--- title: "What a DSP is and whether you need one | AdBuyMCP" description: "A demand-side platform buys ads across many publishers through one interface and takes a share of spend, about 20% at The Trade Desk. When that fee pays off." url: "https://adbuymcp.com/guides/what-is-a-dsp-and-do-you-need-one" --- [Home](https://adbuymcp.com/) / [Guides](https://adbuymcp.com/guides) / What a DSP is and whether you need one Guide · buying the awkward channels # What a DSP does and when you need one A DSP needs somebody to operate it, and at most volumes that person costs more than the fee. A demand-side platform is software that buys advertising across many publishers through one interface, bidding on individual impressions in real time, and charging a percentage of what you spend through it. The Trade Desk's own filing for 2024 shows revenue of $2,445m on $12,041m of gross spend, a take of about 20.3% by our arithmetic, and Google publishes no fee for DV360. The fee is easy to compare, but the more important question is whether you have somebody whose job is to operate the platform, because a DSP is a trading interface built for traders and an unattended seat tends to buy cheap inventory against a broad audience. [Get my plan and price](https://adbuymcp.com/start) [Book a 30-minute call with the founder](https://adbuymcp.com/contact#book) Free, with no card. We read your homepage, draft who buys from you and show your monthly price before you join the waitlist. Nothing is bought until you've approved the plan and the ads. By [James Rooney](https://adbuymcp.com/about) Updated 29 October 2026 - **The Trade Desk, 2024**: About 20.3% of gross spend - **Reaching publishers**: About half (ISBA, 2020) - **Unattributable spend**: 15% in 2020, 3% in 2023 - **Length**: 5 min read Sources 3 linked and dated On this page [What to remember](https://adbuymcp.com/guides/what-is-a-dsp-and-do-you-need-one#takeaways) [What a DSP does](https://adbuymcp.com/guides/what-is-a-dsp-and-do-you-need-one#what-a-dsp-does) [Platform fees and supply-chain fees](https://adbuymcp.com/guides/what-is-a-dsp-and-do-you-need-one#platform-fees-and-supply-chain-fees) [A DSP needs someone to operate it](https://adbuymcp.com/guides/what-is-a-dsp-and-do-you-need-one#a-dsp-needs-someone-to-operate-it) [What a DSP will not buy you in the UK](https://adbuymcp.com/guides/what-is-a-dsp-and-do-you-need-one#what-a-dsp-will-not-buy-you-in-the-uk) [Limits that apply](https://adbuymcp.com/guides/what-is-a-dsp-and-do-you-need-one#limits) [Where this came from](https://adbuymcp.com/guides/what-is-a-dsp-and-do-you-need-one#sources) [Questions](https://adbuymcp.com/guides/what-is-a-dsp-and-do-you-need-one#questions) Who this is for Marketing leads being told they should have a DSP, and anyone comparing a platform fee without a clear view of what the platform is for. Key points ## Remember these points if you read nothing else These are the points most likely to change your decision, and the full guide follows below. 1. 01 A DSP is a buying interface, not a seller. It owns no inventory and its value is aggregation and optimisation across publishers. 2. 02 Supply-side and exchange fees sit underneath the platform fee. ISBA's 2020 study with PwC found about half of advertiser spend reaching publishers, which is why the working-media percentage matters more than any single rate. 3. 03 DSPs do not cover UK cinema or addressable television, because neither transacts programmatically. 4. 04 At most volumes the person operating a DSP seat costs more than the platform fee, so below the volume that justifies that person, a managed route or a lighter layer is usually cheaper in total. 01 ## What a DSP does A demand-side platform sits on the buyer's side of an automated marketplace. When an impression becomes available (a page loading, a stream starting), the platform decides in a fraction of a second whether to bid on it and how much, based on the audience, the placement and the rules you set. Programmatic buying is that decision made billions of times. The value proposition is aggregation. Rather than negotiating with fifty publishers, you set an audience and a budget once and the platform sources inventory across all of them. That is genuinely useful, and it is why programmatic took the share of digital advertising that it did. A DSP owns no inventory. It buys from supply-side platforms and exchanges, and that explains the fee structure underneath it. - [How programmatic advertising works](https://adbuymcp.com/glossary/programmatic#programmatic-advertising) 02 ## Platform fees and supply-chain fees The platform fee is the number a DSP will quote you. The Trade Desk's annual report for 2024, filed with the SEC, shows revenue of $2,445m on gross spend of $12,041m, which works out at about 20.3%. That is our arithmetic: the filing says the fee is generally a percentage of a client's total spend and does not print the rate. Google publishes no fee for DV360, and the ranges quoted for it and for smaller DSPs come from secondary sources we could not confirm, so they are left out here. Supply-side and exchange fees sit underneath the platform fee and are rarely quoted. ISBA's 2020 study with PwC found that about half of advertiser spend reached publishers, and that 15% could not be attributed to any party at all. Its 2023 follow-up found the unattributable share down to 3%, and the share reaching publishers "risen by 8%". This is why the single most useful question to ask any buying platform is not its rate but its working-media percentage: how much of what you hand over actually buys advertising. If a platform cannot answer that, treat it as a warning sign. Sources: [The Trade Desk, Form 10-K for 2024, filed with the SEC](https://www.sec.gov/Archives/edgar/data/1671933/000167193325000029/ttd-20241231.htm) (statutory filing); [ISBA, Programmatic Supply Chain Transparency Study, executive summary](https://www.isba.org.uk/system/files/media/documents/2020-12/executive-summary-programmatic-supply-chain-transparency-study.pdf) (industry body); [ISBA, Second Programmatic Supply Chain Transparency Study](https://www.isba.org.uk/knowledge/second-programmatic-supply-chain-transparency-study) (industry body). 03 ## A DSP needs someone to operate it A DSP interface is built for a trader. It assumes somebody who understands bid strategies, inventory quality, supply paths and pacing, and who will look at it daily. That person is the actual cost of a DSP seat, and they cost considerably more than the platform fee at most volumes. The common failure is a seat bought on the promise of control and then operated by somebody with four other jobs. An unattended DSP does not fail loudly; it quietly buys cheap inventory against a broad audience and reports impressions, which looks like activity and is not. If you have that person, or an agency providing them, a DSP is likely the right tool. If you do not, the practical options are a managed service, a lighter layer, or buying directly from the two or three sellers that matter to you. 04 ## What a DSP will not buy you in the UK Cinema and addressable television do not transact programmatically in the UK. Cinema is sold quote-based through two sales houses as packages against films whose performance is unknown until they open; addressable television is booked as paperwork against household attributes. Neither has a self-serve API, and no DSP covers them. This matters if your plan is genuinely multi-channel, because it means a DSP is a partial answer by construction: you will be running the awkward half of the plan somewhere else regardless. If a proposal describes cinema or UK addressable television as programmatic inventory, the platform behind it is either mistaken or reselling somebody else's paperwork with a margin on top. Type your company website or work email to see who we think buys from you, how big your market is and what it costs at 3, 5 or 12 times a week. [Get my plan and price](https://adbuymcp.com/start) Free, with no card. Limits ## These limits apply to everything above This guide does not tell you which DSP to buy, and deliberately so: the answer depends on your inventory needs, your existing stack and the volume you can negotiate with, none of which a general guide can see. It also does not claim AdBuyMCP replaces a DSP. AdBuyMCP is built to buy through several of them, no rail has yet spent, and for a buyer with a trading desk and a digital-only channel set, a DSP seat is the simpler and better answer. A 30-minute call with the founder will tell you whether any of these limits matters for your market. [Book a 30-minute call with the founder](https://adbuymcp.com/contact#book) Where this came from ## Every figure above comes from one of these Every figure above links to the page that published it, with the day it was opened. ### Published sources 1. 01 [The Trade Desk, Form 10-K for 2024, filed with the SEC](https://www.sec.gov/Archives/edgar/data/1671933/000167193325000029/ttd-20241231.htm) Statutory filing · opened 24 September 2026 2. 02 [ISBA, Programmatic Supply Chain Transparency Study, executive summary](https://www.isba.org.uk/system/files/media/documents/2020-12/executive-summary-programmatic-supply-chain-transparency-study.pdf) Industry body · dated May 2020 · opened 24 September 2026 3. 03 [ISBA, Second Programmatic Supply Chain Transparency Study](https://www.isba.org.uk/knowledge/second-programmatic-supply-chain-transparency-study) Industry body · dated 18 January 2023 · opened 24 September 2026 Read next ## These pages pick up where this guide stops Each one goes further into a part of this guide. ### [AdBuyMCP vs The Trade Desk](https://adbuymcp.com/compare/the-trade-desk) Compares the two and shows where The Trade Desk is ahead. ### [Take rate](https://adbuymcp.com/glossary/take-rate) What a take rate is and what DSPs typically charge. ### [What a programmatic advertising company does](https://adbuymcp.com/glossary/programmatic#programmatic-advertising-company) The five kinds of business that sell programmatic, and what each one keeps. ### [What a programmatic advertising agency does](https://adbuymcp.com/glossary/programmatic#programmatic-advertising-agency) The other way to get a seat operated, with the published UK fee ranges. ### [What UK awareness advertising costs](https://adbuymcp.com/cost) Sellers' minimums and prices for billboards, streaming TV, podcasts and ChatGPT ads, sourced and dated. The other 19 guides - [Most B2B buyers have vendors in mind before they search](https://adbuymcp.com/guides/uk-media-buying-for-b2b-marketers) - [Why cross-channel frequency capping rarely happens](https://adbuymcp.com/guides/frequency-capping-across-channels) - [Buying UK DOOH without a movement-data licence](https://adbuymcp.com/guides/buying-uk-dooh-without-movement-data) - [How to buy podcast ads in the UK](https://adbuymcp.com/guides/how-to-buy-podcast-ads-in-the-uk) - [The minimum budget for a startup to test TV advertising in the UK](https://adbuymcp.com/guides/minimum-budget-to-test-tv-advertising) - [How to read a media plan](https://adbuymcp.com/guides/how-to-read-a-media-plan) - [How UK addressable TV targeting actually works](https://adbuymcp.com/guides/how-uk-addressable-tv-targeting-works) - [How Sky AdSmart works](https://adbuymcp.com/guides/sky-adsmart-explained) - [How UK cinema advertising is booked](https://adbuymcp.com/guides/how-uk-cinema-advertising-is-booked) - [Choosing between cinema and CTV](https://adbuymcp.com/guides/choosing-between-cinema-and-ctv) - [Designing a geo-lift test that can actually be powered](https://adbuymcp.com/guides/designing-a-geo-lift-test) - [Incrementality testing on a small budget: a worked power table](https://adbuymcp.com/guides/incrementality-testing-on-a-small-budget) - [Why most incrementality tests are invalid](https://adbuymcp.com/guides/why-most-incrementality-tests-are-invalid) - [What a fidelity score measures](https://adbuymcp.com/guides/what-a-fidelity-score-is) - [First-party data in UK media buying](https://adbuymcp.com/guides/first-party-data-in-uk-media-buying) - [What Clearcast and the CAA actually check](https://adbuymcp.com/guides/what-clearcast-and-the-caa-actually-check) - [Running paid media from an AI agent without losing control](https://adbuymcp.com/guides/running-paid-media-from-an-ai-agent) - [MCP for marketers: what the protocol actually changes](https://adbuymcp.com/guides/mcp-for-marketers) - [The ad platforms' own MCP servers, and planning one budget across them](https://adbuymcp.com/guides/ad-platform-mcp-servers-and-cross-channel-planning) Bring your market ## We'll price an awareness plan for your own market. In a 30-minute call with the founder, we work out how big your market is, price 3, 5 and 12 times a week, and talk through how we'd balance the four channels for your market. [Get my plan and price](https://adbuymcp.com/start) [Book a 30-minute call with the founder](https://adbuymcp.com/contact#book) Free, with no card. Talk your market and your plan through with James Rooney, who built AdBuyMCP and wrote its code. ## Questions this guide gets asked ### Is a DSP cheaper than an agency? Usually, if you compare the fees alone. On total cost it depends entirely on who operates the seat: an agency fee includes a person, and a DSP fee does not. So add the cost of whoever runs the DSP before you compare it with the agency fee. ### Do I need a DSP to buy CTV? No. Connected TV can be bought through a DSP, through a specialist performance-CTV platform, directly from some sellers, or through a layer that buys on your behalf. A DSP makes sense for CTV when it is part of a wider programmatic plan you are already running; it makes less sense when CTV is the only programmatic line you have.