Hunter.io vs Index Exchange
Side-by-side comparison of AI visibility scores, market position, and capabilities
Email finder and domain search tool for B2B prospecting. Paris France, bootstrapped, 4M+ users, finds professional email addresses from company domains for sales and recruitment outreach.
About
Hunter.io is an email finder and domain search tool used by sales, marketing, and recruitment professionals to find professional email addresses for B2B outreach. Founded in 2015 and headquartered in Paris, France, Hunter.io is a bootstrapped company that has grown to over 4 million users without venture capital. Its Domain Search tool finds all email addresses associated with a given company domain, while the Email Finder tool generates a predicted email address for a specific person at a company based on the company's email format.\n\nHunter.io's core tool is its domain search — users input a company domain and receive a list of publicly findable email addresses at that organization along with a confidence score. The email verifier tool checks whether an address is likely deliverable before it is used in an outreach sequence, reducing bounce rates and protecting sender reputation. A Chrome extension enables email discovery directly from LinkedIn profiles and company websites.\n\nHunter.io has built its large user base through a freemium model that provides a limited number of monthly searches at no cost, converting active users to paid plans as their prospecting volumes grow. Its combination of simplicity, accuracy, and free-tier generosity has made it a default first tool for individuals and small teams starting prospecting programs. While it lacks the intent data, firmographic depth, and compliance infrastructure of enterprise B2B data platforms, Hunter.io's focused email finding capability and ease of use have sustained strong growth in the individual and SMB prospecting segment.
$127-176M revenue 2025; 594 employees Dec 2024; Frost & Sullivan 2025 Innovation Award; Header Tag most-used header-bidding tech 2024; programmatic ad market $595B 2024 to $800B 2028; SSP leader
About
Index Exchange is a global programmatic advertising marketplace founded in 2001 in Toronto, Canada, originally as a traditional ad network and reborn as one of the industry's most trusted independent supply-side platforms. The company's core technology provides publishers with a transparent, high-performance programmatic auction infrastructure for selling display, video, and connected TV advertising inventory, with a strong emphasis on data privacy, header bidding innovation, and clean supply chain practices in an industry often criticized for opacity.\n\nIndex Exchange's platform connects thousands of premium publishers with hundreds of demand-side platforms and agency trading desks, facilitating billions of daily ad transactions across web, mobile, and CTV environments. The company's Header Tag technology was ranked the most widely used header-bidding solution in 2024, reflecting its deep integration into the publisher technology stack. Index Exchange differentiates through its commitment to transparency — providing buyers with detailed supply path information and working to reduce the intermediary layers and fraud that inflate costs across programmatic ecosystems.\n\nIndex Exchange generated between $127 million and $176 million in revenue in 2025 and received Frost & Sullivan's 2025 Innovation Award, underscoring its continued product investment in a consolidating industry. As privacy regulations reshape digital advertising and third-party cookie deprecation forces structural changes in targeting and measurement, Index Exchange's clean supply path positioning and publisher-first approach make it a preferred partner for premium publishers navigating a period of significant disruption. Its independence from major buy-side platforms gives it credibility on both sides of the marketplace.
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