Email Verification API

Verify An Email Address in Real-Time

COSLR’s Email Verification API enables you to verify an email address in real-time to guarantee its accuracy. You can also bulk upload a list of domains to mass verify emails.

Prevent Fake Emails

Ping the verification API in real-time whenever someone registers for your product or service and verify their email.

Verify Bulk Upload Lists

Upload a CSV list of domains. Verify if it’s an email address is a business email or if it’s a temporary email.

Export The Results

Send the API authenticated email data to your CRM or other software via Zapier or download it as a sheet.

Verify Email Addresses on Sign Up

The Verification API is perfect for Sign Up forms. Check for valid emails and prompt the user before proceeding.

Bulk Upload and Verify Lists

Upload CSV lists and clean emails in real-time. Start your prospect outreach with 100% verified emails.

Ensure emails land in your prospect’s inbox!

Business Leads and Prospecting Tools For Everyone!

Sales Reps

Simplify your sales process. Stop wasting time on research and outreach. Focus on closing inbound, qualified leads. Crush your monthly targets and grow your commission!

Lead Generation Providers

Find new leads and convert them into clients. See exactly what your potential clients are looking for and reach them the minute they land on your page.


Find the perfect candidate for a new position. Increase your outreach and fill more roles. COSLR’s outreach tools will help you find candidates anywhere!

Business Development Reps

COSLR will enable you to find the clients that matter to your business. Search for marketing influencers, paying clients, and future co-workers. Crush your quarterly goals!

Founders and CEOs

Search for the contacts that will drive your business forward! New investors, first employees, future engineers, and paying clients. COSLR lets you do more with limited resources

Export to 5,000+ Apps!

Business leads can be exported via Zapier which has more app integrations than any other platform. Connect to the tools you use today. Learn More about Integrations

Start closing more clients NOW!