Prebid Ad Unit Inspector
Parse a real `adUnits` snippet and break it down into ad-unit codes, media types, sizes, bidder counts, and duplicate patterns. This is useful when a page looks overloaded, when bidders are attached to the wrong unit, or when teams need to understand the auction shape quickly before debugging runtime issues. It focuses on the ad-unit layer instead of the broader page shell.
Break down ad units, sizes, and bidder density before auction complexity turns into guesswork.
What you can do here
- Audit a homepage or template with many placements.
- Check whether bidders are attached to the right units.
- Spot ad-unit duplication during refactors or migrations.
Before you start
- Paste a realistic `adUnits` snippet.
About Prebid Ad Unit Inspector
The Prebid Ad Unit Inspector reads `adUnits` snippets and extracts the information teams usually end up hunting for by hand: unit codes, media types, sizes, bidder lists, and duplicate patterns.
Use it to audit a page template, review a rollout, or clean up a cluttered ad-unit setup before it creates downstream auction problems.
Best uses for Prebid Ad Unit Inspector
- Audit a homepage or template with many placements.
- Check whether bidders are attached to the right units.
- Spot ad-unit duplication during refactors or migrations.
How to use Prebid Ad Unit Inspector
- Paste a real `adUnits` array.
- Inspect bidder counts, sizes, and duplicate unit issues.
- Use the output to simplify or verify the page setup.
What to paste in
- Paste a realistic `adUnits` snippet.
What you should see
- Parsed units, bidder counts, media types, sizes, and structural warnings.
Example checks
These are simple checks you can run when you want a real sample and a clear result to compare against.
Paste a realistic `adUnits` snippet.
Why run it: Audit a homepage or template with many placements.
What to look for: Parsed units, bidder counts, media types, sizes, and structural warnings.
Ad Unit Structure Is Often the Hidden Source of Header Bidding Complexity
Why ad units deserve separate inspection
Many header bidding problems are blamed on bidder behavior when the deeper issue is the shape of the `adUnits` configuration itself. One page may carry too many bidders on a single placement. Another may duplicate unit codes across templates. Another may mix sizes or media types in ways that make the auction harder to understand than it should be. Those are not edge cases. They are ordinary sources of operational drag in real Prebid integrations.
The reason ad-unit debugging is easy to skip is that teams often assume the structure is obvious from the code. In reality, a long array of nested objects becomes visually noisy fast. When you are trying to answer simple questions like how many bidders are attached to each unit or whether two units share the same code, raw source is a poor interface. A dedicated inspector turns the structure into something you can actually reason about.
That is useful in launch QA, in regression review, and in cleanup work. It is also useful for long-tail SEO because many searchers are not looking for 'Prebid' broadly. They are looking for a way to understand why a specific ad-unit setup feels too heavy or too messy.
What teams usually need to know first
The first questions are structural: how many ad units exist, what media types they use, which sizes are exposed, and how many bidders are attached to each one. After that comes hygiene. Are there duplicate unit codes? Are there units with no real bidder objects? Are some placements much heavier than others? These are simple questions conceptually, but answering them from raw code takes more time than it should.
A dedicated ad-unit view helps make those differences concrete. A homepage with seven bidders on one slot and two on another may still be a valid implementation, but it is not the same operationally. One unit may deserve special timeout attention, another may need cleanup, and a third may be a sign that legacy bidders were never removed after a migration.
This is also where the separation from config matters. Global config tells you how the auction is orchestrated. Ad units tell you what the auction is being asked to do. Teams need both views if they want a realistic picture of complexity.
Why cleaner ad-unit reviews improve operations
When ad-unit structure is easier to read, communication improves. Product, ad ops, and engineering can all discuss the same page shape using the same evidence. That reduces the amount of re-explaining that happens during rollout reviews and incident calls. Instead of sharing snippets and asking people to scroll through them, the team can point to a unit-by-unit summary.
This also creates a better bridge into optimization work. If one or two units carry most of the bidder density, you know where to focus first. If duplicate codes appear across the page, you know where to clean up first. The tool does not decide the business policy, but it makes the structure visible enough for the right people to make a decision faster.
For search visibility, this kind of page also competes differently from a generic Prebid article. It answers a more specific debugging job, which is exactly the sort of narrower intent a specialized site is more likely to win.
Troubleshooting
What to look for
- Parsed units, bidder counts, media types, sizes, and structural warnings.
Common issues
- A structurally clean ad-unit setup can still perform poorly at runtime.
- Pasting only one fragment of a larger setup may hide duplicate behavior elsewhere on the page.
Best practices
- Paste raw input so the tool can apply formatting consistently.
- If output looks wrong, validate the input for missing commas or tags.
- Use the example buttons above to sanity-check formatting and behavior.
Related tools
More tools in the header bidding category.
- Prebid Timeout Risk Analyzer - Diagnose Prebid auction timeout risk from real config snippets, adUnits, and optional bidder timing notes. Instead of only guessing from fetched HTML, the tool inspects timeout settings, auction pressure, identity delay markers, and pasted bidder outcomes so teams get a more actionable first-pass readout of why bids may be missing the auction.
- Prebid Config Inspector - Inspect a Prebid `pbjs.setConfig` snippet and surface the auction settings that actually shape runtime behavior: bidder timeout, timeout buffer, consent modules, user sync, floors, S2S, and more. This tool is built for engineers and ad-ops teams who need a fast readout of whether a configuration is sane before they open devtools or live auction logs. Paste a real config block and get concrete findings instead of guessing which modules are active.
- Prebid User ID Inspector - Inspect Prebid `userId` and `userSync` configuration to see which identity modules appear active, what storage types they use, whether consent markers are visible, and whether auction delay settings look aggressive. This gives teams a real first-pass identity and sync review that is specific to header bidding rather than generic privacy tooling.
- Schain Validator - Validate a Prebid or OpenRTB supply chain object by checking version, complete flag, node count, and missing `asi` / `sid` / `hp` fields. This is useful during supply-path reviews, reseller onboarding, or anytime a team needs to explain how a supply chain should look before it reaches bidders.
Related reading
More specific pages for the exact jobs this tool supports.
Audit Prebid Ad Units Before a Template Rollout
A structural workflow for ad-unit QA before template changes go live.
Spot Duplicate Prebid Ad Unit Codes on a Template
A focused QA workflow for duplicated ad-unit identifiers.
Measure Bidder Density on a Prebid Homepage
A structural complexity workflow for bidder-heavy pages.
Check Prebid Size Mix Before a New Device Rollout
A placement-size workflow for ad-unit QA.
Review Video Ad Units Before an Outstream Rollout
A video-ad-unit workflow for Prebid rollout QA.
Check Ad Unit Labels Before Device-Specific Rollouts
A label-and-targeting workflow for device-specific ad unit QA.
Spot Prebid Timeout Risk from Page Source
A faster first pass for timeout risk when you have the page URL before you have deep instrumentation.
Review Prebid Timeout Risk After Adding a New Bidder
A post-change timeout review for bidder rollouts.
Frequently asked questions
Is it free to use?
Yes. Core tools are free and accessible without signup.
Does it upload my data?
This tool runs locally in your browser. Data you paste or files you upload stay on your device and are not uploaded.
What if I spot a bug?
Please reach out via the Contact page with a reproduction example.
Does it validate every bidder param?
No. It focuses on the ad-unit structure and bidder placement, not full adapter-specific runtime validation.
Can it read JS-style ad unit objects?
Yes. It is designed for realistic Prebid-style object snippets.
Why inspect ad units separately from config?
Because auction density and bidder placement often explain failures even when the global config looks reasonable.
Helpful links
Standards & references
Official specs that inform how this tool interprets data.