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POST
/
api
/
v1
/
campaigns
/
{campaign_id}
/
sequences
curl -X POST "https://server.smartlead.ai/api/v1/campaigns/{campaign_id}/sequences?api_key=YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "sequences": [
      {
        "id": null,
        "seq_number": 1,
        "subject": "Hello {{first_name}}",
        "email_body": "<p>Hi {{first_name}},</p><p>I wanted to reach out...</p>",
        "seq_delay_details": {
          "delay_in_days": 0
        }
      },
      {
        "id": null,
        "seq_number": 2,
        "subject": "",
        "email_body": "<p>Just following up on my previous email...</p>",
        "seq_delay_details": {
          "delay_in_days": 3
        }
      }
    ]
  }'

{
  "ok": true,
  "data": [
    {
      "id": 1001,
      "seq_number": 1,
      "subject": "Hello {{first_name}}",
      "email_body": "<p>Hi {{first_name}},</p><p>I wanted to reach out...</p>"
    },
    {
      "id": 1002,
      "seq_number": 2,
      "subject": "Re: Hello {{first_name}}",
      "email_body": "<p>Just following up on my previous email...</p>"
    }
  ]
}
Creates new sequences (id: null) or updates existing ones. Each sequence needs: seq_number, email_body, and delay in days. Cannot modify while campaign is ACTIVE - pause first.

​
Overview

Create new email sequences or update existing ones for a campaign. Sequences define your multi-step email outreach flow. Key Features:
  • Create new sequences by setting id: null
  • Update existing sequences by including their id
  • Configure delays between emails (0-365 days)
  • Add A/B testing variants with seq_variants
  • Subject line optional for follow-ups (uses “Re:” on previous)
Cannot modify sequences while campaign is ACTIVE. Pause campaign first, make changes, then resume.

​
Path Parameters

​
campaign_id
number
required
The campaign ID

​
Query Parameters

​
api_key
string
required
Your SmartLead API key

​
Request Body

​
sequences
array
required
Array of sequence objects
curl -X POST "https://server.smartlead.ai/api/v1/campaigns/{campaign_id}/sequences?api_key=YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "sequences": [
      {
        "id": null,
        "seq_number": 1,
        "subject": "Hello {{first_name}}",
        "email_body": "<p>Hi {{first_name}},</p><p>I wanted to reach out...</p>",
        "seq_delay_details": {
          "delay_in_days": 0
        }
      },
      {
        "id": null,
        "seq_number": 2,
        "subject": "",
        "email_body": "<p>Just following up on my previous email...</p>",
        "seq_delay_details": {
          "delay_in_days": 3
        }
      }
    ]
  }'

​
Response Codes

​
200
Success
Request successful
​
400
Bad Request
Invalid request parameters or malformed request body
​
401
Unauthorized
Invalid or missing API key. Check your authentication.
​
404
Not Found
The requested resource (campaign, lead, email account, etc.) does not exist or you don’t have access to it
​
422
Validation Error
Request validation failed. Check parameter types, required fields, and value constraints.
​
429
Rate Limit Exceeded
Too many requests. Please slow down and retry after the rate limit resets.
​
500
Internal Server Error
Server error occurred. Please try again or contact support if the issue persists.
​
503
Service Unavailable
API is temporarily unavailable or under maintenance. Please try again later.
{
  "ok": true,
  "data": [
    {
      "id": 1001,
      "seq_number": 1,
      "subject": "Hello {{first_name}}",
      "email_body": "<p>Hi {{first_name}},</p><p>I wanted to reach out...</p>"
    },
    {
      "id": 1002,
      "seq_number": 2,
      "subject": "Re: Hello {{first_name}}",
      "email_body": "<p>Just following up on my previous email...</p>"
    }
  ]
}

​
Personalization Variables

Use these in subject and body:
  • {{first_name}}, {{last_name}}
  • {{company_name}}, {{website}}
  • {{location}}, {{linkedin_profile}}
  • Any custom field: {{job_title}}, {{industry}}, etc.

​
Sequence Best Practices

Keep first email under 125 words for best response rates
Wait 3-5 days between follow-ups - don’t be too aggressive
Each email should provide new value, not just “checking in”

​
Implementation Details

Use id:null to create new sequences. Include existing id to update. Cannot modify sequences while campaign is active. Response Format: object