How do I capture and replay bid requests for QA?
Answer
Sample and log raw request bodies at your edge (before any normalization), strip or hash user identifiers, and store them as fixtures. Replaying them serves two purposes: regression-testing your own parser and bidding logic against real traffic shapes, and validating the payloads against the spec to catch drift when a partner changes what they send. A nightly job that runs the latest sample through rtblint validate --stdin with --format json will surface a partner's new or moved fields the day they appear instead of the week revenue dips.
Go deeper
More questions on debugging, no-bids, and validation
- Why is my bidder not receiving bid requests? Work the path from the exchange inward: confirm the endpoint the exchange has on file matches what you deployed (scheme, host, path), that your endpoint returns a well-formed response or HTTP 204 quickly enough to stay under the exchange's timeout, and that traffic filters on the exchange side (geo, media type, QPS caps, pretargeting) are not excluding you.
- Why is my bid rate low even though I receive requests? Start by separating deliberate no-bids from failures.
- How do I find out why my bids are losing auctions? Ask for loss reasons via the loss notice URL.
- How do I debug a systematic OpenRTB no-bid? If the bidder returns a BidResponse with nbr set, the code tells you where to look: nbr 2 is Invalid Request, which means the bidder could not parse or accept your bid request, so run the request through a validator before anything else.
- What does HTTP 204 mean in OpenRTB, and how is it different from nbr? HTTP 204 No Content is the spec's preferred way for a bidder to say it has no bid: no body, cheapest possible round trip.
- How do I validate an OpenRTB bid request? Paste it into a validator that checks against the actual spec catalog, not just JSON syntax.
All 93 questions are listed in the OpenRTB FAQ.