The whole product, over HTTP.

# reproducibility metadata - free, no auth, at every tier
curl https://apexdatum.io/api/v1/manifest

# the catalog, annotated with what your key can read
curl -H "Authorization: Bearer ep_live_..." https://apexdatum.io/api/v1/packages

# one package, every dataset in it, gated by your plan
curl -H "Authorization: Bearer ep_live_..." https://apexdatum.io/api/v1/packages/td-equity

X-RateLimit-Limit      5,000     your effective daily allowance
X-RateLimit-Remaining  what is left today
X-RateLimit-Used       requests counted, including any rejected over the limit
X-RateLimit-Reset      unix seconds - the next UTC midnight
X-RateLimit-Degraded   present only if the counter was unreadable and we let you through

429 carries Retry-After. Rejected requests still count, deliberately -
otherwise a client can hammer a closed door for free. If the quota counter
itself is unavailable the request is allowed rather than refused, and says so:
you are already authorised at that point, and breaking a paid product to
defend a fair-use ceiling is the wrong trade.

Export formats: csv, json. XLSX and Parquet are not served - a format we cannot round-trip byte-identically through the release archive would break the reproducibility promise the archive exists to make, so we publish the two we can prove rather than the four that would demo well.

{
  "package":  { "id", "number", "name", "parameters", "limits" },
  "access":   { "tierId", "tierNumber", "level", "redactedFields", "upgrade" },
  "dataset":  { "version", "season", "week", "generatedAt" },
  "meta":     { "<dataset>": { "totalRows", "returnedRows", "truncated" } },
  "datasets": { "<dataset>": [ ... ] },
  "disclaimer": "..."
}