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

# Update a theme

> Update a theme's name and/or styles. Style changes cascade to every email using the theme.

When `styles` change, the update cascades to every email using this theme, and `affectedEmailCount` in the response reports how many emails were affected.

Manual style edits made on individual emails are preserved: the cascade only changes properties an email has not overridden. A per-email override is removed only when it becomes identical to the theme's new value, after which that email follows the theme for that property.


## OpenAPI

````yaml /openapi.json post /v1/themes/{themeId}
openapi: 3.1.0
info:
  title: Loops OpenAPI Spec
  description: This is the OpenAPI Spec for the [Loops API](https://loops.so/docs/api).
  version: 1.21.0
servers:
  - url: https://app.loops.so/api
security: []
tags:
  - name: API key
  - name: Audience segments
    description: View audience segments
  - name: Campaigns
    description: Create and manage email campaigns
  - name: Campaign groups
    description: Organize campaigns into groups
  - name: Components
    description: View email components
  - name: Configuration
    description: View configuration settings
  - name: Contacts
    description: Manage contacts in your audience
  - name: Contact properties
    description: Manage contact properties
  - name: Email messages
    description: Manage email message content for campaigns
  - name: Events
    description: Trigger workflows with events
  - name: Event patterns
    description: View workflow event patterns
  - name: Mailing lists
    description: View mailing lists
  - name: Themes
    description: View email themes
  - name: Transactional emails
    description: Create, manage, and send transactional emails
  - name: Transactional groups
    description: Organize transactional emails into groups
  - name: Uploads
    description: Upload image assets
  - name: Workflows
    description: View and mutate workflow graphs
  - name: Workflow nodes
    description: View and mutate workflow nodes
paths:
  /v1/themes/{themeId}:
    parameters:
      - name: themeId
        in: path
        required: true
        description: The ID of the theme.
        schema:
          type: string
    post:
      tags:
        - Themes
      summary: Update a theme
      description: >-
        Update a theme's name and/or styles. When `styles` change, the update
        cascades to every email using this theme, and `affectedEmailCount` in
        the response reports how many emails were affected. Manual style edits
        made on individual emails are preserved: the cascade only changes
        properties an email has not overridden. A per-email override is removed
        only when it becomes identical to the theme's new value, after which
        that email follows the theme for that property.
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/UpdateThemeBody'
      responses:
        '200':
          description: Successful.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/UpdateThemeResponse'
        '400':
          description: Invalid `themeId` or request body.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ThemeFailureResponse'
        '401':
          description: Invalid API key or content API not enabled for this team.
        '404':
          description: Theme not found.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ThemeFailureResponse'
        '405':
          description: Wrong HTTP request method.
      security:
        - apiKey: []
components:
  schemas:
    UpdateThemeBody:
      type: object
      description: At least one of `name` or `styles` must be provided.
      properties:
        name:
          type: string
        styles:
          $ref: '#/components/schemas/ThemeStyles'
    UpdateThemeResponse:
      allOf:
        - $ref: '#/components/schemas/ThemeResponse'
        - type: object
          properties:
            affectedEmailCount:
              type: number
              description: >-
                The number of emails using this theme that are affected by the
                style change. `0` when only the name changed.
          required:
            - affectedEmailCount
    ThemeFailureResponse:
      type: object
      properties:
        message:
          type: string
      required:
        - message
    ThemeStyles:
      type: object
      description: >-
        Flat map of style attributes, matching the attribute names accepted by
        the LMX `<Style />` tag.
      properties:
        backgroundColor:
          type: string
        backgroundXPadding:
          type: number
        backgroundYPadding:
          type: number
        bodyColor:
          type: string
        bodyXPadding:
          type: number
        bodyYPadding:
          type: number
        bodyFontFamily:
          type: string
        bodyFontCategory:
          type: string
        borderColor:
          type: string
        borderWidth:
          type: number
        borderRadius:
          type: number
        buttonBodyColor:
          type: string
        buttonBodyXPadding:
          type: number
        buttonBodyYPadding:
          type: number
        buttonBorderColor:
          type: string
        buttonBorderWidth:
          type: number
        buttonBorderRadius:
          type: number
        buttonTextColor:
          type: string
        buttonTextFormat:
          type: number
        buttonTextFontSize:
          type: number
        dividerColor:
          type: string
        dividerBorderWidth:
          type: number
        textBaseColor:
          type: string
        textBaseFontSize:
          type: number
        textBaseLineHeight:
          type: number
        textBaseLetterSpacing:
          type: number
        textLinkColor:
          type: string
        heading1Color:
          type: string
        heading1FontSize:
          type: number
        heading1LineHeight:
          type: number
        heading1LetterSpacing:
          type: number
        heading2Color:
          type: string
        heading2FontSize:
          type: number
        heading2LineHeight:
          type: number
        heading2LetterSpacing:
          type: number
        heading3Color:
          type: string
        heading3FontSize:
          type: number
        heading3LineHeight:
          type: number
        heading3LetterSpacing:
          type: number
    ThemeResponse:
      type: object
      properties:
        id:
          type: string
          description: The ID of the theme.
        name:
          type: string
          description: The name of the theme.
        styles:
          $ref: '#/components/schemas/ThemeStyles'
        isDefault:
          type: boolean
          description: Whether this theme is the team's default.
        createdAt:
          type: string
          description: ISO 8601 timestamp for when the theme was created.
        updatedAt:
          type: string
          description: ISO 8601 timestamp for when the theme was last updated.
      required:
        - id
        - name
        - styles
        - isDefault
        - createdAt
        - updatedAt
  securitySchemes:
    apiKey:
      type: http
      scheme: bearer

````

## Related topics

- [API Introduction](/docs/api-reference/intro.md)
- [Themes](/docs/cli/themes.md)
- [Get a theme](/docs/api-reference/get-theme.md)
- [List themes](/docs/api-reference/list-themes.md)
- [Create a theme](/docs/api-reference/create-theme.md)