NioLeads

About NioLeads

NioLeads is an API that finds and verifies business email addresses. Its email finder endpoint accepts a person's first name, last name, and a company domain or name, returning a found email address and a status message; a verified match consumes one finder credit. A separate endpoint retrieves the account's current credit balance without consuming credits.

Access requires an API key generated from the Integration page, sent as a Bearer token in the Authorization header. Endpoints return JSON and support a concurrent rate limit of 300 simultaneous requests unless otherwise specified, with standard HTTP error codes (400, 401, 404, 429, 500, 503) for invalid requests, authentication failures, missing data, rate limiting, and server issues.

The API is intended for developers integrating email discovery and verification into their own applications, such as sales or outreach tools that need to resolve a contact's business email from their name and employer.

Key features

• Find business email addresses from a person's name and company domain
• REST API authenticated via bearer API key
• Check current API credit balance
• Concurrent rate limit of 300 simultaneous requests per endpoint
• Uses one finder credit per verified email found

Frequently asked questions