> ## Documentation Index
> Fetch the complete documentation index at: https://inbound.new/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Add a sender to the mailbox spam block list

> Adds the address or @domain (removing it from the allow list if it was there). A list holds at most 1000 entries.



## OpenAPI

````yaml https://inbound.new/openapi.json post /api/e2/mailboxes/{id}/spam/block
openapi: 3.1.0
info:
  title: Inbound Email API
  description: >+

    # Inbound API


    The Inbound API allows you to manage email infrastructure programmatically -
    domains, email addresses, webhooks, and more.


    ## Authentication


    All API requests require a Bearer token in the Authorization header:


    ```bash

    curl -H "Authorization: Bearer YOUR_API_KEY" \
      https://inbound.new/api/e2/domains
    ```


    ## Base URL


    ```

    https://inbound.new/api/e2

    ```


    ## Quick Start


    1. **Create a domain** - Register your domain with Inbound

    2. **Configure DNS** - Add the provided DNS records to your domain

    3. **Create an email address** - Set up addresses to receive emails

    4. **Create an endpoint** - Configure where emails are delivered (webhook,
    forwarding, etc.)

  version: 2.0.0
servers:
  - url: https://inbound.new
    description: Production API server
security:
  - bearerAuth: []
tags:
  - name: Webhooks
    description: Webhooks sent by Inbound to your configured endpoints when events occur.
  - name: Emails
    description: >-
      Send, list, and manage emails. Supports immediate sending, scheduling,
      replies, and retry functionality.
  - name: Mail
    description: >-
      Inbox and thread views for received emails. Filter by domain, address, or
      search.
  - name: Domains
    description: >-
      Manage domains for sending and receiving emails. Domains must be verified
      via DNS before use.
  - name: Endpoints
    description: >-
      Configure where incoming emails are delivered - webhooks, email
      forwarding, or custom handlers.
  - name: Email Addresses
    description: Create and manage email addresses on your verified domains.
  - name: Attachments
    description: Download email attachments using authenticated requests.
paths:
  /api/e2/mailboxes/{id}/spam/block:
    post:
      tags:
        - Mailboxes
      summary: Add a sender to the mailbox spam block list
      description: >-
        Adds the address or @domain (removing it from the allow list if it was
        there). A list holds at most 1000 entries.
      operationId: postApiE2MailboxesByIdSpamBlock
      parameters:
        - name: id
          in: path
          required: true
          schema:
            type: string
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                pattern:
                  minLength: 2
                  maxLength: 255
                  description: >-
                    An exact sender address (`alice@example.com`) or a whole
                    domain (`@example.com`). Case-insensitive.
                  type: string
              required:
                - pattern
          application/x-www-form-urlencoded:
            schema:
              type: object
              properties:
                pattern:
                  minLength: 2
                  maxLength: 255
                  description: >-
                    An exact sender address (`alice@example.com`) or a whole
                    domain (`@example.com`). Case-insensitive.
                  type: string
              required:
                - pattern
          multipart/form-data:
            schema:
              type: object
              properties:
                pattern:
                  minLength: 2
                  maxLength: 255
                  description: >-
                    An exact sender address (`alice@example.com`) or a whole
                    domain (`@example.com`). Case-insensitive.
                  type: string
              required:
                - pattern
      responses:
        '200':
          description: Response for status 200
          content:
            application/json:
              schema:
                type: object
                properties:
                  level:
                    description: >-
                      The mailbox's junk filter level; null uses the account's
                      level
                    nullable: true
                    anyOf:
                      - description: >-
                          off: never mark mail as junk automatically (Guard junk
                          rules still apply). lenient: only clear spam or
                          threats. standard (default): likely spam or threats.
                          strict: also possible spam or threats.
                        anyOf:
                          - const: 'off'
                            type: string
                          - const: lenient
                            type: string
                          - const: standard
                            type: string
                          - const: strict
                            type: string
                      - type: 'null'
                  effectiveLevel:
                    type: string
                    enum:
                      - 'off'
                      - lenient
                      - standard
                      - strict
                  allow:
                    description: Senders never marked as junk by the junk filter
                    type: array
                    items:
                      type: string
                  block:
                    description: Senders always marked as junk
                    type: array
                    items:
                      type: string
                required:
                  - level
                  - effectiveLevel
                  - allow
                  - block
        '400':
          description: Response for status 400
          content:
            application/json:
              schema:
                type: object
                properties:
                  error:
                    type: string
                required:
                  - error
        '401':
          description: Response for status 401
          content:
            application/json:
              schema:
                type: object
                properties:
                  error:
                    type: string
                required:
                  - error
        '403':
          description: Response for status 403
          content:
            application/json:
              schema:
                type: object
                properties:
                  error:
                    type: string
                required:
                  - error
        '404':
          description: Response for status 404
          content:
            application/json:
              schema:
                type: object
                properties:
                  error:
                    type: string
                required:
                  - error
        '409':
          description: Response for status 409
          content:
            application/json:
              schema:
                type: object
                properties:
                  error:
                    type: string
                required:
                  - error
components:
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: API Key
      description: >-
        Your Inbound API key. Include it in the Authorization header as: Bearer
        <your-api-key>

````

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