Log-level data

Log-level data is the record-by-record output of an ad server, exchange or DSP, one row per bid request, impression, click or conversion, with its timestamps, identifiers, prices and decision fields, as opposed to the aggregated reports those systems present in their user interfaces.

Access to log-level data is what separates owning a stack from renting one. Google Ad Manager sells it as Data Transfer reports, hourly files of impression, click, bid and activity events (Google Ad Manager, Data Transfer reports). DSPs and SSPs offer it at a price or not at all. Without it a publisher cannot do demand path optimization and an advertiser cannot audit a DSP's fees, which is why the ANA's transparency benchmarks required participating advertisers to obtain log-level data from their DSPs and SSPs before the 43.9% working-media figure for 2024 could be computed (ExchangeWire, 16 September 2026).

For retail media, log-level data is also a measurement requirement. The IAB/MRC guidelines recommend SKU-level reporting "where relevant unless otherwise unavailable" and require disclosure of extrapolation; neither is possible from aggregates (IAB/MRC, January 2024). IAB Europe's V2.1 names "open data sources, APIs provided by the CMN" as one of three delivery tools (IAB Europe, V2.1).

Example row (bid log, simplified): ts=2026-10-17T10:00:00.123Z req_id=80ce… imp_id=1 seat=buyer-7 bid=2.10 floor=1.50 won=1 clear=2.10 deal=DL-2026-001 schain_len=2 gdpr=1 tcf_purposes=1,2,7 eid_source=uid2. Multiply by 200,000 per second to see why storage design is the first decision.

Related: DPO, working media, ad server, closed-loop measurement.

Source: Google Ad Manager Data Transfer documentation (as the reference implementation); IAB/MRC Retail Media Measurement Guidelines (January 2024) on SKU-level reporting.

1. Google Ad Manager, Data Transfer reports
2. ExchangeWire, 16 September 2026
3. IAB/MRC, January 2024
4. IAB Europe, V2.1