usefulweb.site DataFresh

Developer & data tools

DataFresh

Is this dataset or API still fresh? Newest record, update cadence check and schema drift.

Public http(s) JSON or CSV, max 2 MiB.

Leave empty to detect (updated_at, date, …). Nested: parent.child

hours

24 = daily, 168 = weekly, 720 ≈ monthly, 8760 = yearly.

Stores only a hash of the URL plus the field list.

Try an example: Stale daily feed · Yearly CSV with schema change

How it works

Point DataFresh at a public JSON or CSV endpoint (or paste the content). It finds the records, infers a schema with a stable fingerprint, finds the newest timestamp, compares its age with the update cadence you expect, and reports schema changes since the last check – as one of: healthy, stale, schema_changed, unavailable, no_timestamp.

  • Records: a JSON root array, or the largest array of objects within 3 levels; CSV uses the first row as header (comma or semicolon).
  • Schema: every field (one nesting level flattened as parent.child) with its observed value types and presence ratio; the fingerprint is the first 16 hex chars of SHA-256 over sorted "field:types" lines.
  • Timestamp: the field you name, otherwise the first field named like updated/modified/timestamp/date/time/year where ≥ 80% of values parse as dates (ISO 8601, epoch s/ms, YYYY, YYYY-Qn, DD.MM.YYYY). Years count as 31 Dec, quarters as their last day.
  • Freshness: age = now − newest timestamp. healthy if age ≤ 1.5 × expected interval, otherwise stale. Without a timestamp field the HTTP Last-Modified header is used if present.
  • Drift: compared with the previous schema you paste or, with "remember", the schema stored for the same URL (key = SHA-256 of the URL). Any added/removed field or type change → schema_changed (takes precedence over healthy, not over unavailable).

For scripts and AI agents

  • JSON API: POST https://datafresh.usefulweb.site/api/v1/calculate (same calculation as this page)
  • Interface description: OpenAPI 3.1 · AI guide: llms.txt
  • MCP server (Streamable HTTP): https://datafresh.usefulweb.site/mcp · tool name datafresh
Example request
curl -s -X POST https://datafresh.usefulweb.site/api/v1/calculate \
  -H 'content-type: application/json' \
  -d '{"content":"{\"meta\":{\"source\":\"example\"},\"items\":[{\"id\":1,\"value\":3.2,\"updated_at\":\"2026-10-01T06:00:00Z\"},{\"id\":2,\"value\":4.1,\"updated_at\":\"2026-10-03T06:00:00Z\"}]}","expectedCadenceHours":24}'

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