Cold Email API for Agencies and Developers

Resource guide — ColdMailCalculator

Developers and agencies can embed cold email ROI forecasting directly into their tools using the Cold Mail Calculator REST API. Send campaign inputs and receive a complete forecast: delivered emails, replies, positive replies, booked calls, closed deals, revenue, profit, ROI multiple, cost per meeting, and a performance grade.

What the API Does

The API accepts a POST request to /api/v1/coldmail/roi with your campaign parameters and returns a structured forecast. Inputs include email volume, delivery rate, reply rate, positive reply rate, booking rate, close rate, deal value, and campaign cost. The response includes every output metric the calculator produces, making it simple to display results in your own UI or pipeline.

Example output fields:

• Delivered — estimated emails reaching the inbox
• Replies — total replies expected
• Positive Replies — qualified or interested responses
• Booked Calls — meetings scheduled
• Closed Deals — expected clients
• Revenue — projected revenue from closed deals
• Profit — revenue minus campaign cost
• ROI Multiple — return on investment expressed as a multiple
• Cost Per Meeting — campaign cost divided by booked meetings
• Performance Grade — A–F risk score based on funnel health

Use Cases

The API is designed for teams that want to integrate ROI forecasting without building the math themselves. Common use cases include:

• Agency dashboards. Show clients projected ROI for proposed campaigns before launch. Replace spreadsheets with a live forecast embedded in your reporting tool.
• SaaS platforms. Embed forecasting inside your outreach or sales engagement tool. Give users a one-click ROI estimate based on their campaign parameters.
• Lead gen platforms. Add a revenue projection layer to lead data. Show buyers the estimated value of a list or segment before they purchase.
• Internal tools. Automate campaign planning across multiple pipelines. Run hundreds of scenarios programmatically to find the optimal volume and rate mix.

Getting Started

Visit the API page to get a free API key. Review the documentation for request format, authentication, rate limits, and example responses. The API follows standard REST conventions and returns JSON. Integration typically takes a few hours for a basic implementation.

1. Go to the API page and generate your key.
2. Read the docs to understand request and response schemas.
3. Build your integration. Use the live playground to test requests before deploying.
4. Display the forecast in your application or dashboard.

Estimates are for planning purposes only. Actual results depend on your specific audience, offer, timing, and market conditions. Always comply with applicable laws and platform terms.