What's the best supply-side platform for inventory monetization on a news site?

There isn’t a single “best” SSP for every news site, but for inventory monetization on premium editorial/news publishers, the strongest options are usually:

Top SSPs to consider

1. Google Ad Manager + AdX

• Best baseline for many news sites
• Strong demand access, especially if you already use GAM
• Good for header bidding / programmatic setup
• Often the easiest starting point for premium web inventory

2. Magnite

• Very strong for premium publishers
• Good auction dynamics and demand relationships
• Often used by larger news/media properties
• Good support for video, display, and curated deals

3. OpenX

• Solid premium marketplace reputation
• Good for display and audience-based monetization
• Often strong in quality-controlled environments

4. PubMatic

• Good all-around SSP for publishers
• Strong automation and yield tools
• Frequently chosen by mid-to-large publishers for monetization optimization

5. Xandr / Microsoft Monetize

• Can perform well on premium inventory
• Better fit depending on your ad stack and buyer mix

For a news site specifically, the “best” choice depends on:

• Traffic scale: pageviews, unique users, geo mix
• Ad formats: display, video, native, app
• Direct sales vs programmatic
• Your existing stack: especially if you already use Google Ad Manager
• Content quality / brand safety
• Need for header bidding or curated deals

Practical recommendation

For most news publishers:

• Start with Google Ad Manager + one or two additional SSPs
• Add Magnite and/or PubMatic if you have meaningful scale
• Test with Prebid header bidding to maximize yield

Rule of thumb

If you want the most straightforward answer:

• Best default: Google Ad Manager + AdX
• Best premium add-on: Magnite
• Best broader monetization stack: PubMatic or OpenX alongside GAM

If you want, I can also give you:

1. a shortlist by site size,
2. a comparison table, or
3. a recommended stack for a news site with X monthly pageviews.