Companies
3,806 companies in the AdTech ecosystem
Hivestack
AcquiredProgrammatic Digital Out-of-Home (DOOH) Advertising
Hivestack is a leading technology company specializing in programmatic digital out-of-home (DOOH) advertising, operating as a comprehensive supply-side platform (SSP) that bridges the gap between traditional outdoor advertising and modern digital advertising ecosystems. The company has developed an integrated technology stack encompassing both supply-side and demand-side platforms, along with a specialized ad server designed exclusively for DOOH environments. This end-to-end solution enables ...
Hogarth Worldwide
RebrandedContent Production & Adaptation
Hogarth Worldwide is WPP's content production powerhouse — 10,000+ staff. Acquired by WPP 2008. Provides scaled production + adaptation services across video, digital, print. **Note: WPP announced January 2026 that Hogarth Worldwide is being retired and folded into a new "WPP Production" unit launching February 23, 2026.**
Holoxica
Advanced Display Technology / Holographic Visualization / Medical Technology
Holoxica is a pioneering technology company specializing in advanced holographic and volumetric display systems that enable true three-dimensional visualization without requiring specialized eyewear or virtual reality headsets. The company has developed proprietary optical engineering, photonics expertise, and computational imaging algorithms to create holographic displays that preserve natural depth perception, parallax effects, and spatial relationships critical for accurate interpretation ...
Home Depot Orange Apron Media
Retail Media
Home Depot's retail media network offering advertising solutions to brands and suppliers across its digital and in-store properties.
HomeAdvisor
RebrandedHome Services Marketplace / Lead Generation
HomeAdvisor is a digital marketplace connecting homeowners with local home service professionals, using pay-per-lead advertising to monetize contractor connections.
HookLogic
RebrandedRetail Media / Commerce Media
HookLogic was an early commerce-media platform acquired by Criteo in November 2016 for $250M. Pioneer of retail-media sponsored-product ads on retailer.com properties. Brand retired post-acquisition; tech became the foundation of what's now Criteo Retail Media Platform (RMP).
Hootsuite
Social Media Management & Marketing Technology
Hootsuite is a leading social media management platform that helps organizations and individuals manage their social media presence across multiple platforms, including Twitter, Facebook, LinkedIn, and Instagram.
Hopper
Travel Technology
Hopper is a travel booking app that uses AI and predictive analytics to help users find and book flights, hotels, and rental cars at optimal prices.
HOQU
DefunctAffiliate Marketing / Blockchain
HOQU was a blockchain-based affiliate marketing platform that aimed to create a decentralized performance marketing ecosystem using smart contracts.
Horizon Media
Media Agency / Media Buying
Horizon Media is one of the largest independent media agencies in the United States, providing media planning, buying, and marketing services across all channels.
Hotels.com
Online Travel Agency (OTA) / Travel Commerce
Hotels.com is a leading online travel agency specializing in hotel bookings and accommodation reservations worldwide, operating as part of Expedia Group's portfolio of travel brands.
Hotjar
AcquiredBehavior Analytics / Conversion Rate Optimization
Hotjar is a behavior analytics platform that helps product teams and marketers understand how users interact with their websites through heatmaps, session recordings, and feedback tools. Acquired by Contentsquare in 2021, it continues to operate as a distinct brand.
Huawei
Mobile Advertising Platform
Huawei is a multinational technology company that specializes in telecommunications equipment, consumer electronics, and enterprise solutions. It is one of the largest telecommunications equipment manufacturers in the world.
HubSpot
CRM & Marketing Automation
HubSpot is a leading CRM and inbound marketing platform that helps businesses attract, engage, and delight customers through integrated marketing, sales, and service tools.
HubSpot Email Marketing
Email Marketing & Marketing Automation
Email marketing platform within HubSpot's comprehensive CRM and marketing automation suite, offering tools for creating, sending, and analyzing email campaigns.
Huge
Digital Agency Services
Huge is a global digital agency specializing in design, technology, and marketing services for major brands, operating as a subsidiary of IPG since 2013.
Hugging Face
Hugging Face is an AI platform and community that provides tools, models, and infrastructure for building, training, and deploying machine learning models, particularly focused on natural language processing and generative AI.
Hull
AcquiredCustomer Data Platform (CDP)
Hull.io was a customer data platform (CDP) that unified user data across tools and teams — acquired by MessageBird (now Bird) in March 2021 and subsequently absorbed into its omnichannel communications platform.
Hulu
AcquiredConnected TV (CTV) / Streaming Advertising
Premium streaming service offering on-demand TV shows, movies, and live TV with ad-supported and ad-free subscription tiers.
Hulu + Live TV
Connected TV (CTV) Advertising
Live TV streaming service combining Hulu's on-demand library with 95+ live channels, offering a cable alternative with integrated advertising opportunities.
Hulu Ads
Connected TV (CTV) / Streaming Advertising
Hulu's advertising platform that enables brands to reach streaming audiences through premium video advertising across Hulu's on-demand and live TV services.
HUMAN Security
Ad Fraud & Bot Detection / Cybersecurity
HUMAN Security (formerly White Ops) protects digital advertising from bot attacks, ad fraud, and account takeover. Their platform verifies the humanity of online interactions and secures the advertising ecosystem.
Humanz
Influencer Marketing Technology
Humanz is an AI-powered influencer marketing platform that connects brands with creators for data-driven campaigns. It leverages advanced algorithms to identify suitable influencers, manage campaign logistics, and measure ROI, optimizing the entire influencer marketing process. The platform aims to make influencer marketing more efficient, transparent, and effective for businesses of all sizes.
HUNTER
Public Relations / Integrated Marketing Communications
Consumer PR firm, NYC. Food, beverage, beauty, lifestyle. Joined Stagwell via 2021 MDC merger.