulk address operations.

Choose this when you need domain ownership, bulk address reservation, or attachment endpoints not present in the 16-endpoint spec.

Alternative

Mailtrap Email Sending API

Mailtrap provides a sandbox SMTP and sending API used for similar email testing scenarios.

Choose Mailtrap when you need to capture outbound email in a sandbox rather than receive at a public disposable address.

Complementary

SendGrid Alerts API

SendGrid handles outbound transactional sending while Mailsac receives and verifies the resulting messages.

Pair SendGrid for production sending with Mailsac for inbox-side test verification.

FAQs

Specific to using Mailsac API API through Jentic.

Why is there no official OpenAPI spec for Mailsac API?

Mailsac does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call Mailsac 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 Mailsac API use?

Mailsac uses an API key passed in the Mailsac-Key request header on every call. When you run Mailsac through Jentic the key is stored encrypted in the Jentic vault and injected at execution time, so agents never see the raw value in their context.

Can I read the body of a confirmation email with the Mailsac API?

Yes. Call GET /api/text/{email}/{messageId} for plain text, GET /api/body/{email}/{messageId} for sanitized HTML, or GET /api/raw/{email}/{messageId} for the original SMTP message including headers and attachments.

How do I get notified when a new message arrives at a Mailsac inbox?

Register a webhook on a reserved address with POST /api/addresses/{email}/webhooks and Mailsac will POST message metadata to your URL on arrival, removing the need to poll GET /api/addresses/{email}/messages.

What are the rate limits for the Mailsac API?

Rate limits are not declared in the OpenAPI spec — they depend on your Mailsac plan. Check your account dashboard at mailsac.com for current limits before driving high-volume test runs.

How do I fetch the latest message for an inbox through Jentic?

Run pip install jentic, then search for 'list messages from disposable inbox', load the schema for GET /api/addresses/{email}/messages, and execute with the reserved address. Jentic returns the message list without the agent ever handling the API key.