OpenRTB validator · open source · Apache 2.0
Validate OpenRTB
before it bids.
RTBlint checks OpenRTB bid requests against the published specification: malformed JSON, missing required fields, unknown and deprecated fields, moved paths, type mismatches, and documented enums. Version-aware across OpenRTB 2.0–3.0, from one Rust core that runs in your browser, in your terminal, and in your pipeline.
cargo install rtblintnpm install rtblint-corertblint validate request.jsonSpec deltas tracked
62+
Versions covered
2.0 → 3.0
Runs
In your browser
License
Apache 2.0
Version-aware by design
One validator, every OpenRTB version
The spec has evolved continuously since 2012. Fields move, deprecate, and appear with each release. RTBlint tracks those deltas so a finding always reflects the version you are validating against, not a single frozen snapshot.
2.0
2012
4
Unified display, mobile, and video around shared objects.
2.1
2012
3
Tier-2 categories, geo provenance.
2.2
2014
4
Native ads, video skip signaling.
2.3
2015
5
Native 1.1 alignment, refined enums.
2.4
2016
4
Audio, metric reporting.
2.5
2016
6
supplychain groundwork, source object.
2.6
2022–2025
29
Eight tracked snapshots: plcmt, DSA, GPP, durfloors, refresh.
3.0
2018
7
Layered model with AdCOM. Envelope and AdCOM 1.0 domain objects.
Each square is one tracked spec delta. OpenRTB 2.6 alone spans eight published snapshots from 2022 to 2025.
What RTBlint checks
The errors that drop a request
A malformed bid request does not bid. RTBlint catches the structural mistakes that exchanges reject and bidders silently misread, each one mapped to the field that caused it.
Malformed JSON & missing fields
Parse errors and absent required fields (imp, id, at) are caught before a request ever reaches an exchange.
Unknown & deprecated fields
Fields not in the targeted version, and fields the spec has since deprecated, are flagged with the exact path.
Moved paths across versions
When a field relocates between versions (placement → plcmt), RTBlint points to the new home.
Type mismatches
Integers where strings appear, objects where arrays belong: type errors that silently break bidding logic.
Documented enum values
Values outside the documented set for fields like auction type and placement are reported against the spec.
Version-aware checks
Validate against a specific OpenRTB version, or let RTBlint detect and check the latest tracked snapshot.
Every finding is actionable
A rule ID and a path, not a guess
RTBlint does not just say a request is invalid. Each issue names the rule that fired and the exact JSON path, so it maps straight to the line to fix and stays stable enough to gate a build on.
placement was superseded by plcmt in OpenRTB 2.6. Set plcmt for forward compatibility.
Why trust this validator
Grounded in the spec, run on your terms
Derived from the published spec
Every rule traces to the IAB Tech Lab OpenRTB specification: required fields, deprecations, moves, and documented enums. Each finding cites the version it applies to.
Runs entirely in your browser
The validator is the RTBlint Rust core compiled to WASM. Nothing is uploaded; every check happens client-side and returns instantly.
Stable rule IDs and JSON paths
Each issue carries a stable rule ID and the exact JSON path that tripped it, so a finding maps straight to the field to fix, in a report or in CI.
One core, many surfaces
Validate in the browser, the terminal, and the pipeline
Browser tester
Paste a bid request and validate instantly, client-side. Nothing is uploaded.
Open the tester →Rust CLI
rtblint validate request.json, with --stdin, --version, and --format json for CI.
MCP server
A hosted Model Context Protocol server at rtblint.org/mcp, so an AI agent can validate OpenRTB payloads mid-conversation.
Latest from the blog
Spec releases, decoded as they ship
Fraudulent CTV bundle IDs mimic each platform's ID grammar. OpenRTB validates shape, not spoof.
Analysis of the 50 highest-traffic fraudulent CTV bundle IDs finds brand spoofing on Roku, ASIN-style mimicry on Fire TV, numeric ID mimicry on Samsung, and mobile bundles in CTV streams. A well-formed app.bundle passes schema checks while the identity claim is false.
Read the post →A CTV app delisted from the store can still bid. The auction keys on bundle ID, not shelf status.
Pixalate's August 2026 CTV pre-bid blocklist flags apps removed from stores that continue generating programmatic traffic. Impression-level IVT does not catch that gap; app-level exclusion does, because OpenRTB never carries whether the store still lists the bundle.
Read the post →OpenRTB has two JSON encodings, and ARTF's own sample corpus uses both
The OpenRTB specification types 28 flag fields as integers. The IAB OpenRTB protobuf schema declares those same fields bool. Both encodings are in the wild, a payload valid in one is invalid in the other, and two of the five ARTF reference samples cannot be parsed by the protobuf JSON parser the framework runs on.
Read the post →Roadmap
Where RTBlint is, and where it is going
- Shipped
OpenRTB 2.x bid request & response validation
Required fields, unknown and deprecated paths, type mismatches, and documented enums across the tracked 2.6 snapshots, plus bid response validation.
- Shipped
Browser tester, Rust CLI, npm library & hosted MCP server
The same Rust core in the browser, as the RTBlint CLI and rtblint-core crate, as the rtblint-core npm package, and as a hosted MCP server at rtblint.org/mcp.
- Shipped
OpenRTB 3.0 envelope + AdCOM 1.0 domain objects
Layered 3.0 transport validation, plus the AdCOM catalog behind item.spec, bid.media, and request.context.
- Shipped
Opt-in supply-chain resolution
CLI --resolve --cache checks each payment hop against sellers.json and the publisher's ads.txt or app-ads.txt. The core stays offline.
- Shipped
NDJSON stream lint
CLI --batch --summary lints captured bid streams and ranks rule ids by how often they fire.
- Shipped
Exchange dialect profiles
Validate against a platform's documented protocol requirements on top of the spec. google-ab covers Authorized Buyers extras (at=3, Imp.ext.billing_id). prebid-server covers Prebid Server /openrtb2/auction extras (bidder or stored request per Imp, no wseat/bseat). xandr covers Microsoft Monetize extras. magnite covers xAPI identity fields.
- Shipped
GitHub Action
uses: aleksUIX/rtblint@<tag> downloads a prebuilt CLI and fails the job on spec errors.
- Planned
Native Go & Python bindings
The same Rust core embeddable directly in Go and Python ad-serving pipelines.
FAQ
OpenRTB validation, answered
What is an OpenRTB validator?
An OpenRTB validator checks a programmatic bid request (or response) against the IAB Tech Lab OpenRTB specification. It reports malformed JSON, missing required fields, unknown or deprecated fields, moved paths, type mismatches, and out-of-range enum values, the structural mistakes that cause exchanges to drop a request or bidders to misread it. RTBlint does this version-aware, in the browser, with a rule ID and JSON path on every finding.
Which OpenRTB versions does RTBlint support?
RTBlint carries object catalogs for OpenRTB 2.0 through 3.0. Rule depth is richest on the tracked 2.6 snapshots (2022 through 2025), which is where most live programmatic traffic sits today. You can validate against a specific version or let RTBlint check against the latest tracked snapshot.
Is RTBlint free and open-source?
Yes. RTBlint is open-source under the Apache 2.0 license. There is no account, no rate limit, and no paywall. The browser tester, the Rust core, and the CLI are all free.
Does RTBlint upload my bid request?
No. Validation runs entirely client-side via the RTBlint Rust core compiled to WebAssembly. Your bid request JSON never leaves the browser and nothing is logged or retained.
Can I run RTBlint in CI or a pipeline?
Yes. RTBlint ships as a Rust CLI (rtblint validate <file.json>, or --stdin for piped input) with --version and --format json for version-aware, machine-readable output, so it drops into CI and pre-bid checks. An MCP server is included. Native Go and Python bindings are on the roadmap.
Is RTBlint an official IAB validator?
No. RTBlint is an independent, open-source validator that checks bid requests against the published IAB Tech Lab OpenRTB specification. It is not affiliated with or operated by IAB Tech Lab.
Validate an OpenRTB bid request now
Free, instant, nothing uploaded.