> ## Documentation Index > Fetch the complete documentation index at: https://docs.fuseai.com/llms.txt > Use this file to discover all available pages before exploring further. # Render the step for a sample lead without saving or sending > Renders this step for one sample contact from the campaign's source lists - {Variable} tokens filled and spintax resolved - and returns the result WITHOUT saving it and without sending anything. Use it to check a manual step's copy, or to see what an AI step will write. `contact` names the lead the preview was rendered against. If the campaign has no contact to render against, the answer is 422 STEP_PREVIEW_UNAVAILABLE. Only the token owner may preview. Rate limit: this endpoint has a tighter cap of 20 requests/minute and 300/day, applied inside the shared campaigns bucket of 30 requests/minute and 1,000/day per token owner (shared by every campaign, scheduled-send, campaign-template and knowledge-hub endpoint). Errors: - `404` `CAMPAIGN_NOT_FOUND` — No campaign with this id exists, it belongs to another account (including a campaign delegated to you or shared by your team's visibility settings), or it has been deleted. - `404` `SEQUENCE_STEP_NOT_FOUND` — No step with this id belongs to this campaign. - `422` `STEP_PREVIEW_UNAVAILABLE` — There is nothing to render this step against: the campaign has no source list or no contact to sample, or generation produced no preview. - `422` `VALIDATION_FAILED` — campaignId or stepId is not a 24-character hex id. - `429` `RATE_LIMITED` — Either this endpoint's own cap (20 requests/minute, 300/day) or the shared campaigns bucket (30/minute, 1,000/day for this token owner, shared by every /business/campaigns, /business/scheduled-sends, /business/campaign-templates and /business/knowledge-hubs call) was exceeded. The RateLimit-* headers on the response describe the shared bucket, so a refusal from this endpoint's own cap can still report requests remaining and carries no Retry-After. - `500` `UNEXPECTED_ERROR` — An unhandled failure; the detail stays in our logs and is never returned. Requires one of the following token scopes: campaigns. ## OpenAPI ````yaml /openapi.json post /business/campaigns/{campaignId}/steps/{stepId}/generate openapi: 3.1.0 info: title: Fuse Business API version: 1.0.0 description: >- External API for lists, campaigns, prospect search and contacts. Authenticate with your API token as HTTP Basic. All paths are under /api/v1. servers: - url: https://api.tryfuse.ai/api/v1 description: Production security: - basicAuth: [] tags: - name: Lists - name: Custom columns - name: Smart columns - name: Exports - name: Campaigns - name: Knowledge hubs - name: Analytics - name: Website intent - name: Account - name: Prospect search - name: Campaign steps - name: Scheduled sends - name: Campaign templates - name: Agents - name: Research - name: Company search - name: Saved searches - name: Folders - name: Contacts paths: /business/campaigns/{campaignId}/steps/{stepId}/generate: post: tags: - Campaign steps summary: Render the step for a sample lead without saving or sending description: >- Renders this step for one sample contact from the campaign's source lists - {Variable} tokens filled and spintax resolved - and returns the result WITHOUT saving it and without sending anything. Use it to check a manual step's copy, or to see what an AI step will write. `contact` names the lead the preview was rendered against. If the campaign has no contact to render against, the answer is 422 STEP_PREVIEW_UNAVAILABLE. Only the token owner may preview. Rate limit: this endpoint has a tighter cap of 20 requests/minute and 300/day, applied inside the shared campaigns bucket of 30 requests/minute and 1,000/day per token owner (shared by every campaign, scheduled-send, campaign-template and knowledge-hub endpoint). Errors: - `404` `CAMPAIGN_NOT_FOUND` — No campaign with this id exists, it belongs to another account (including a campaign delegated to you or shared by your team's visibility settings), or it has been deleted. - `404` `SEQUENCE_STEP_NOT_FOUND` — No step with this id belongs to this campaign. - `422` `STEP_PREVIEW_UNAVAILABLE` — There is nothing to render this step against: the campaign has no source list or no contact to sample, or generation produced no preview. - `422` `VALIDATION_FAILED` — campaignId or stepId is not a 24-character hex id. - `429` `RATE_LIMITED` — Either this endpoint's own cap (20 requests/minute, 300/day) or the shared campaigns bucket (30/minute, 1,000/day for this token owner, shared by every /business/campaigns, /business/scheduled-sends, /business/campaign-templates and /business/knowledge-hubs call) was exceeded. The RateLimit-* headers on the response describe the shared bucket, so a refusal from this endpoint's own cap can still report requests remaining and carries no Retry-After. - `500` `UNEXPECTED_ERROR` — An unhandled failure; the detail stays in our logs and is never returned. Requires one of the following token scopes: campaigns. operationId: generateCampaignStepPreview parameters: - name: campaignId in: path required: true description: >- The campaign's id (24-character hex ObjectId), as returned by POST /business/campaigns or as the campaignId of a GET /business/campaigns row. schema: type: string description: >- The campaign's id (24-character hex ObjectId), as returned by POST /business/campaigns or as the campaignId of a GET /business/campaigns row. - name: stepId in: path required: true description: >- The sequence step's id, as returned by GET /business/campaigns/{campaignId}/steps (24-character hex ObjectId). schema: type: string description: >- The sequence step's id, as returned by GET /business/campaigns/{campaignId}/steps (24-character hex ObjectId). responses: '200': description: Success headers: RateLimit-Limit: schema: type: integer description: Requests permitted in the current window. RateLimit-Remaining: schema: type: integer description: Requests remaining in the current window. RateLimit-Reset: schema: type: integer description: Seconds until the current window resets. content: application/json: schema: type: object properties: stepId: type: string description: The step that was rendered. preview: type: object properties: subject: type: - string - 'null' description: >- Rendered subject; null on a step with no template yet or a channel that carries none. body: type: - string - 'null' description: >- Rendered message body; null on a step with no template yet. channel: type: - string - 'null' type: type: - string - 'null' enum: - manual - ai_generated - ai_reply - null contact: type: object properties: id: type: - string - 'null' name: type: - string - 'null' email: type: - string - 'null' jobTitle: type: - string - 'null' companyName: type: - string - 'null' required: - id - name - email - jobTitle - companyName required: - subject - body - channel - type - contact required: - stepId - preview example: stepId: 6a8dce156dc0b3d9029c22d7 preview: subject: Quick question about BrightPay's finance hiring body: >-

Hi Imogen, saw BrightPay is scaling its finance team. Worth a 15-minute chat next week?

channel: email type: manual contact: id: 237d2bafce67c35eee9f011d name: Imogen Low email: imogen@brightpay.com jobTitle: Software Engineer companyName: BrightPay '400': description: Error content: application/json: schema: $ref: '#/components/schemas/Error' '401': description: Error content: application/json: schema: $ref: '#/components/schemas/Error' '402': description: Error content: application/json: schema: $ref: '#/components/schemas/Error' '403': description: Error content: application/json: schema: $ref: '#/components/schemas/Error' '404': description: Error content: application/json: schema: $ref: '#/components/schemas/Error' '409': description: Error content: application/json: schema: $ref: '#/components/schemas/Error' '422': description: Error content: application/json: schema: $ref: '#/components/schemas/Error' '429': description: Error content: application/json: schema: $ref: '#/components/schemas/Error' '500': description: Error content: application/json: schema: $ref: '#/components/schemas/Error' security: - basicAuth: [] components: schemas: Error: type: object properties: error: type: object properties: code: type: string message: type: string param: type: - string - 'null' doc_url: type: - string - 'null' request_id: type: - string - 'null' required: - code - message required: - error securitySchemes: basicAuth: type: http scheme: basic description: >- Your API token (`af_…`) as the Basic-auth username, with an empty password. ````