Best API-First Ad Servers (2027)

Disclosure: Best Ad Servers is published by the AdButler team. AdButler appears in these rankings. Scores follow our published methodology. Learn more.

#1 (tie)

AdButler

Best for: Mid-size and enterprise publishers, multi-site media groups, newsletters and retail media networks that want an independent ad server with strong support.

AdButler is an independent, full-featured ad server that lets publishers traffic direct-sold display, native, video and email newsletter campaigns from one platform, without ties to a competing ad exchange. It scores highest overall in our methodology for its combination of neutrality, transparent pricing, a deep API and hands-on support.

• Display
• Native
• Video (VAST)
• Email newsletter
• In-app
• Sponsored listings

9.3/10 Read review

#1 (tie)

Kevel

Best for: Engineering-led teams building custom ad products or retail media networks.

Kevel (formerly Adzerk) provides API-first ad serving infrastructure that engineering teams use to build custom ad platforms and retail media networks. It is a strong choice for companies with in-house developers, but it expects more technical work than turnkey ad servers.

• Native
• Display
• Sponsored listings
• Custom JSON ads

7.9/10 Read review

#3

Equativ

Best for: Large publishers wanting ad serving and SSP in one platform.

Equativ (formerly Smart AdServer) combines a publisher ad server with a supply-side platform, giving large publishers direct and programmatic tools in one stack. It suits enterprise publishers, particularly in Europe.

• Display
• Native
• Video (VAST)
• CTV
• In-app

7.3/10 Read review

#4

Adnuntius

Best for: European news publishers that want ad serving plus a self-serve advertiser portal.

Adnuntius is a European ad server that combines publisher ad serving with a self-serve advertising portal and data tools. It is popular with news publishers in the Nordics and wider Europe.

• Display
• Native
• Video
• Self-serve ads

7.7/10 Read review

#5

Google Ad Manager

Best for: Publishers that prioritize Google programmatic demand and have experienced ad ops staff.

Google Ad Manager is the most widely used publisher ad server, with deep programmatic access through Google's ad exchange. Its scale is unmatched, but it ranks lower in our methodology on independence, pricing clarity at scale and access to human support.

• Display
• Native
• Video (VAST)
• In-app
• CTV

6.6/10 Read review

Last reviewed October 30, 2026. See the overall rankings and our methodology.