Educational API

Six thin chain-stats endpoints for browser-side educational embeds. Block tip, halving countdown, mempool summary, supply, difficulty, USD spot. CORS-open, no auth, no rate limit. Built for embedding live data into teaching content without infrastructure on your end.

Endpoints

GET https://chainquery.com/api/edu/tip
GET https://chainquery.com/api/edu/halving
GET https://chainquery.com/api/edu/mempool-summary
GET https://chainquery.com/api/edu/supply
GET https://chainquery.com/api/edu/difficulty
GET https://chainquery.com/api/edu/price

No auth header. Access-Control-Allow-Origin: * on every response. Cache-Control set with a stale-while-revalidate=120 hint so well-behaved consumers can use a stale cached body while a background refresh runs.

Common envelope

{
  "schema_version": "1",
  "ts_utc":          "2026-05-13T18:42:01.234Z",
  "data_age_sec":    12,
  "stale":           false,
  "data":            { ... }
}

stale: true means "we couldn't refresh from the node; serving last-good data; consumer should display a 'last updated X ago' note rather than failing." Treat stale: true as a hint, not an error. data may be null if no cache exists yet (cold start mid-outage); render gracefully.

Example: live block tip

$ curl -s https://chainquery.com/api/edu/tip | jq '.data | {height, miner_coinbase_tag, tx_count}'
{
  "height": 949256,
  "miner_coinbase_tag": "< OCEAN.XYZ >",
  "tx_count": 528
}

Endpoint summary

Contract guarantees

• HTTP 200 always — never 5xx. Failure mode is stale: true.
• Access-Control-Allow-Origin: * on every response. Safe to call from any browser origin.
• The envelope shape is stable. New fields under data are forward-compatible; consumers should treat unknown fields as opaque.
• Schema bumps will increment schema_version. Existing clients should refuse mismatched versions and degrade gracefully.
• No rate limit today. If we ever need to add one we'll do it as a soft Retry-After hint, not a 429 wall.

When this is the right tool

• Embedding live chain stats in educational content (live block height in a glossary entry, halving countdown in a course chapter).
• Browser-side Svelte / React widgets where you don't want to stand up your own bitcoind.
• Hobby projects, blog post embeds, classroom demos.

When this is not the right tool

• Trading systems or fee-bidding that need sub-second freshness — Fee Pressure API is the auth'd paid feed with that SLA.
• Block-by-block deterministic replay — these endpoints are snapshots, not streams.
• Compliance / sanctions screening — see Sanctions Check API.