Streams

Raw chain event firehose — cursor-paginated REST, idempotent, replayable.

Streams expose the same event surface every Foundation Dataset decoder consumes internally. Page forward with a cursor, replay from any point, and never miss an event. For push delivery to your backend, see Subscriptions.

Streams reads require an API key — send it as Authorization: Bearer.

curl -H "Authorization: Bearer $SL_API_KEY" \
  "https://api.secondlayer.tools/v1/streams/events?limit=100"

Each response returns a next_cursor. Pass it back as cursor to continue exactly where you left off — deliveries are idempotent, so retries never double-count.

curl -H "Authorization: Bearer $SL_API_KEY" \
  "https://api.secondlayer.tools/v1/streams/events?cursor=7970329:8"

Narrow the firehose by event type, contract, or principal — types, contract_id, sender, recipient, asset_identifier, and from_height/to_height. Filters are exact-match; event types without a given field simply don't match.

curl -H "Authorization: Bearer $SL_API_KEY" \
  "https://api.secondlayer.tools/v1/streams/events?types=ft_transfer&sender=SP...&limit=50"

• Finality — tip.finalized_height plus a finalized flag on every event, anchored to Bitcoin (burn-block) confirmations. A finalized event won't reorg.
• Caching — fully-finalized pages are served Cache-Control: public, immutable with an ETag (and 304 on If-None-Match); the moving tip stays short-lived.
• Signed responses — every read carries an ed25519 X-Signature. Fetch the public key at /public/streams/signing-key and verify, or set verify on the SDK client — trust the data without trusting the server.
• Bulk + replay — download finalized history as parquet (sl streams pull, or the SDK dumps namespace) and events.replay({ from: "genesis" }) to backfill cold history then tail live with no gap at the seam.

See the changelog for the full list.