RTB Architecture

Dynamic creative optimization in HTML5: build pipelines, IAB specs, rendering and QA

Q: How does clickTag work in an HTML5 ad?

The ad declares a clickTag variable holding the landing page URL and opens it on click. The ad server replaces the value with its own click-tracking URL at serve time. DV360 requires click tags, warns against minifying them and requires the landing page to open in a new tab or window (Google, DV360 Help (https://support.google.com/displayvideo/answer/10261241?hl=en)).

Q: How do I test for Chrome's heavy ad intervention?

Disable chrome://flags/#heavy-ad-privacy-mitigations so Chrome applies the thresholds exactly, then use DevTools CPU and network throttling to mimic slow devices. In production, capture intervention reports through the Reporting API (Chrome for Developers, updated 7 January 2026 (https://developer.chrome.com/docs/web-platform/heavy-ads-intervention)).

Published November 10, 2026 · Last updated November 10, 2026
Next scheduled review: 9 May 2027

By Art Kukharenko, CEO

Dynamic creative optimization (DCO) in HTML5 means one template per ad size, filled at serve time from a data feed by rules. The engineering work is the pipeline around it: templates, feeds, file-weight budgets, IAB Tech Lab specs such as SIMID and Open Measurement, rendering checks in each ad server and automated QA.

Contents

Key facts

The IAB budget for a 300x250 is 150 kB. The IAB New Ad Portfolio sets 150 kB for the initial load and 300 kB for the subload of a medium rectangle, gzipped. It allows at most ten file requests during the initial load (IAB Tech Lab, Fixed Size Ad Specifications, 2017).
Chrome removes heavy ads. It unloads an ad the user has not touched once it uses more than 4 megabytes of network. The same happens above 15 seconds of main-thread time in any 30-second window, or 60 seconds in total (Chrome for Developers, updated 7 January 2026).
DSPs add their own ceilings. Display & Video 360 caps an HTML5 ad at 5 MB of total download, 100 HTTP calls and 25 cookies, and limits animation to 30 seconds (Google, DV360 Help, accessed 9 November 2026).
SIMID 1.2 is in the repository. IAB Tech Lab added a SIMID 1.2 document on 23 July 2026; the last tagged releases are 1.1 (25 January 2022) and 1.0 (28 June 2019) (IAB Tech Lab, SIMID repository).
Open Measurement keeps shipping. The Open Measurement SDK JavaScript clients reached version 1.6.12 on 2 November 2026 (IAB Tech Lab, Open-Measurement-JSClients changelog).
VAST 4.4 is still a draft. The VAST 4.4 text in IAB Tech Lab's repository says "Publication Date TBD"; VAST 4.3 is dated December 2022 (IAB Tech Lab, VAST4.x repository).

Jump to the table

Definition

DCO HTML5 pipeline: the build, data and release process that turns one HTML5 creative template per size into many ad variations by binding template slots to rows of a content feed through targeting rules. It also tests every variation against publisher, platform and browser limits before the ad serves.

Dynamic creative optimization (DCO) as a marketing method, with strategy and examples, is covered in dynamic creative optimization strategies. This page is the engineering view and sits in the RTB architecture hub. It assumes you know what an ad server and a demand-side platform (DSP) do.

How a DCO pipeline works: template, feed, rules, render

A DCO system has four parts. The template is an HTML5 shell with named slots for text, images, prices and links. The feed is a table of content, one row per variation. Rules pick a row for each impression from signals such as location, audience or placement. The renderer fills the slots and shows the ad.

Google's Studio, which serves dynamic creatives through Campaign Manager 360 (CM360), uses the same split. A dynamic creative is "an HTML creative file" that frames the content, plus a Studio profile holding the rules and the mapping between creative elements and content (Google, Studio Help, accessed 9 November 2026). Google states that these dynamic creatives are available for CM360 users and not for Google Ad Manager.

The split matters for testing. A template is code, so it gets code checks once per release. A feed is data, so every update needs data checks, because one long product name can break a layout across thousands of impressions.

Templates: an HTML5 shell that survives every ad server

Build each template as a small, self-contained web page. The IAB's ad portfolio guidance says HTML5 ads "are like mini web pages" and that the number of file requests has a big effect on load performance (IAB Tech Lab, 2017). The same document recommends inline styles, asynchronous scripts inside a sandboxed iframe and no animation while the ad is out of view.

Four rules keep a template portable across ad servers and DSPs:

One package per size. DV360 expects a ZIP of HTML, CSS, JS, image and font files, up to 100 files (Google, DV360 Help).
A readable clickTag. DV360 requires click tags for the landing page and warns, "Don't use a code minifier on the click tag." The landing page must open in a new tab or window.
Polite loading. Load only what the first frame needs before the page's load event. Fetch the rest afterwards, as the LEAN rules require.
No reliance on the host page. The ad runs in a cross-origin iframe in most environments, so it cannot read the publisher's DOM or cookies.

Shared libraries need a decision. The IAB lets publishers exempt named shared libraries from the weight count, up to 50 kB combined in the initial load. Any library a publisher has not named counts in full (IAB Tech Lab, 2017). Bundle a small library rather than gamble on an exemption you have not confirmed.

Feeds and rules: the data contract

A feed is a contract between the people who write content and the template that displays it. Write the contract down: field names, types, maximum lengths, image sizes and the default row. The row below is our illustrative format, not a Google Studio or vendor schema.

{
  "row_id": "sku-48213-uk",
  "is_default": false,
  "active_from": "2026-11-10T00:00:00Z",
  "active_to": "2026-11-30T23:59:59Z",
  "targeting": { "country": "GB", "audience_segment": "returning_visitor", "placement_size": "300x250" },
  "headline": "Winter boots, 30% off",
  "headline_max_chars": 28,
  "price": { "amount": 69.0, "currency": "GBP", "display": "£69" },
  "image": { "url": "https://cdn.example.com/dco/boots-600x500.webp", "width": 600, "height": 500, "max_kb": 45 },
  "cta_text": "Shop now",
  "exit_url": "https://shop.example.com/boots?utm_source=display",
  "reporting_label": "boots_winter_returning"
}

7 of 7 rows

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`is_default`	One row must be marked default. It serves when no rule matches.
`active_from`, `active_to`	Prices and offers expire; the rules engine must not serve stale rows
`targeting`	The signals the rules engine matches; keep keys identical to the ad server's targeting keys
`headline_max_chars`	The template's real limit, tested at build time against every row
`image.width`, `image.height`	Twice the display size for high-density screens, as DV360 recommends for images
`image.max_kb`	Each row's weight counts toward the ad's load budget
`reporting_label`	Lets reports show which variation won without decoding row IDs

`is_default`

Why it exists: One row must be marked default. It serves when no rule matches.

`active_from`, `active_to`

Why it exists: Prices and offers expire; the rules engine must not serve stale rows

`targeting`

Why it exists: The signals the rules engine matches; keep keys identical to the ad server's targeting keys

`headline_max_chars`

Why it exists: The template's real limit, tested at build time against every row

`image.width`, `image.height`

Why it exists: Twice the display size for high-density screens, as DV360 recommends for images

`image.max_kb`

Why it exists: Each row's weight counts toward the ad's load budget

`reporting_label`

Why it exists: Lets reports show which variation won without decoding row IDs

Download JSON

Table by AdSovereign, CC BY 4.0.

Google's QA checklist for Studio shows why the default row matters. If the feed has no default column and no location matches, there is "no eligible content to serve", and CM360 picks another creative in the rotation (Google, Studio Help, accessed 9 November 2026). The same page warns that test IDs may work in preview "however they won't work when the creative is live". It tells teams to replace them, retransform the feed and republish the profile.

File-weight and load limits, side by side

Three bodies set limits on the same ad: the IAB recommends, browsers enforce and platforms reject. Your build budget must satisfy the strictest number at each point.

9 of 9 rows

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Initial load, 300x250	150 kB gzipped	n/a	n/a
Subload, 300x250	300 kB gzipped, after the page `load` event	n/a	n/a
Initial load, 970x250 billboard	250 kB, subload 500 kB	n/a	n/a
Total network	Unlimited after user interaction	Ad unloaded above 4 MB without interaction	5 MB maximum download
File or HTTP requests	10 in the initial load	n/a	100 HTTP calls; 100 files in the ZIP
CPU	30% of average CPU per active ad	15 s of main thread in any 30 s window, or 60 s in total	n/a
Animation	Stop when complete; none while out of view	n/a	30 seconds maximum
Slow networks	30% lighter on 3G or slower	n/a	n/a
Not counted	Ad server, measurement and verification files	All resources of child frames count	n/a

Initial load, 300x250

IAB New Ad Portfolio (2017): 150 kB gzipped
Chrome Heavy Ad Intervention: n/a
DV360 HTML5 display: n/a

Subload, 300x250

IAB New Ad Portfolio (2017): 300 kB gzipped, after the page load event
Chrome Heavy Ad Intervention: n/a
DV360 HTML5 display: n/a

Initial load, 970x250 billboard

IAB New Ad Portfolio (2017): 250 kB, subload 500 kB
Chrome Heavy Ad Intervention: n/a
DV360 HTML5 display: n/a

Total network

IAB New Ad Portfolio (2017): Unlimited after user interaction
Chrome Heavy Ad Intervention: Ad unloaded above 4 MB without interaction
DV360 HTML5 display: 5 MB maximum download

File or HTTP requests

IAB New Ad Portfolio (2017): 10 in the initial load
Chrome Heavy Ad Intervention: n/a
DV360 HTML5 display: 100 HTTP calls; 100 files in the ZIP

CPU

IAB New Ad Portfolio (2017): 30% of average CPU per active ad
Chrome Heavy Ad Intervention: 15 s of main thread in any 30 s window, or 60 s in total
DV360 HTML5 display: n/a

Animation

IAB New Ad Portfolio (2017): Stop when complete; none while out of view
Chrome Heavy Ad Intervention: n/a
DV360 HTML5 display: 30 seconds maximum

Slow networks

IAB New Ad Portfolio (2017): 30% lighter on 3G or slower
Chrome Heavy Ad Intervention: n/a
DV360 HTML5 display: n/a

Not counted

IAB New Ad Portfolio (2017): Ad server, measurement and verification files
Chrome Heavy Ad Intervention: All resources of child frames count
DV360 HTML5 display: n/a

Download JSON

Table by AdSovereign, CC BY 4.0.

Sources: IAB Tech Lab, Fixed Size Ad Specifications, 2017; Chrome for Developers, updated 7 January 2026; Google, DV360 Help, accessed 9 November 2026.

The IAB numbers changed over time. The 2015 display guidelines allowed 200 KB for a 300x250 and 15 file requests, with subload starting one second after domContentLoadedEventEnd (IAB, Display and Mobile Creative Guidelines, last updated 29 September 2015). The 2017 portfolio tightened both and moved the trigger to the window load event. Publishers' own specifications still differ, so the 2015 document's advice stands: check each publisher's requirements.

The file sizes below are an illustrative build, not measurements. The target is the IAB's 150 kB gzipped initial load (IAB Tech Lab, 2017).

10 of 10 rows

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`index.html` with inline CSS	Initial	6 kB
Template script, bundled and minified	Initial	24 kB
Feed row JSON	Initial	2 kB
Product image, 600x500 WebP	Initial	45 kB
Logo SVG	Initial	3 kB
Web font subset	Initial	18 kB
Initial total		98 kB in 6 requests
Animation sprite sheet	Subload	120 kB
Second product image	Subload	45 kB
Subload total		165 kB

`index.html` with inline CSS

Load phase: Initial
Gzipped size (illustrative): 6 kB

Template script, bundled and minified

Load phase: Initial
Gzipped size (illustrative): 24 kB

Feed row JSON

Load phase: Initial
Gzipped size (illustrative): 2 kB

Product image, 600x500 WebP

Load phase: Initial
Gzipped size (illustrative): 45 kB

Logo SVG

Load phase: Initial
Gzipped size (illustrative): 3 kB

Web font subset

Load phase: Initial
Gzipped size (illustrative): 18 kB

Initial total

Load phase
Gzipped size (illustrative): 98 kB in 6 requests

Animation sprite sheet

Load phase: Subload
Gzipped size (illustrative): 120 kB

Second product image

Load phase: Subload
Gzipped size (illustrative): 45 kB

Subload total

Load phase
Gzipped size (illustrative): 165 kB

Download JSON

Table by AdSovereign, CC BY 4.0.

The initial load leaves 52 kB of headroom for a heavier feed row. The subload stays under 300 kB. Note that the feed image counts against the IAB budget, so the max_kb field in the feed is a build-time check, not a suggestion.

Video and CTV: VAST, SIMID and the end of VPAID

Video ads arrive through the Video Ad Serving Template (VAST). For interactivity, the old answer was VPAID, which let ad code run inside the player. Its successor is the Secure Interactive Media Interface Definition (SIMID). The SIMID text says it "is part of a broader effort to replace the older VPAID standard", with Open Measurement taking over verification (IAB Tech Lab, SIMID 1.2).

6 of 6 rows

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Where the ad code runs	In the player's page, with access to its DOM	In a cross-origin iframe, no player DOM access
Who plays the video file	The creative	The player
Communication	Direct function calls	`postMessage` messages
Server-side ad insertion	Not possible	Possible
Verification	Done by the creative	Left to Open Measurement
Resource MIME type	`application/javascript`	`text/html`

Where the ad code runs

VPAID: In the player's page, with access to its DOM
SIMID: In a cross-origin iframe, no player DOM access

Who plays the video file

VPAID: The creative
SIMID: The player

Communication

VPAID: Direct function calls
SIMID: postMessage messages

Server-side ad insertion

VPAID: Not possible
SIMID: Possible

Verification

VPAID: Done by the creative
SIMID: Left to Open Measurement

Resource MIME type

VPAID: application/javascript
SIMID: text/html

Download JSON

Table by AdSovereign, CC BY 4.0.

Source: the comparison table in SIMID 1.2. That separation is why SIMID works with server-side ad insertion (SSAI): the player keeps control of the stream. A VAST response points to the SIMID file with an <InteractiveCreativeFile> element of type text/html and apiFramework="SIMID". The VAST 4.4 draft extends that element to non-linear ads such as pause and squeeze-back units (IAB Tech Lab, VAST 4.4 draft). CTV delivery is covered in SSAI and CTV ad serving.

SIMID 1.2 adds guidance on L-shaped squeeze-back ads, a value of -1 for unknown sizes and a rule that session IDs must be cryptographically secure (SIMID 1.2, section 2.3). Its signalling lags behind. The AdCOM 1.0 list of API frameworks has values for SIMID 1.0 (8) and SIMID 1.1 (9) but none for 1.2 (IAB Tech Lab, AdCOM 1.0). Until a value appears, bid requests can only say "SIMID 1.1". In apps, the MRAID 3.0 framework (value 6) plays the equivalent role for rich display ads.

Measurement: Open Measurement inside the creative

Viewability and verification vendors measure through the Open Measurement SDK (OM SDK). Its JavaScript clients have two parts: a verification client that vendor scripts use, and a session client that integration partners include in ad HTML at build time (IAB Tech Lab, Open-Measurement-JSClients). Version 1.6.12 shipped on 2 November 2026 with no changes from 1.6.11, which fixed stale element positions after resizes (changelog).

The bid stream has to say that OM is available and required. IAB Tech Lab's note on OpenRTB support for OMSDK puts value 7 in the api list of the Banner, Video or Native object. It adds omidpn and omidpv for the integration partner's name and version (IAB Tech Lab, OpenRTB support for OMSDK). The bid then lists 7 in apis, the array that replaced api in OpenRTB 2.6. The fragment below shows a DSP's bid carrying HTML5 markup that requires OMID; values are illustrative.

{
  "id": "auction-7f3a",
  "seatbid": [
    {
      "seat": "buyer-seat-12",
      "bid": [
        {
          "id": "bid-1",
          "impid": "1",
          "price": 2.35,
          "adm": "<div id=\"dco\" data-row=\"sku-48213-uk\"><script src=\"https://cdn.example.com/dco/300x250/v14/ad.js\"></script></div>",
          "adomain": ["shop.example.com"],
          "crid": "dco-300x250-v14",
          "w": 300,
          "h": 250,
          "mtype": 1,
          "apis": [7]
        }
      ]
    }
  ]
}

4 of 4 rows

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`adm`	The markup the ad server or SDK will render; here, a container that loads the DCO template
`crid`	The creative ID buyers and sellers use for approvals; one ID per template version keeps audits simple
`mtype`	1 means banner markup in OpenRTB 2.6
`apis`	7 tells the seller this ad needs OMID 1.0 in the rendering environment

`adm`

Meaning: The markup the ad server or SDK will render; here, a container that loads the DCO template

`crid`

Meaning: The creative ID buyers and sellers use for approvals; one ID per template version keeps audits simple

`mtype`

Meaning: 1 means banner markup in OpenRTB 2.6

`apis`

Meaning: 7 tells the seller this ad needs OMID 1.0 in the rendering environment

Download JSON

Table by AdSovereign, CC BY 4.0.

Field meanings come from OpenRTB 2.6 and the OMSDK note above. Every field is walked through in OpenRTB 2.6 explained. Viewability metrics themselves are defined in viewability, attention and brand safety.

Rendering in DSPs and ad servers

The same template renders differently depending on who serves it. Plan for each path before launch.

5 of 5 rows

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DSP with HTML5 upload (for example DV360)	The DSP's ad server returns your ZIP's HTML	clickTag, 5 MB download, 100 HTTP calls, 30 s animation
Third-party ad server tag in a DSP	A creative wrapper or tag calls your ad server, which calls the DCO platform	Extra hop latency; macros for click and impression tracking passed through
Publisher ad server after header bidding	Prebid Universal Creative pulls the winning ad from Prebid's cache	SafeFrame or iframe path; correct size; `hb_format` key-value
In-app	SDK web view, often MRAID	MRAID version support; OM SDK integration
CTV and video players	Player loads VAST, then the SIMID file if supported	SIMID support on the device; fallback to linear video

DSP with HTML5 upload (for example DV360)

What renders the ad: The DSP's ad server returns your ZIP's HTML
What to check: clickTag, 5 MB download, 100 HTTP calls, 30 s animation

Third-party ad server tag in a DSP

What renders the ad: A creative wrapper or tag calls your ad server, which calls the DCO platform
What to check: Extra hop latency; macros for click and impression tracking passed through

Publisher ad server after header bidding

What renders the ad: Prebid Universal Creative pulls the winning ad from Prebid's cache
What to check: SafeFrame or iframe path; correct size; hb_format key-value

In-app

What renders the ad: SDK web view, often MRAID
What to check: MRAID version support; OM SDK integration

CTV and video players

What renders the ad: Player loads VAST, then the SIMID file if supported
What to check: SIMID support on the device; fallback to linear video

Download JSON

Table by AdSovereign, CC BY 4.0.

For header bidding, the Prebid Universal Creative is a set of rendering routines that pull a given ad ID from Prebid's cache. Since Prebid.js 10.11.0 the library sets an hb_ver key-value that ad servers can use to load a specific version (Prebid.org, Prebid Universal Creative). In SafeFrames it asks Prebid.js for the winning ad over postMessage and draws it in a new iframe. The wrapper side is covered in the Prebid.js guide, and day-to-day trafficking in ad ops explained.

Testing and QA: a ten-step pipeline

Automate everything that has a number. Leave people to judge what only a human can see: copy, brand fit and the odd feed row that reads badly.

Lint and build. Bundle, minify and gzip each template; fail the build on any external call to an unapproved domain.
Check the weight budget. Measure gzipped kB per load phase and file requests against the strictest limit for each size.
Check the clickTag. Confirm the variable exists, is not minified and opens a new window, as DV360 requires.
Validate the feed. Every row against the field contract: lengths, image sizes, dates, a single default row.
Render every row. Screenshot each feed row in each size; flag text overflow and missing images.
Test the heavy ad limits deterministically. Chrome adds noise to its thresholds for privacy. Set chrome://flags/#heavy-ad-privacy-mitigations to Disabled to apply them exactly in testing (Chrome for Developers).
Listen for interventions in production. Chrome reports heavy ad removals through the Reporting API with the ID HeavyAdIntervention, which a ReportingObserver in the ad frame can capture.
Verify Open Measurement. Run the OM SDK compliance verification script; since version 1.6.9 the project documents how to self-host it (changelog).
Preview targeting rules. Test at least three values per rule plus the empty case. Google's checklist asks for three locations or IDs and a default test (Google, Studio Help).
Freeze during QA. Turn off scheduled feed uploads while testing, as Google advises, so the content you approve is the content that ships.

The first four steps fit a continuous integration (CI) job. The file below is our illustrative budget format; a build script reads it and fails if any limit is exceeded.

{
  "template": "boots-300x250",
  "version": "v14",
  "limits": {
    "initial_load_kb_gzip": 150,
    "subload_kb_gzip": 300,
    "initial_file_requests": 10,
    "total_download_mb": 4,
    "http_calls": 100,
    "animation_seconds": 30
  },
  "checks": {
    "clicktag_present": true,
    "clicktag_not_minified": true,
    "subload_after_window_load_event": true,
    "no_audio_autoplay": true,
    "omid_session_client_included": true
  },
  "feed": {
    "required_fields": ["row_id", "is_default", "headline", "image", "exit_url"],
    "max_headline_chars": 28,
    "max_image_kb": 45,
    "exactly_one_default_row": true
  }
}

The total_download_mb value is set to 4, not 5, on purpose. DV360 allows 5 MB, but Chrome unloads an ad above 4 MB of network use without interaction, so the browser is the binding limit.

Common mistakes

Testing the template, not the feed. Most DCO failures come from data: a long name, a missing image, an expired price.
No default row. Without one, unmatched impressions fall back to other creatives or nothing at all.
Minifying the clickTag. The ad server cannot find the variable and clicks go nowhere.
Loading everything before the page's load event. It breaks the LEAN initial-load budget and slows the publisher's page.
Trusting a shared-library exemption you never confirmed. Unnamed libraries count in full.
Building to the DSP's limit instead of the browser's. A 5 MB ad passes DV360 and gets unloaded by Chrome.
Shipping VPAID for interactivity. Use SIMID for interactive video and OM SDK for verification.
Changing feed IDs without republishing. Rules keep pointing at old IDs and serve the default everywhere.

FAQ

What is the file size limit for HTML5 banners?

The IAB New Ad Portfolio recommends 150 kB gzipped for the initial load of a 300x250 and 300 kB for the subload (IAB Tech Lab, 2017). Platforms add hard caps, such as DV360's 5 MB total download, and Chrome unloads ads above 4 MB of network use. Publishers can set stricter limits, so check each specification.

What is the difference between SIMID and VPAID?

VPAID ran ad code inside the video player and let the creative play the video. SIMID runs the interactive layer in a cross-origin iframe, talks to the player only by postMessage and leaves video playback to the player. That makes SIMID usable with server-side ad insertion, which VPAID was not (SIMID 1.2).

How does clickTag work in an HTML5 ad?

The ad declares a clickTag variable holding the landing page URL and opens it on click. The ad server replaces the value with its own click-tracking URL at serve time. DV360 requires click tags, warns against minifying them and requires the landing page to open in a new tab or window (Google, DV360 Help).

Can Google Ad Manager serve dynamic creatives built in Studio?

No. Google's Studio documentation says dynamic creatives are available for Campaign Manager 360 users and not for Google Ad Manager (Google, Studio Help). Publishers using Ad Manager can still serve third-party DCO tags or HTML5 creatives built elsewhere.

How do I test for Chrome's heavy ad intervention?

Disable chrome://flags/#heavy-ad-privacy-mitigations so Chrome applies the thresholds exactly, then use DevTools CPU and network throttling to mimic slow devices. In production, capture intervention reports through the Reporting API (Chrome for Developers, updated 7 January 2026).

How this works on owned infrastructure

A DCO pipeline is only as current as its feed, and the rules engine needs audience and product data at serve time. When the DCO platform, the ad server and the measurement sit with separate vendors, that data is copied into each of them and every feed update waits for their sync. AdSovereign includes an HTML5 creative and DCO layer that runs inside the same stack as the bidder and ad server, deployed in the customer's own cloud account or data centre. Feed rows, rules and render logs then stay in one place the team controls, and a variation's performance joins the bid logs without an export. The HTML5 DCO demo shows a template being filled from a feed, and the architecture page shows where the rules engine sits.

Sources

IAB Technology Laboratory, "IAB New Ad Portfolio: Fixed Size Ad Specifications" with LEAN load guidance (2017; file hosted April 2019). https://www.iab.com/wp-content/uploads/2019/04/IABNewAdPortfolio_LW_FixedSizeSpec.pdf
IAB, "Display & Mobile Advertising Creative Format Guidelines, updated for HTML5" (last updated 29 September 2015). https://www.iab.com/wp-content/uploads/2015/11/IAB_Display_Mobile_Creative_Guidelines_HTML5_2015.pdf
Chrome for Developers, "Understand Chrome's Heavy Ad Interventions" (published 22 September 2025, last updated 7 January 2026). https://developer.chrome.com/docs/web-platform/heavy-ads-intervention
Google, Display & Video 360 Help, "Guidelines for HTML5 display creatives" (accessed 9 November 2026). https://support.google.com/displayvideo/answer/10261241?hl=en
Google, Studio Help, "About dynamic creatives" (accessed 9 November 2026). https://support.google.com/richmedia/answer/2691686?hl=en
Google, Studio Help, "Dynamic creatives with feeds" QA checklist (accessed 9 November 2026). https://support.google.com/richmedia/answer/6310576?hl=en
IAB Tech Lab, "Secure Interactive Media Interface Definition (SIMID) 1.2" (file added 23 July 2026; releases 1.1 of 25 January 2022 and 1.0 of 28 June 2019). https://github.com/InteractiveAdvertisingBureau/SIMID/blob/master/SIMID%201.2.md
IAB Tech Lab, VAST4.x repository: VAST 4.3 (December 2022) and VAST 4.4 draft ("Publication Date TBD", commits July to September 2026). https://github.com/InteractiveAdvertisingBureau/VAST4.x
IAB Tech Lab, "Advertising Common Object Model (AdCOM) v1.0", List: API Frameworks (accessed 9 November 2026). https://github.com/InteractiveAdvertisingBureau/AdCOM/blob/main/AdCOM%20v1.0%20FINAL.md
IAB Tech Lab, "OpenRTB support for OMSDK" (AdCOM repository, accessed 9 November 2026). https://github.com/InteractiveAdvertisingBureau/AdCOM/blob/main/OpenRTB%20support%20for%20OMSDK.md

More sources (2)

IAB Tech Lab, Open-Measurement-JSClients repository and changelog (version 1.6.12, 2 November 2026). https://github.com/InteractiveAdvertisingBureau/Open-Measurement-JSClients/blob/master/CHANGELOG.md
Prebid.org, "Prebid Universal Creative" (accessed 9 November 2026). https://docs.prebid.org/overview/prebid-universal-creative.html

Author: Art Kukharenko, CEO, AdSovereign. Published: 10 November 2026. Last updated: 10 November 2026.

Key facts

Definition

How a DCO pipeline works: template, feed, rules, render

Templates: an HTML5 shell that survives every ad server

Feeds and rules: the data contract

is_default

active_from, active_to

targeting

headline_max_chars

image.width, image.height

image.max_kb

reporting_label

File-weight and load limits, side by side

Initial load, 300x250

Subload, 300x250

Initial load, 970x250 billboard

Total network

File or HTTP requests

CPU

Animation

Slow networks

Not counted

Worked budget for a 300x250 dynamic banner

index.html with inline CSS

Template script, bundled and minified

Feed row JSON

Product image, 600x500 WebP

Logo SVG

Web font subset

Initial total

Animation sprite sheet

Second product image

Subload total

Video and CTV: VAST, SIMID and the end of VPAID

Where the ad code runs

Who plays the video file

Communication

Server-side ad insertion

Verification

Resource MIME type

Measurement: Open Measurement inside the creative

adm

crid

mtype

apis

Rendering in DSPs and ad servers

DSP with HTML5 upload (for example DV360)

Third-party ad server tag in a DSP

Publisher ad server after header bidding

In-app

CTV and video players

Testing and QA: a ten-step pipeline

Common mistakes

FAQ

How this works on owned infrastructure

Sources

`is_default`

`active_from`, `active_to`

`targeting`

`headline_max_chars`

`image.width`, `image.height`

`image.max_kb`

`reporting_label`

`index.html` with inline CSS

`adm`

`crid`

`mtype`

`apis`