# hap.io

> hap.io provides free traffic estimates for websites and apps, computed from open rank data (Tranco, Cisco Umbrella, Majestic, OpenPageRank). Estimates are modelled, not measured. Typical accuracy is about 2.3x median fold error. hap.io does not publish traffic channel splits, demographics, or app DAU/MAU, because those require panel/SDK data that is not available free.

## Data access for agents

- Dataset metadata (model, counts, build date): https://hap.io/data/meta.json
- Top 500 websites by rank (JSON): https://hap.io/data/top.json
- Per-domain records live in 256 sharded JSON files: https://hap.io/data/shards/{xx}.json where xx is the FNV-1a 32-bit hash of the domain mod 256, as two lowercase hex digits. Each shard maps domain -> {r: rank, v: estimated monthly visits, lo/hi: range, t: tier, u: Umbrella rank, m: Majestic rank, rd: referring subnets, src: model}.
- Full agent guide: https://hap.io/agents.md

## Pages

- Home / search: https://hap.io/
- About the data and its limits: https://hap.io/about
- For AI agents: https://hap.io/agents