Developer API

A cold email API for campaigns, leads and events.

A REST API for campaigns and leads, webhooks for every event, and an MCP server for AI assistants.

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curl · POST · /api/v1/automation/campaigns/123/leads
# Add a lead to a campaign
curl -X POST \
  https://api.fuzegenai.com/api/v1/automation/campaigns/123/leads \
  -H "Authorization: Bearer $FUZEGENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "leads": [
      {
        "email": "dana@halden.example",
        "name": "Dana Whitfield",
        "company": "Halden Logistics",
        "position": "VP Operations"
      }
    ]
  }'
# GET /api/v1/automation/me
{
  "organizationId": 42,
  "apiKey": {
    "id": 7,
    "name": "Production backend",
    "scopes": ["read"],
    "expiresAt": "2026-12-19T00:00:00.000Z"
  }
}

A REST API for the work you automate.

Read campaigns, change their status and add leads from your own code. Every key has a scope and an expiry.

GET/automation/meCheck a key and see its workspace and scopes.
GET/automation/campaignsList campaigns, a page at a time.
GET/automation/campaigns/:idRead one campaign.
GET/automation/campaigns/:id/sequencesRead a campaign's sequence steps.
POST/automation/campaigns/:id/statusStart, pause, complete or archive a campaign.
POST/automation/campaigns/:id/leadsAdd leads to a campaign. Only email is required.
POST/automation/webhook-subscriptionsSubscribe a URL to events.
POST/automation/test-eventSend a test event to your endpoint.

How API keys work.

Create a key in your organization settings, under Developer. Give it a name you will recognise in the audit log, pick a scope (read-only, read and write, or the same two across all resources) and an expiry from 30 days to never. We recommend 90 days.

The full key is shown once. We store only a one-way hash, so nobody can read it back later, us included. Send it as a bearer token to https://api.fuzegenai.com/api/v1. Every key belongs to one workspace, and its requests run as the person who created it, with that person's permissions.

A missing or expired key gets a 401. A key without the scope an endpoint needs gets a 403 that names the missing scope, so you know exactly what to change. To rotate, create a new key, deploy it, then revoke the old one. Revoking takes effect at once.

The API keys and REST API guide has every endpoint with its scope, plus copy-and-paste examples.

Events, pushed to you.

Subscribe a URL and each event is posted as it happens, signed with your secret.

Campaigns
Created, started, paused, completed
Emails
Sent, opened, clicked, bounced, unsubscribed
Replies
Thread created, replied, converted
Leads and deals
Created, status, deal stage, meeting, site visit

What teams build with it.

Leads from your own product. When someone signs up for a trial or requests a quote, your backend posts them to a campaign. Only the email is required; name, company, position, phone, source, notes and tags are optional.

Campaigns that follow the business. Pause a campaign when a launch slips, or mark it complete when a quarter ends, from the same script that runs the rest of your operations.

Results in your own systems. Subscribe to events such as replies, bounces and meetings booked, and write them to a warehouse or a CRM. Each delivery is signed with your secret. If your CRM is not one we import from, this is how it stays current; see CRM integrations.

An assistant that does the clicking. The MCP server lets Claude, Cursor or Claude Code build campaigns and answer threads for you, with sign-in instead of a key. The AI copilot page explains the access levels.

Rate-limit headers

Every response says how many requests you have left.

Scoped keys

Read-only or read and write, each with its own expiry.

Hashed at rest

We keep a one-way hash. A lost key is replaced, never recovered.

Signed webhooks

Each delivery carries an HMAC signature from your secret.

OpenAPI reference

Interactive docs and a raw spec for any client generator.

Zapier, Make and n8n

Prefer no code? The same events trigger your workflows.

MCP server

Connect Claude, Cursor or Claude Code with one click.

Audit trail

Creating or revoking a key is written to the audit log.

Rate limits and errors, spelled out.

Requests are counted per key. Every response carries headers that say what your limit is, how much is left and when it resets. Go over it and you get a 429 with a Retry-After header; wait that many seconds before trying again.

The full interactive reference is served by the API itself at api.fuzegenai.com/docs, with the raw OpenAPI document beside it for any client generator. There are no official SDK packages, so you are never stuck on an old one.

No-code instead? Zapier, Make and n8n receive campaign events through a webhook URL and can call the API back with a key. The automation guide covers all three. The API and webhooks come with the Professional plan and above.

4
Key scopes
From read-only to read and write
5
Keys on Professional
50 on Enterprise
90 days
Recommended expiry
Or 30 days up to never
Pro
Plan needed
Professional and above

Make your first API call today.

API access comes with the Professional plan. Create a key in your organization settings, then call /me.

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Connect one mailbox and watch it get checked and start warming up. The trial is 14 days and needs no credit card.

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What happens next

  1. 1Connect a mailbox with Google or Microsoft.
  2. 2Its DNS is checked and warmup begins.
  3. 3Import your campaigns, or write a sequence.