CTV stands for connected TV, an internet-connected television set or streaming device that plays video content without cable or satellite infrastructure. The term covers smart TVs with built-in internet access, streaming devices such as Roku, Amazon Fire TV and Apple TV, and games consoles running streaming apps. In advertising, CTV also describes the transaction itself: video inventory bought and sold programmatically against these devices, using the real-time bidding infrastructure that already powered display and mobile advertising. The category exists because television viewing shifted from scheduled broadcast and cable to on-demand, app-based streaming, and advertisers needed to buy that inventory with the same automation and targeting tools used elsewhere online.

How CTV advertising works

A CTV transaction begins when a streaming app or smart TV operating system requests video advertising to fill a break inside a programme, a pause screen or a home screen tile. The request typically conforms to OpenRTB, the real-time bidding protocol maintained by IAB Tech Lab, and carries a device object identifying the hardware. Under the AdCOM specification, which factors shared objects out of the core protocol, connected TV sits at devicetype value 3, distinct from mobile, desktop or set-top box. Demand-side platforms evaluate the request against targeting criteria and return a bid within milliseconds when price and audience match.

Two delivery mechanisms decide how the winning ad reaches the screen. Client-side insertion streams content and advertisement as separate files stitched together by the app at playback. Server-side ad insertion, abbreviated SSAI, does that stitching earlier, on the publisher's server, producing a more seamless transition but removing the client-side beacons verification vendors rely on elsewhere. That trade-off between playback quality and measurement transparency runs through much of the industry's current CTV debate.

Ad breaks are frequently organised into pods, several ads playing consecutively to mimic a commercial break. Buyers previously could not bid on a specific position within a pod, and publishers could not set different floor prices per slot. OpenRTB 2.6, developed with Index Exchange and released for public comment through February 7, 2022, addressed this with structured, dynamic and hybrid pod types, letting publishers advertise pod identifiers, slot positions and per-second floor pricing in one bid request.

On the sell side, ad servers and supply-side platforms manage inventory: Magnite's SpringServe, merged with the company's supply-side platform technology in April 2025, connects to what Jounce Media's March 2025 report described as 99 percent of US streaming supply, alongside FreeWheel, Google Ad Manager and PubMatic. On the buy side, The Trade Desk, Amazon DSP, Google Display & Video 360 and Viant place the bids. Curated marketplaces, where a supply-side partner pre-assembles inventory and audience data into a single deal, have grown as an alternative to open bidding, illustrated by Walmart Connect's Connect Select, launched April 27, 2026 with Magnite, PubMatic, FreeWheel and Index Exchange as supply partners.

Origin and evolution

Real-time bidding predates CTV as a meaningful category. OpenRTB began as a pilot among demand-side and sell-side platforms in November 2010, became a unified protocol covering mobile, display and video in 2011, and was adopted as an IAB standard as version 2.1 in January 2012. CTV volume stayed too small for years to justify television-specific changes, until streaming adoption accelerated: the US smart TV installed base grew from 89.1 million units in 2015, 45 percent of television households, to 195.5 million units by 2021, 74 percent of households, according to S&P Global Market Intelligence Kagan data compiled in Video Advertising Bureau research.

Streaming platforms followed the audience. Netflix launched an ad-supported tier in November 2022. Amazon defaulted all Prime Video subscriptions to an ad-supported tier in January 2024, becoming the largest premium ad-supported streaming platform at launch, and Disney+ had reached roughly 30 percent of its global subscriber base on its own ad tier by around January 2025, each platform subsequently opening inventory to programmatic demand.

Technical standards evolved alongside that growth. IAB Tech Lab launched the Ad Format Idol initiative on October 22, 2024, to standardise CTV ad formats that had proliferated inconsistently, noting 75 percent of CTV spend was already transacting programmatically. Submissions closed January 22, 2025, having collected more than 100 proposals from over 40 companies, narrowing to six formats including pause, menu and overlay ads. IAB Tech Lab published the resulting guidelines on December 11, 2025, with comment running to January 31, 2026.

Why CTV matters for the marketing community

EMARKETER's December 2025 projections put US CTV ad spend at 20.0 billion dollars, 23 percent of total television spend, in 2022, rising to 38.0 billion dollars, 43 percent, in 2026, with 47.6 billion dollars, 53 percent, projected by 2028. Traditional television spend is projected to contract from 66.6 billion to 43.1 billion dollars over the same period, while combined spend stays close to flat, suggesting a redistribution between formats rather than new money entering television. Comscore's State of Programmatic Report, released January 20, 2026, found CTV budgets had risen three percentage points year over year to 26 percent of average media spend, with more than half of respondents expecting over 60 percent of CTV buys to run programmatically.

Nielsen's Gauge report, published July 2025, found streaming overtook the combined share of broadcast and cable for the first time, reaching 44.8 percent of viewing in May 2025 against a combined 44.2 percent, and the Video Advertising Bureau's twelfth annual streaming report, published April 2026, documented 210 million US ad-supported viewers and a cord-cutting majority among US households. For buyers, CTV combines television's premium viewing environment with digital targeting; for sellers, it monetises content that previously ran only through limited direct sales.

Limitations, criticisms and open disputes

CTV's measurement infrastructure has not kept pace with spending growth. Server-side ad insertion strips out the client-side signals verification vendors use elsewhere to confirm an ad rendered correctly. IAB Europe's April 2026 Guide to Programmatic for CTV stated that CTV measurement is heavily influenced by server-side insertion, recommending cryptographic device attestation as a remedy. IAB Spain's fifth annual CTV study, published May 6, 2026, found 44 percent of professionals lacked confidence in CTV measurement.

That opacity attracts fraud at scale. DoubleVerify's 2026 Global Insights report, published May 7, 2026, found CTV fraud schemes rose 140 percent in the first quarter compared with the same period in 2025, alongside a tenfold rise in fraudulent apps detected. HUMAN Security's disruption of the NewsJunkie scheme, disclosed in mid-2026, uncovered spoofed device, app and IP details at a peak of two billion bid requests daily, undermining the assumption that direct deals carry lower fraud risk than open exchanges.

A more mundane problem is delivery to switched-off screens: DoubleVerify data found more than one in three CTV impressions deliver to a powered-off television, detectable through HDMI-CEC signalling that almost no vendor implements. A Jamloop survey of 120 marketers, released July 9, 2026, found only 33 percent fully trusted platform-reported CTV performance, even as half had raised CTV budgets year over year.

Some criticism targets the metrics rather than fraud. Programmatic director Austin Lake argued in June 2026 that CTV completion rates, often around 98 percent, are structurally guaranteed rather than earned, since CTV ads typically cannot be skipped. Separate research from Gracenote found 86 percent of media planners would move more linear budget into CTV if show-level targeting and reporting were consistently available, a gap the Association of National Advertisers tied to 26.8 billion dollars in global programmatic ad waste, with CTV representing 44 percent of that spend.

Privacy exposure adds a further dispute, particularly around automatic content recognition, or ACR, the technology many smart TV manufacturers use to fingerprint audio or video and match it against a reference database to log viewing. In December 2025, the Texas attorney general sued Hisense, alleging the manufacturer disguised its ACR system as an "Enhanced Viewing Service" during setup, affecting an estimated 1.27 million residents. Separately, the 1988 Video Privacy Protection Act has become the basis for litigation constraining how streaming platforms share individual viewing data. Creative execution lags too: research from Smartly and EMARKETER found 72 percent of marketers reused or only slightly modified creative across social and CTV campaigns.

Disambiguation

CTV describes a device category and, by extension, the inventory sold against it. OTT, over-the-top, describes the delivery method rather than the device: any video transmitted over the open internet, bypassing cable or broadcast. All CTV is OTT, but not all OTT is CTV, since OTT also reaches mobile phones and desktop browsers.

FAST, free ad-supported streaming television, describes a content model: linear-style channels requiring no subscription, monetised entirely through advertising. FAST channels frequently run on CTV devices, but the term refers to the programming model, not the hardware.

vMVPD, a virtual multichannel video programming distributor, is a subscription service carrying licensed cable and broadcast networks over the internet, an application that runs on a CTV device rather than the device category itself.

SSAI, server-side ad insertion, is a technical delivery method widely used within CTV, splicing advertising into the stream before it reaches the device, not a synonym for the category.

Addressable TV refers to household-level targeted advertising delivered through set-top box or cable infrastructure on linear television, a distinct technical lineage from internet-delivered CTV, though the two increasingly appear together under the broader term Advanced TV.

Recent developments

In July 2026, IAB Tech Lab opened a further 30-day comment period on a Redefining Media Types Standard intended to standardise viewing-bucket terminology across planning tools, DSPs and reporting dashboards. Consolidation reshaped the supply side too: Fox's agreement to acquire Roku for 22 billion dollars, reported around June 2026, raised questions about whether a buyer with incentives to route demand through its own channels would alter Roku Exchange's economics. Samsung opened its Smart TV home screens to programmatic buying through The Trade Desk and Google Display & Video 360 the same month, using Magnite's SpringServe as the underlying technology.

Timeline

  • November 2010: OpenRTB begins as a pilot project among demand-side and sell-side platforms
  • February 2011: OpenRTB v1.0 launches as a mobile-focused real-time bidding protocol
  • Later 2011: OpenRTB unified into a single specification covering mobile, display and video
  • January 2012: OpenRTB becomes an IAB standard as version 2.1
  • 2016: OpenRTB 2.5 released
  • Spring 2021 to February 7, 2022: OpenRTB 2.6 developed and opened for public comment, introducing structured, dynamic and hybrid ad pod bidding for CTV
  • November 2022: Netflix launches its ad-supported streaming tier
  • January 2024: Amazon defaults all Prime Video subscriptions to an ad-supported tier
  • June 2024: Roku launches Roku Exchange, its programmatic advertising infrastructure
  • October 22, 2024: IAB Tech Lab launches the Ad Format Idol initiative to standardise CTV ad formats
  • December 11, 2024: IAB Tech Lab announces content taxonomy updates introducing enumerated CTV genre values
  • January 22, 2025: Ad Format Idol submission window closes, having collected more than 100 format proposals from over 40 companies
  • February 15, 2025: Google completes its transition to the OpenRTB protocol
  • April 2025: Magnite merges its SpringServe ad server with its supply-side platform technology
  • December 11, 2025: IAB Tech Lab publishes six standardised CTV ad formats for public comment, running through January 31, 2026
  • April 2026: IAB Europe publishes its Guide to Programmatic for CTV
  • April 27, 2026: Walmart Connect launches Connect Select, a curated CTV marketplace
  • May 7, 2026: DoubleVerify's 2026 Global Insights report documents a 140 percent rise in CTV fraud schemes
  • June 2026: Fox agrees to acquire Roku for 22 billion dollars; Samsung opens Smart TV home screens to programmatic buying
  • July 2026: HUMAN Security discloses disruption of the NewsJunkie fraud scheme; IAB Tech Lab opens comment on the Redefining Media Types Standard

Summary

Who: Advertisers, agencies and demand-side platforms including The Trade Desk, Amazon DSP and Google Display & Video 360 buy CTV inventory; publishers and platforms including Netflix, Disney+, Amazon Prime Video, Roku, Samsung and VIZIO sell it, routed through supply-side platforms and ad servers such as Magnite's SpringServe, FreeWheel and PubMatic; IAB Tech Lab, IAB Europe and national IAB chapters maintain the underlying technical standards.

What: Connected TV, an internet-connected television device or streaming device, and by extension the programmatic video advertising inventory transacted against it using OpenRTB, AdCOM and related IAB Tech Lab specifications.

When: The underlying real-time bidding protocol dates to 2011, but CTV became a major programmatic category only as streaming adoption accelerated through the 2020s, with pod-bidding support arriving via OpenRTB 2.6 in 2021 and 2022, major ad-supported tier launches from Netflix, Disney+ and Amazon between 2022 and 2024, and standardised ad formats published in December 2025.

Where: Primarily the United States, where eMarketer projected 38 billion dollars in CTV ad spend for 2026, though European markets including Spain and France published their own technical standardisation guides in 2026, and adoption is growing in markets including Ukraine, which recorded 115 percent CTV growth in 2025 from a small base.

Why: Television viewing moved from scheduled broadcast and cable to on-demand and app-based streaming, and advertisers needed programmatic infrastructure, comparable to what already existed for display and mobile, to buy that inventory at scale, though measurement transparency, fraud and screen-off delivery remain unresolved problems that lag the pace of budget growth.