> ## Documentation Index > Fetch the complete documentation index at: https://docs.stardex.com/llms.txt > Use this file to discover all available pages before exploring further. # Update campaign step > Change only the fields you send. Type, subject, body and `send_after_days` are copied when someone is enrolled, so edits reach people enrolled afterwards; changing `type` keeps the body. Sending window, timezone, signature and `block_until_task_complete` are read when each step runs, so they also apply to people already enrolled; `applies_to_existing_enrollments` lists which of your changes do. Changing the first email subject also updates the `Re:` subject of later email steps. Needs `campaigns:write`. ## OpenAPI ````yaml /api-reference/openapi-v1.json patch /v1/campaigns/{id}/steps/{step_id} openapi: 3.1.0 info: title: Stardex API (v1) version: 1.0.0 description: >- Stardex ATS API — manage candidates, jobs, companies, and recruiting workflows. servers: - url: https://api.stardex.ai description: Production API server security: - bearerAuth: [] tags: - name: Persons description: Manage person records — contacts, work history, and custom fields. - name: Jobs description: Manage job postings — pipeline stages, team members, and custom fields. - name: Candidates description: Manage candidate records and pipeline stage transitions. - name: Companies description: Browse and retrieve company records. - name: Lists description: Create, search, and retrieve saved person and company lists. - name: Person Activities description: Create and manage activity records (notes, emails, meetings) for persons. - name: Team Members description: List team members for use in search filters and assignments. - name: Custom Fields description: Retrieve custom field definitions and tag options for search filters. - name: Campaigns description: >- Create and edit email campaigns, enroll people through enrollment batches, and manage who is enrolled. paths: /v1/campaigns/{id}/steps/{step_id}: patch: tags: - Campaigns summary: Update campaign step description: >- Change only the fields you send. Type, subject, body and `send_after_days` are copied when someone is enrolled, so edits reach people enrolled afterwards; changing `type` keeps the body. Sending window, timezone, signature and `block_until_task_complete` are read when each step runs, so they also apply to people already enrolled; `applies_to_existing_enrollments` lists which of your changes do. Changing the first email subject also updates the `Re:` subject of later email steps. Needs `campaigns:write`. operationId: updateCampaignStep parameters: - schema: type: string format: uuid description: Campaign ID. required: true description: Campaign ID. name: id in: path - schema: type: string format: uuid description: Step ID. required: true description: Step ID. name: step_id in: path requestBody: content: application/json: schema: $ref: '#/components/schemas/CampaignStepUpdateRequest' example: time_window_start: '08:00' responses: '200': description: Step updated content: application/json: schema: $ref: '#/components/schemas/CampaignStepUpdateResponse' example: success: true data: step: id: 5b0f3c8e-2a71-4d0e-9a51-6f0c2d7e1a43 order: 1 type: email send_after_days: 0 subject: '{{search_name}} role at {{search_client}}' body_html: >-
Hi {{first_name}},

{{ai:opening_line}} I'm hiring a {{search_name}} at {{search_client}}. {{personalization_line}}

You can see the role here. Open to a chat?

{{sender_first_name}}
timezone: Europe/London time_window_start: '08:00' time_window_end: '17:00' include_signature: true block_until_task_complete: false ai_variables: - name: opening_line description: >- One sentence on the most relevant thing they have built or led recently. attachments: - file_name: Monzo backend engineering role.pdf content_type: application/pdf size_bytes: 184320 created_at: '2026-10-13T10:15:00.000Z' updated_at: '2026-10-14T08:30:00.000Z' applies_to_existing_enrollments: - time_window_start '400': description: Validation error content: application/json: schema: type: object properties: success: type: boolean enum: - false description: Always false for error responses. error: type: object properties: code: type: string description: >- Machine-readable error code (e.g. "VALIDATION_ERROR", "NOT_FOUND"). message: type: string description: Human-readable error description. details: type: object additionalProperties: {} description: >- Extra facts about the error when they help you fix it, such as a limit and when it resets. required: - code - message required: - success - error '403': description: No access to campaigns, or the API key lacks the permission content: application/json: schema: type: object properties: success: type: boolean enum: - false description: Always false for error responses. error: type: object properties: code: type: string description: >- Machine-readable error code (e.g. "VALIDATION_ERROR", "NOT_FOUND"). message: type: string description: Human-readable error description. details: type: object additionalProperties: {} description: >- Extra facts about the error when they help you fix it, such as a limit and when it resets. required: - code - message required: - success - error '404': description: Resource not found content: application/json: schema: type: object properties: success: type: boolean enum: - false description: Always false for error responses. error: type: object properties: code: type: string description: >- Machine-readable error code (e.g. "VALIDATION_ERROR", "NOT_FOUND"). message: type: string description: Human-readable error description. details: type: object additionalProperties: {} description: >- Extra facts about the error when they help you fix it, such as a limit and when it resets. required: - code - message required: - success - error '500': description: Internal server error content: application/json: schema: type: object properties: success: type: boolean enum: - false description: Always false for error responses. error: type: object properties: code: type: string description: >- Machine-readable error code (e.g. "VALIDATION_ERROR", "NOT_FOUND"). message: type: string description: Human-readable error description. details: type: object additionalProperties: {} description: >- Extra facts about the error when they help you fix it, such as a limit and when it resets. required: - code - message required: - success - error components: schemas: CampaignStepUpdateRequest: type: object properties: type: type: string enum: - email - manual - text - linkedin_message - linkedin_connection - call description: >- Change the step type. The body is kept; people already enrolled keep the type they were enrolled with. send_after_days: type: integer minimum: 0 maximum: 365 description: >- Days to wait after the previous step (or after enrollment, for the first step). subject: type: - string - 'null' maxLength: 998 description: >- Email subject, or the InMail subject for LinkedIn message steps. Only the first email step has its own subject: later email steps always use "Re: " so they land in the same thread (a "Re:" on the first email is removed). Editing a later email's subject is rejected. Can use {{variables}}. body_html: type: string maxLength: 100000 description: >- Step body as HTML (paragraphs, headings, line breaks, bold, italic, underline, strikethrough, highlight, links, lists and images). Each

is followed by an empty line, as in the campaign builder; use
for a line break without a gap. Images need a public https URL and are shown as their own block. Can use {{variables}}, including inside link URLs. For non-email steps this is the task or message text; LinkedIn connection notes are limited to 300 characters. timezone: type: - string - 'null' description: >- IANA timezone for the sending window, for example Europe/London. Defaults to the timezone of the campaign owner's first connected mailbox. Without one, the step sends in New York business hours (America/New_York). time_window_start: type: - string - 'null' pattern: ^([01]\d|2[0-3]):[0-5]\d$ description: >- Start of the sending window for email steps, in 24-hour HH:MM. Left empty, the step sends between 09:00 and 17:00 in its timezone. time_window_end: type: - string - 'null' pattern: ^([01]\d|2[0-3]):[0-5]\d$ description: >- End of the sending window for email steps, in 24-hour HH:MM. Must differ from time_window_start. include_signature: type: boolean description: Add the sender's email signature to this email step. block_until_task_complete: type: boolean description: >- For task steps (not emails): hold the rest of the campaign until this task is marked complete. Turning it off releases anyone already waiting on the step. ai_variables: type: array items: type: object properties: name: type: string minLength: 1 maxLength: 64 description: >- The name used in the template, without the ai: prefix. {{ai:opening_line}} has the name opening_line. description: type: string minLength: 1 maxLength: 1000 description: >- What the AI should write for each person, for example "One sentence on their most relevant recent work". The value is inserted exactly as written, so use the variable only where that text fits: a sentence on its own, never mid-sentence. required: - name - description maxItems: 20 description: >- A description for every {{ai:name}} used in this step. Descriptions for names not used in the step are ignored. CampaignStepUpdateResponse: type: object properties: success: type: boolean enum: - true data: type: object properties: step: $ref: '#/components/schemas/CampaignStep' applies_to_existing_enrollments: type: array items: type: string description: >- Changed fields that also apply to people already enrolled. Subject, body and timing changes only apply to people enrolled after this edit. required: - step - applies_to_existing_enrollments required: - success - data CampaignStep: type: object properties: id: type: string format: uuid order: type: integer description: 1-based position in the campaign. type: type: string enum: - email - manual - text - linkedin_message - linkedin_connection - call send_after_days: type: integer subject: type: - string - 'null' body_html: type: string timezone: type: - string - 'null' time_window_start: type: - string - 'null' description: >- HH:MM. null means the default sending hours, 09:00–17:00 in the step's timezone. time_window_end: type: - string - 'null' description: >- HH:MM. null means the default sending hours, 09:00–17:00 in the step's timezone. include_signature: type: boolean block_until_task_complete: type: boolean ai_variables: type: array items: type: object properties: name: type: string minLength: 1 maxLength: 64 description: >- The name used in the template, without the ai: prefix. {{ai:opening_line}} has the name opening_line. description: type: string minLength: 1 maxLength: 1000 description: >- What the AI should write for each person, for example "One sentence on their most relevant recent work". The value is inserted exactly as written, so use the variable only where that text fits: a sentence on its own, never mid-sentence. required: - name - description attachments: type: array items: type: object properties: file_name: type: string content_type: type: - string - 'null' size_bytes: type: integer required: - file_name - content_type - size_bytes description: >- Files sent with this step, added in the campaign builder. Attachments cannot be added through the API. created_at: type: string updated_at: type: - string - 'null' required: - id - order - type - send_after_days - subject - body_html - timezone - time_window_start - time_window_end - include_signature - block_until_task_complete - ai_variables - attachments - created_at - updated_at securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT description: >- Authenticate with a Bearer token: API key, OAuth token, or session token. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.