If you’ve ever wondered how ads appear on streaming services, news websites, and mobile apps, the answer is DSPs. They’re the engine behind programmatic advertising, and they’re how the majority of digital ad spend flows in 2026.
How a DSP Works
The process happens in milliseconds:
1. A user loads a page or starts a stream. A website, app, or CTV platform has an ad slot to fill.
2. The publisher’s SSP sends a bid request. The supply-side platform broadcasts the available impression to connected ad exchanges, including user data (anonymized), content context, device type, and geographic location.
3. Your DSP evaluates the opportunity. Does this impression match your targeting criteria? Is this user in your target audience? Is the context brand-safe? How much should you bid?
4. The DSP submits a bid. Based on your campaign settings, the DSP bids a CPM (cost per thousand impressions) it calculates will meet your goals.
5. The highest bid wins. The winning ad is served to the user via real-time bidding. The entire auction takes under 100 milliseconds.
This happens billions of times per day across the internet. And it’s why advertisers can reach specific audiences across thousands of publishers without negotiating a single insertion order.
The Major DSPs
The Trade Desk. The largest independent DSP. Strong across CTV, display, video, audio, and digital out-of-home. Premium inventory access. Excellent reporting. Used by most major agencies. Requires a managed service account or agency relationship.
DV360 (Google Display & Video 360). Part of Google Marketing Platform. The largest DSP by total ad spend because it connects to Google’s inventory. Strong YouTube and Google ecosystem integration. Complex interface with a steep learning curve.
Amazon DSP. Access to Amazon’s first-party shopping data for audience targeting. Powerful for ecommerce advertisers. Increasingly strong in CTV through Amazon Freevee and Fire TV. Available as self-service or managed.
StackAdapt. Independent DSP known for strong CTV capabilities, native advertising, and a cleaner self-service interface than DV360. Popular with mid-market agencies. Good contextual targeting.
Basis (formerly Centro). Full programmatic platform with campaign management, reporting, and billing in one system. Strong for agencies managing complex, multi-channel campaigns.
Xandr (Microsoft). Access to Microsoft’s data and inventory including LinkedIn audience targeting. Solid for B2B campaigns.
DSPs and CTV Advertising
DSPs are how CTV and streaming advertising gets bought programmatically. When you see an ad on Hulu, Peacock, or Tubi, a DSP placed it there.
For CTV specifically, the DSP advantages are:
Audience targeting. Go beyond broad demographics. Target by household income, purchase behavior, interests, and geography. For legal advertising, that means targeting households in specific DMAs with specific demographic profiles.
Frequency management. Control how many times a household sees your ad across streaming platforms. Without a DSP, the same viewer might see your ad 30 times on one platform and zero on another.
Cross-device reach. The DSP can target the same household across their CTV, mobile, desktop, and tablet devices. A CTV ad followed by a mobile retargeting ad creates a connected experience.
Real-time optimization. Shift budget toward placements, audiences, and dayparts that perform best. If Tuesday evening CTV impressions produce more website visits than Saturday afternoon, the DSP adjusts automatically.
DSP vs. Walled Gardens
Not all ad buying happens through open DSPs. Walled gardens (Google, Meta, Amazon) operate their own closed ecosystems:
Google Ads handles search, YouTube, and Google Display Network without needing a separate DSP.
Meta Ads Manager handles Facebook and Instagram advertising in a closed system.
Amazon Ads can be used directly or through Amazon DSP for broader reach.
The distinction matters because a DSP gives you access to the open web and CTV inventory that walled gardens don’t. If your entire budget is in Google Search and Meta, you don’t need a DSP. But if you’re running CTV, display retargeting, or cross-channel campaigns, a DSP unlocks inventory you can’t access through walled gardens alone.
Who Needs a DSP
Agencies managing programmatic campaigns for clients. DSPs are the standard tool for media buyers.
Brands spending $10K+/month on digital beyond search and social. At this spend level, the targeting, optimization, and inventory access justify the platform complexity.
CTV advertisers. If you’re buying streaming inventory at scale, you’re doing it through a DSP. The alternative (direct deals with each streaming platform) is slower, less targeted, and harder to optimize.
Multi-channel advertisers. Running display, video, CTV, and native from one platform means unified frequency management, consistent audience targeting, and holistic reporting.
Legal advertisers running programmatic TV or display retargeting. Only 12% of legal ad spend is on streaming. Firms using DSPs to buy CTV inventory in specific DMAs have a structural advantage over firms buying broadcast or relying solely on Google Ads.
Choosing a DSP
For CTV focus: The Trade Desk or StackAdapt. Both have strong streaming inventory and household-level targeting.
For Google ecosystem: DV360. If you’re already deep in Google Analytics, Google Ads, and Campaign Manager, DV360 connects natively.
For ecommerce: Amazon DSP. The first-party purchase data is unmatched for retail audiences.
For simplicity: StackAdapt or Basis. Cleaner interfaces, faster setup, less overhead than The Trade Desk or DV360.
For budget under $10K/month: Consider whether you need a DSP at all. Google Ads and Meta handle most small-budget campaigns effectively. DSPs add value at scale.
The Cost Structure
DSPs don’t charge per click. They charge per impression (CPM) plus platform fees.
Media cost (CPM). What you pay for the actual ad impressions. CTV CPMs run $20-45. Display CPMs run $2-15. Video CPMs run $10-30. These vary by targeting, inventory quality, and competition.
Platform fee. The DSP’s margin, typically 10-20% of media spend. Some DSPs bundle this into the CPM. Others charge it separately.
Data costs. Third-party audience data segments cost $1-5 CPM on top of media. First-party data (your own) is free to use.
Managed service fees. If an agency or trading desk runs the DSP for you, expect 10-15% management fee on top of media and platform costs.
Total effective CPM for a CTV campaign through a DSP: $25-60 depending on targeting and inventory. Compare that against broadcast TV CPMs of $20-35 without the targeting precision, and the value is clear.
DSP Advertising Use Cases
DSPs power multiple advertising channels beyond just display. DSP advertising includes programmatic display retargeting, video, CTV, and audio. For legal advertisers specifically, DSPs unlock access to programmatic platforms that reach prospects across multiple channels with unified frequency management and budget optimization.
Attribution Through DSPs
Most DSPs offer basic conversion tracking: view-through and click-through attribution. But connecting DSP data to your marketing attribution system requires integration.
The ideal setup: DSP impression data flows into your attribution platform alongside call tracking data, Google Ads conversions, and CRM outcomes. This gives you the full picture of how programmatic impressions contribute to actual business results, not just clicks and impressions.
Want to see how programmatic and CTV advertising can work for your business? Request your free audit and we’ll analyze your market opportunity.