How is the request sent?

Through the FizzKit relay (/api/proxy) so the bidder sees a server-side POST with content-type: application/json and x-openrtb-version: 2.6. Latency is measured relay-to-bidder and compared with tmax. Local or private targets that the relay refuses fall back to a direct browser fetch.

What does the gzip toggle do?

The body is compressed in your browser with CompressionStream and sent with content-encoding: gzip, which is how many exchanges actually transmit bid requests. The bytes sent are shown next to the response.

What do the consistency checks cover?

For every bid: impid exists in the request, response cur is in the request cur list, price is at or above the impression floor, the response id matches the request id and each bid has an id. Semantic warnings from the summary engine (mtype vs adm, missing adomain, burl without ${AUCTION_PRICE}) are listed as well.

Can I share a request with a colleague?

Use "Copy link" to encode the request model in the URL (up to 8 KB), "Copy JSON" or "Copy cURL". Larger requests can be saved as named presets in your browser.

OpenRTB Request Builder

Compose a complete OpenRTB 2.6 BidRequest without hand-typing JSON. Start from a preset (display banner, instream video, native, CTV app, audio, multi-imp) and edit every section in a form: impressions with banner formats, video mimes/protocols/plcmt/skip, a native asset builder, PMP deals and floors; site or app inventory; device with one-click fill from your own UA and Client Hints (device.sua); user IDs and eids; GDPR, GPP, us_privacy and COPPA regs; source.tid and a SupplyChain node builder; raw ext. The form and the JSON editor stay in sync in both directions and the request is validated as you type. Send it to any bidder URL — or your own RTB Bidder Sandbox — through the FizzKit relay with gzip, tmax and custom headers, then read the response: status, latency versus tmax, bids table, warnings and request/response consistency checks. Keep a history of the last 20 sends and diff any two requests.

Fetches URLs via the FizzKit relay — nothing is stored

Presets

Form on the left, JSON on the right — both stay in sync. ⌘Enter sends.

attmaxmscurcomma separatedtestbcatcomma separatedbadvcomma separated

Media types

Banner formats first one becomes banner.w/h

pos

api

Blocked attributes / types (battr, btype)

battr

btype

bidfloorbidfloorcursecureinstlrwddtagidext.gpid

PMP deals (0) private_auction

BidRequest JSON

497 chars · 33 lines

Validation

None of site / app / dooh provided — exchanges usually reject this.
None of site / app / dooh is present.

Impressions

Types

banner

Size

289 B

tmax

200 ms

Errors

Warnings

RTB Bidder Sandbox

A live OpenRTB bidder endpoint that captures every bid request and answers with bids, no-bids, custom templates or timeouts.

Bid Response Inspector

Decode an OpenRTB BidResponse: bids, macros, no-bid reasons, creative preview and win/billing notice firing.

OpenRTB Inspector

Validate & annotate OpenRTB 2.6 BidRequest and BidResponse JSON.

User-Agent Parser

Parse any User-Agent — browsers, in-app webviews, CTV (Roku, Tizen, webOS, Fire TV), bots — merge Client Hints and get an OpenRTB device object.

IAB TCF Consent Decoder

Decode TCF v2.2 consent strings with vendor names from the Global Vendor List, a purpose × vendor matrix and an encoder.

IAB GPP Decoder

Decode and edit Global Privacy Platform strings — US National and state sections with plain-English legends, TCF EU, gpp_sid checks.

How to use OpenRTB Request Builder

1Pick a preset or paste an existing BidRequest into the JSON editor — the form fills itself.
2Adjust impressions, inventory, device (or click "Use my UA"), user, regs and supply chain in the form; the JSON updates live.
3Fix anything flagged in the validation list under the JSON editor.
4Open the Send tab, enter a bidder URL or pick "My Bidder Sandbox", set tmax and gzip, then press ⌘Enter to send and read the response.

About OpenRTB Request Builder

OpenRTB Request Builder is part of FizzKit — a collection of focused developer and ad-tech tools. This tool uses the FizzKit relay to fetch public URLs on your behalf (so browser CORS rules do not get in the way); fetched content is returned to your browser and not stored.

Frequently asked questions

Yes. When you paste or edit JSON, unknown keys at the root, imp, site/app, device, user, regs and source levels are preserved and written back when the form regenerates the JSON. BidRequest.ext is kept as raw JSON text.

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