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

# Preview Template Substitution

> Preview template variable substitution without personalization.

This endpoint renders a template with actual lead data but WITHOUT
AI personalization. Useful for previewing what {{variable}} substitutions
will look like before launching a campaign.

Args:
    campaign_id: Campaign ID
    step_index: Step index to preview
    variant_label: Variant label to preview
    lead_row_index: Row index of lead in dataset to use for preview
    current_user: Authenticated user
    campaign_service: Campaign service instance

Returns:
    Preview of subject and body with variables substituted



## OpenAPI

````yaml https://api.bavlio.com/openapi.json post /api/v1/campaigns/{campaign_id}/template-preview
openapi: 3.1.0
info:
  title: Bavlio API
  description: >-
    Outreach automation API — lead enrichment, email campaigns, LinkedIn
    automation, and AI agent. Full docs at https://docs.bavlio.com.
  version: 1.0.0
servers: []
security: []
tags:
  - name: API Keys
    description: >-
      Create, list, and revoke API keys for programmatic access. JWT
      authentication required.
  - name: credits
    description: Credit balance, cost estimates, and transaction history.
  - name: campaigns
    description: Create, manage, launch, and monitor email campaigns.
  - name: campaign-personalization
    description: AI-powered email subject and body personalization for campaigns.
  - name: email-finder
    description: Find and verify email addresses for prospects.
  - name: email-verification
    description: Validate email addresses and prune invalid entries from datasets.
  - name: sender-profiles
    description: Manage sender identity profiles for outreach.
  - name: sender-profile-chat
    description: Interactive chat for building sender profiles.
  - name: templates
    description: Email template CRUD.
  - name: suppression
    description: Do-not-contact suppression list management.
  - name: datasets
    description: Lead dataset listing, download, and updates.
  - name: user-extractions
    description: Uploaded lead file management and processing.
  - name: enrichment-chat
    description: Interactive chat for data enrichment sessions.
  - name: enrichment-processing
    description: Batch lead enrichment processing.
  - name: File Upload (CSV/Excel)
    description: Upload and preview CSV/Excel lead files.
  - name: connected-accounts
    description: LinkedIn account connections via Unipile.
  - name: linkedin-content
    description: LinkedIn post creation, scheduling, and management.
  - name: linkedin-playground
    description: Direct LinkedIn actions (profile lookup, messaging, engagement).
  - name: bavimail-proxy
    description: BaviMail domain, alias, and email management.
  - name: agent
    description: Bavi AI agent chat with SSE streaming.
  - name: notifications
    description: Notification preferences and delivery.
  - name: referral
    description: Referral code management and stats.
  - name: feedback
    description: User feedback submission.
  - name: authentication
    description: JWT token verification and user info.
  - name: Google OAuth
    description: Google OAuth login flow and access tokens.
  - name: Google Sheets OAuth
    description: Google Sheets import and access management.
  - name: stripe
    description: Stripe checkout, billing portal, and subscription status. JWT only.
  - name: users
    description: User quota and usage information.
  - name: Health
    description: Health checks and system status.
  - name: Personalization
    description: Core lead personalization engine.
  - name: Session Management
    description: Enrichment session lifecycle.
  - name: Session Processing
    description: Session data processing.
  - name: webhooks
    description: Inbound webhook handlers (Stripe, BaviMail, Unipile).
paths:
  /api/v1/campaigns/{campaign_id}/template-preview:
    post:
      tags:
        - campaign-personalization
      summary: Preview Template Substitution
      description: >-
        Preview template variable substitution without personalization.


        This endpoint renders a template with actual lead data but WITHOUT

        AI personalization. Useful for previewing what {{variable}}
        substitutions

        will look like before launching a campaign.


        Args:
            campaign_id: Campaign ID
            step_index: Step index to preview
            variant_label: Variant label to preview
            lead_row_index: Row index of lead in dataset to use for preview
            current_user: Authenticated user
            campaign_service: Campaign service instance

        Returns:
            Preview of subject and body with variables substituted
      operationId: >-
        preview_template_substitution_api_v1_campaigns__campaign_id__template_preview_post
      parameters:
        - name: campaign_id
          in: path
          required: true
          schema:
            type: string
            format: uuid
            title: Campaign Id
        - name: step_index
          in: query
          required: true
          schema:
            type: integer
            minimum: 0
            description: Step index to preview
            title: Step Index
          description: Step index to preview
        - name: variant_label
          in: query
          required: true
          schema:
            type: string
            description: Variant label to preview
            title: Variant Label
          description: Variant label to preview
        - name: lead_row_index
          in: query
          required: true
          schema:
            type: integer
            minimum: 0
            description: Lead row index in dataset
            title: Lead Row Index
          description: Lead row index in dataset
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema:
                type: object
                additionalProperties:
                  type: string
                title: >-
                  Response Preview Template Substitution Api V1 Campaigns 
                  Campaign Id  Template Preview Post
        '401':
          description: Unauthorized - Invalid or missing JWT token
        '404':
          description: Campaign or lead not found
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/HTTPValidationError'
      security:
        - HTTPBearer: []
components:
  schemas:
    HTTPValidationError:
      properties:
        detail:
          items:
            $ref: '#/components/schemas/ValidationError'
          type: array
          title: Detail
      type: object
      title: HTTPValidationError
    ValidationError:
      properties:
        loc:
          items:
            anyOf:
              - type: string
              - type: integer
          type: array
          title: Location
        msg:
          type: string
          title: Message
        type:
          type: string
          title: Error Type
      type: object
      required:
        - loc
        - msg
        - type
      title: ValidationError
  securitySchemes:
    HTTPBearer:
      type: http
      scheme: bearer

````