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

# Render template content

> Renders unsaved template content (subject, HTML or MJML, and text) with sample data, without persisting anything.



## OpenAPI

````yaml /openapi.json post /templates/render
openapi: 3.1.0
info:
  description: Helo Email API (https://helohq.com)
  version: 1.0.0
  title: Helo API
servers:
  - url: https://api.helohq.com
security: []
tags:
  - name: Activity
    description: >-
      Track and retrieve message activity, including messages, delivery and
      engagement events.
  - name: Broadcasts
    description: Manage and track broadcast email campaigns.
  - name: Channels
    description: Create and manage communication channels for organizing messages.
  - name: Domains
    description: Register, verify, and manage domains for email sending.
  - name: Sending
    description: Send transactional and broadcast emails.
  - name: Statistics
    description: Access activity statistics.
  - name: Templates
    description: Manage templates for sending.
  - name: Webhooks
    description: Create and manage webhooks for event notifications.
paths:
  /templates/render:
    post:
      tags:
        - Templates
      summary: Render template content
      description: >-
        Renders unsaved template content (subject, HTML or MJML, and text) with
        sample data, without persisting anything.
      operationId: Templates_renderDraft
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/RenderDraftRequest'
        required: true
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RenderTemplateResponse'
        '401':
          $ref: '#/components/responses/401'
        '422':
          $ref: '#/components/responses/422'
        '500':
          $ref: '#/components/responses/500'
      security:
        - bearerAuth: []
      x-codeSamples:
        - lang: ruby
          source: |-
            Helo.configure do |config|
              config.api_key = ENV.fetch("HELO_API_KEY")
            end

            render_draft_request = Helo::RenderDraftRequest.new(
              subject: "test-subject",
              html: "test-html",
              mjml: "test-mjml",
              text: "test-text",
              inline_styles: true,
              data: {}
            )
            Helo::Templates.render_draft(render_draft_request)
        - lang: javascript
          source: |-
            import Helo from "@helo-email/sdk";

            const apiKey = process.env.HELO_API_KEY;
            const helo = new Helo(apiKey);

            const result = await helo.templates.renderDraft({
              subject: "test-subject",
              html: "test-html",
              mjml: "test-mjml",
              text: "test-text",
              inlineStyles: true,
              data: {},
            });
        - lang: go
          source: "package main\n\nimport (\n\t\"context\"\n\t\"log\"\n\t\"os\"\n\n\t\"github.com/helo-email/helo-sdk-go\"\n)\n\nfunc main() {\n\tclient := helo.NewHelo(os.Getenv(\"HELO_API_KEY\"))\n\tctx := context.Background()\n\n\tparams := &helo.RenderDraftRequest{\n\t\tSubject: \"test-subject\",\n\t\tHtml: \"test-html\",\n\t\tMjml: \"test-mjml\",\n\t\tText: \"test-text\",\n\t\tInlineStyles: helo.Bool(true),\n\t}\n\tresult, err := client.Templates.RenderDraft(ctx, params)\n\tif err != nil {\n\t\tlog.Fatal(err)\n\t}\n\t_ = result\n}"
        - lang: csharp
          source: >-
            using HeloEmail.Sdk.Templates;


            var renderTemplate = await helo.Templates.RenderDraft(new
            RenderDraftRequest

            {
                Subject = "test-subject",
                Html = "test-html",
                Mjml = "test-mjml",
                Text = "test-text",
                InlineStyles = true,
            });
        - lang: python
          source: |-
            import sdk_helo_email as helo

            client = helo.Helo()  # reads HELO_API_KEY from the environment

            render_template = client.templates.render_draft(
                subject="test-subject",
                html="test-html",
                mjml="test-mjml",
                text="test-text",
                inline_styles=True,
            )
components:
  schemas:
    RenderDraftRequest:
      type: object
      properties:
        subject:
          type: string
          description: Maximum 256 characters.
        html:
          type: string
          description: Maximum 500,000 characters.
        mjml:
          type: string
          description: >-
            Maximum 500,000 characters. The html it compiles to must also be
            within the html limit.
        text:
          type: string
          description: Maximum 100,000 characters.
        inlineStyles:
          type: boolean
          description: >-
            Inline CSS into the HTML, as a send does. Defaults to true, so the
            preview matches what recipients receive.
        data:
          type: object
          additionalProperties: true
          description: Sample data used to interpolate Liquid variables.
      required:
        - subject
      description: |
        Supplying both html and mjml in the same request is rejected.
    RenderTemplateResponse:
      type: object
      properties:
        subject:
          type: string
        html:
          type: string
        text:
          type: string
      required:
        - subject
    ErrorResponse:
      description: Standard error response body.
      type: object
      properties:
        type:
          description: A URI reference identifying the problem type.
          type: string
        title:
          description: Short, human-readable summary of the problem.
          type: string
        instance:
          description: URI reference identifying the specific occurrence of the problem.
          type: string
        status:
          description: HTTP status code.
          type: integer
          format: int32
        code:
          description: Application-specific error code.
          type: string
        detail:
          description: Human-readable explanation of this specific occurrence.
          type: string
        requestId:
          description: Unique request ID, useful for support correlation.
          type: string
        errors:
          description: Field-level validation errors, keyed by field name.
          type: object
          additionalProperties:
            type: array
            items:
              $ref: '#/components/schemas/ValidationError'
    ValidationError:
      description: A single field validation error.
      required:
        - message
      type: object
      properties:
        message:
          description: Description of the validation failure.
          type: string
  responses:
    '401':
      description: Unauthorized
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
    '422':
      description: Validation Failed
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
    '500':
      description: Internal Server Error
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT

````

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