Mailosaur

Mailosaur Files API

Operations for downloading the raw content associated with a message — file attachments, the full EML source of an email, and rendered email previews.

GitHub OpenAPI

Operations 3

Each operation below carries the questions people ask an LLM about it and the instructions they give an agent to run it. Generated by API Evangelist overlay

GET /api/files/attachments/{attachmentId} Download an email attachment · Download an attachment #
Ask an LLM
“How do I download a file attached to a test email?”
“Can I fetch an attachment's contents to check the invoice PDF my app sent?”
Tell an agent
Download attachment {attachmentId}.
Save the attached file {attachmentId} so I can inspect it.
GET /api/files/email/{messageId} Download an email as an EML file · Download email as EML #
Ask an LLM
“Can I export a captured email as a raw .eml file?”
“How do I get the full original source of a test email?”
Tell an agent
Download message {messageId} as an EML file.
Export the raw email source of {messageId}.
GET /api/files/screenshots/{previewId} Download an email client preview screenshot · Download an email preview screenshot #
Ask an LLM
“How do I download the screenshot of my email rendered in a real email client?”
“Why does the preview screenshot download return 202 instead of an image?”
Tell an agent
Download preview screenshot {previewId}.
Get the rendered image for email preview {previewId} once it is ready.

Documentation

📖
Documentation
https://mailosaur.com/docs/api

Specifications

⚙
OpenAPI
https://raw.githubusercontent.com/api-evangelist/mailosaur/refs/heads/main/openapi/mailosaur-files-api-openapi.yml

Other Resources

🔗
Overlay
https://raw.githubusercontent.com/api-evangelist/mailosaur/refs/heads/main/overlays/mailosaur-files-api-overlay.yaml
🔗
PostmanCollection
https://www.postman.com/mailosaur/mailosaur/documentation/6961255-6cc72dff-f576-451a-9023-b82dec84f95d

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OpenAPI Specification

mailosaur-files-api-openapi.yml Raw ↑ 
openapi: 3.2.0
info:
  title: Mailosaur Files API
  description: REST API for email and SMS testing. Provides endpoints for managing test inboxes (servers), retrieving and searching messages, running deliverability checks, generating OTPs for authenticator testing, and accessing account usage data. All requests authenticate via HTTP Basic Auth using an API key.
  version: 1.0.0
  contact:
    name: Mailosaur Support
    url: https://mailosaur.com/docs/api
  termsOfService: https://mailosaur.com/terms
  license:
    name: Commercial
    url: https://mailosaur.com/terms
servers:
- url: https://mailosaur.com
  description: Mailosaur production API
security:
- basicAuth: []
tags:
- name: Files
  description: Operations for downloading the raw content associated with a message — file attachments, the full EML source of an email, and rendered email previews.
paths:
  /api/files/attachments/{attachmentId}:
    get:
      operationId: getAttachment
      summary: Download an attachment
      description: Downloads a single attachment.
      tags:
      - Files
      parameters:
      - name: attachmentId
        in: path
        required: true
        description: The identifier for the required attachment.
        schema:
          type: string
      responses:
        '200':
          description: The attachment binary content.
          content:
            application/octet-stream:
              schema:
                type: string
                format: binary
  /api/files/email/{messageId}:
    get:
      operationId: getEmailFile
      summary: Download email as EML
      description: Downloads an EML file representing the specified email.
      tags:
      - Files
      parameters:
      - $ref: '#/components/parameters/messageId'
      responses:
        '200':
          description: The raw EML content of the email.
          content:
            message/rfc822:
              schema:
                type: string
                format: binary
  /api/files/screenshots/{previewId}:
    get:
      operationId: getEmailPreview
      summary: Download an email preview screenshot
      description: Downloads a screenshot of your email rendered in a real email client. Simply supply the unique identifier for the required preview. Returns 202 while the preview is still being generated.
      tags:
      - Files
      parameters:
      - name: previewId
        in: path
        required: true
        description: The identifier of the email preview to be downloaded.
        schema:
          type: string
      responses:
        '200':
          description: The preview screenshot image.
          content:
            image/png:
              schema:
                type: string
                format: binary
        '202':
          description: The preview is still being generated. Poll again shortly.
components:
  parameters:
    messageId:
      name: messageId
      in: path
      required: true
      description: The unique identifier of the message.
      schema:
        type: string
  securitySchemes:
    basicAuth:
      type: http
      scheme: basic
      description: HTTP Basic Auth using your Mailosaur API key as the username and an empty password, or your API key as both username and password.