The Best SSP Platforms in 2025

Selecting the right Supply-Side Platform (SSP) is a critical decision for businesses aiming to maximize their programmatic advertising efficiency. With countless platforms offering varying capabilities, the process of narrowing down options can be complex. SSPs act as the backbone of programmatic advertising, enabling publishers to manage, sell, and optimize their ad inventory while ensuring precise targeting and maximizing revenue. 

However, not all SSPs are created equal—differences in technology, transparency, and integration options can have a profound impact on performance. This article highlights key SSP platforms known for delivering robust solutions, exceptional performance metrics, and advanced features tailored to meet the demands of modern programmatic ecosystems. 

For businesses seeking smarter advertising partnerships, understanding what sets these platforms apart is the first step toward better results.

What are SSP Platforms?

SSP platforms, or supply-side platforms, are software that enables publishers to sell, manage, and optimize their ad inventory while maximizing revenue. These platforms provide a centralized interface for publishers to connect with multiple demand sources, including ad exchanges, demand-side platforms (DSPs), and ad networks.

By using an SSP, publishers gain access to a wide range of advertisers and can automate the process of selling their ad space. SSPs use advanced algorithms and real-time bidding technology to ensure that publishers receive the highest possible price for their inventory.

SSPs also offer valuable insights into audience data, allowing publishers to better understand their users and adjust their ad inventory accordingly. This data can help publishers improve targeting, increase ad relevance, and ultimately drive higher revenue.

Top SSP Platforms for Publishers in 2025

As a publisher, choosing the right SSP platform is key to maximizing your ad revenue potential. Here are some of the top SSP platforms to consider in 2025:

1. OpenX

OpenX is one of the leading independent supply-side platforms (SSPs), offering real-time ad inventory monetization for publishers and media owners. With a strong emphasis on transparency, efficiency, and premium inventory, OpenX provides access to a global marketplace of demand partners, including DSPs, agencies, and direct advertisers. 

The platform’s cloud-based infrastructure ensures high-speed transactions and low latency, making it a preferred choice for premium publishers looking to maximize ad revenue.

Why Sell Ad Space Through OpenX?

OpenX offers a highly efficient programmatic marketplace, allowing publishers to connect with top-tier advertisers and achieve higher CPMs through real-time bidding (RTB). Its machine learning-powered yield optimization ensures that publishers earn the maximum possible revenue from every impression. 

Additionally, OpenX prioritizes brand safety and fraud prevention, leveraging strict quality controls and compliance with industry standards. The platform supports multiple ad formats, including CTV, OTT, display, video, and mobile, enabling publishers to monetize diverse content effectively.

Who is OpenX Best For?

OpenX is ideal for premium publishers, media networks, and app developers looking to maximize ad revenue while maintaining control over their inventory. It’s particularly well-suited for CTV and video content owners, as well as news and entertainment publishers that require high fill rates, premium demand, and sophisticated reporting tools.

2. Google Ad Manager

Google Ad Manager is a powerful ad monetization and inventory management platform, enabling publishers to sell ad space programmatically or via direct deals. With its deep integration into Google’s advertising ecosystem, Ad Manager provides access to Google’s extensive demand pool, including Google Ads, Display & Video 360 (DV360), and third-party DSPs.

Why Sell Ad Space Through Google Ad Manager?

Google Ad Manager offers seamless access to premium demand, allowing publishers to monetize their inventory through direct deals, private auctions, and open exchanges. The platform’s dynamic allocation feature ensures that ads are automatically optimized for the highest revenue potential. 

With granular reporting, machine learning-based yield optimization, and built-in fraud protection, publishers gain full control over their ad inventory while maximizing revenue. Google Ad Manager also supports multiple ad formats, including video, display, native, and CTV, ensuring a flexible monetization strategy.

Who is Google Ad Manager Best For?

Google Ad Manager is best for large-scale publishers, media networks, and streaming platforms looking for a fully integrated solution with access to Google’s demand ecosystem. It’s particularly valuable for publishers managing complex, multi-channel ad inventory, such as CTV providers, mobile app developers, and enterprise-level websites.

3. Index Exchange

Index Exchange is a global SSP specializing in transparent and efficient programmatic ad sales. Built for high-speed, real-time ad transactions, the platform connects publishers with premium advertisers while maintaining full transparency in pricing and auction dynamics.

Why Sell Ad Space Through Index Exchange?

Index Exchange offers a fully transparent, publisher-first marketplace, ensuring that advertisers compete fairly for premium inventory. With real-time auction capabilities, publishers can achieve higher fill rates and competitive CPMs. 

The platform’s AI-powered demand optimization dynamically matches inventory with the most lucrative buyers, while its direct integrations with leading DSPs and agencies provide publishers with access to brand-safe, high-quality demand. Additionally, Index Exchange is known for its advanced reporting and insights, helping publishers make data-driven decisions to optimize revenue.

Who is Index Exchange Best For?

Index Exchange is ideal for publishers looking for a transparent, high-efficiency SSP with real-time auction control. It’s particularly suited for digital-first media companies, premium video content owners, and programmatic-focused publishers that require flexible, high-performance monetization strategies.

4. Magnite

Magnite is the largest independent SSP, designed specifically for CTV, OTT, video, and display advertising. Formed from the merger of Rubicon Project and Telaria, Magnite specializes in premium video ad inventory monetization, helping publishers, broadcasters, and streaming platforms optimize revenue through programmatic auctions and direct deals.

Why Sell Ad Space Through Magnite?

Magnite provides one of the most robust monetization platforms for premium video and CTV publishers, offering direct access to leading advertisers and agencies. With header bidding technology, private marketplace (PMP) deals, and preferred programmatic auctions, publishers have full control over inventory pricing and demand sources. 

The platform also integrates brand safety and fraud prevention measures, ensuring a secure, high-quality advertising environment. Additionally, Magnite’s strong relationships with major streaming services make it a go-to SSP for OTT and CTV inventory monetization.

Who is Magnite Best For?

Magnite is best for premium video publishers, streaming services, and CTV providers that need a dedicated SSP for high-quality video and OTT inventory. It’s particularly beneficial for broadcasters, AVOD platforms, and digital-first content creators looking for optimized revenue streams in the rapidly growing CTV and programmatic video market.

5. Microsoft Monetize

Microsoft Monetize, the successor to Xandr, is a comprehensive supply-side platform (SSP) designed to help publishers maximize ad revenue through programmatic and direct sales. As part of Microsoft Advertising, it provides access to premium demand sources, including Microsoft’s extensive advertiser network, third-party DSPs, and direct brand partnerships. 

With a focus on AI-driven monetization, transparency, and premium ad inventory, Microsoft Monetize is a leading choice for publishers looking to optimize their digital advertising strategy.

Why Sell Ad Space Through Microsoft Monetize?

Microsoft Monetize offers advanced AI-driven yield optimization, ensuring that publishers achieve higher fill rates and competitive CPMs. The platform provides real-time bidding, private marketplace (PMP) deals, and programmatic guaranteed options, allowing publishers to maximize revenue across display, video, and connected TV (CTV) inventory.

With deep integration into Microsoft’s advertising ecosystem, Monetize provides direct access to premium brands and high-quality demand sources, giving publishers a competitive advantage. 

Additionally, the platform’s data-driven insights and detailed analytics enable publishers to optimize their inventory strategy in real-time. Microsoft also prioritizes brand safety and compliance, ensuring that ads are delivered in secure, high-quality environments.

Who is Microsoft Monetize Best For?

Microsoft Monetize is best suited for premium publishers, streaming services, and CTV/OTT platforms looking for an enterprise-grade SSP with deep AI-driven optimization. It’s particularly valuable for broadcasters, media companies, and digital-first content providers seeking transparent and scalable monetization solutions with access to Microsoft’s premium ad inventory and global demand partnerships.

What to Look for When Choosing an SSP Platform

When selecting an SSP platform, consider these key factors to ensure you make the best choice for your business:

Robust Analytics and Reporting

Look for an SSP that offers customizable reporting based on specific metrics and attributes. This allows you to analyze your ad inventory performance in granular detail, making data-driven decisions to optimize your revenue. Choose a platform with real-time reporting capabilities so you can quickly identify trends and make necessary adjustments.

Variety of Ad Formats and Channels

Opt for an SSP that supports a wide range of ad formats and channels, including display, video, mobile, CTV, and emerging formats like digital audio and DOOH. This ensures you can monetize your inventory across multiple devices and platforms, maximizing your revenue potential. A diverse ad format offering also attracts a broader range of advertisers, increasing competition for your ad space.

Private Marketplace Deals

An SSP with private marketplace (PMP) capabilities allows you to offer your premium inventory to select advertisers at higher CPMs. PMPs provide a more controlled environment, ensuring brand safety and enabling direct relationships with high-quality advertisers. This can lead to increased revenue and better overall ad quality on your site or app.

Header Bidding Capabilities

Choose an SSP that integrates with header bidding wrappers, such as Prebid or Amazon's Transparent Ad Marketplace (TAM). Header bidding allows multiple demand sources to bid on your inventory simultaneously, increasing competition and potentially driving up your CPMs. SSPs with strong header bidding capabilities can help you maximize your revenue by exposing your inventory to a wider range of advertisers.

Are SSPs the Best Option for Your Business?

While SSPs are essential for publishers looking to monetize ad inventory, managing them effectively requires technical expertise, in-depth optimization, and ongoing monitoring. 

Businesses that lack a dedicated programmatic team may find SSPs overly complex, as they require auction management, pricing strategies, and integrations with multiple DSPs to maximize revenue. Without the right strategy, publishers risk undervaluing their inventory or missing high-value demand opportunities.

Instead of navigating this complicated ecosystem alone, working with Strategus provides a fully managed, hands-off approach to programmatic advertising. Strategus simplifies CTV and OTT monetization, handling everything from ad placement and optimization to real-time attribution and retargeting.

With access to premium ad inventory, advanced AI-driven bidding strategies, and cross-device targeting, Strategus ensures that businesses achieve maximum revenue without the hassle of managing an SSP directly.

Whether you’re a publisher looking to increase ad revenue or a brand seeking high-impact placements, Strategus offers seamless execution, in-depth analytics, and customized campaign management. 

Instead of dealing with the complexities of SSPs, let Strategus optimize your programmatic advertising strategy — delivering higher ROI, better audience engagement, and transparent, data-driven results. 

Talk to a Strategus expert today to learn how we can help you scale your CTV and OTT advertising efforts.