smartlead-api

Send a POST request to /campaigns/{id}/leads with your API key as a query parameter and a body containing a lead_list array. Each lead includes email, first_name, last_name, company_name, and optional custom_fields, batched up to 100 leads per request.

Smartlead uses query parameter authentication by appending ?api_key={SMARTLEAD_API_KEY} to every request against the base URL https://server.smartlead.ai/api/v1. Sub-clients add a client_id parameter, while custom API key clients use their own key directly.

The standard plan allows 2,000 requests per minute and higher plans allow 3,000 per minute. Retry on 429 and 5xx responses with exponential backoff, and use concurrency limiters like p-limit or PQueue set to 8-15 for bulk operations.

Include a seq_variants array inside each sequence object when posting to /campaigns/{id}/sequences. Each variant has a variant_label, subject, and email_body. Do not include a distribution field because Smartlead splits traffic evenly automatically.

The /email-accounts endpoint paginates at 100 accounts per page, so accounts with thousands of inboxes require many requests and can take over 30 seconds to fully walk. Cache the full list in memory or a local JSON file and refresh periodically.