secondlayer
.md

Decode Clarity print events

You don't decode them: every print is indexed already parsed from Clarity into JSON, with the raw hex kept beside it. One key, one call:

$curl "$SECONDLAYER_API_URL/v1/index/events?event_type=print&contract_id=SM3VDXK3WZZSA84XXFKAFAF15NNZX32CTSG82JFQ4.sbtc-registry&order=desc&limit=1" \
-H "Authorization: Bearer sk-sl_…"
200response.jsonjson
{
"events": [
{
"cursor": "9348740:2",
"block_height": 9348740,
"block_time": "2026-10-28T17:42:12.000Z",
"tx_id": "0xfff08aecc097d418f55b98b10abe2bc6b1785b89b0ed1b80506fc15a375a14f9",
"tx_index": 0,
"event_index": 2,
"event_type": "print",
"contract_id": "SM3VDXK3WZZSA84XXFKAFAF15NNZX32CTSG82JFQ4.sbtc-registry",
"payload": {
"topic": "print",
"value": {
"amount": "40477",
"block-height": "973577",
"max-fee": "850",
"recipient": { "hashbytes": "0x98cfcc0a22d16a9ce131dd774ee0245a3b10dcfb", "version": "0x04" },
"request-id": "4636",
"sender": "SPEG24N6F52VPD8001H20TD317GHDD23GGVEZC56",
"topic": "withdrawal-create"
},
"raw_value": "0x0c0000000706616d6f756e74…"
}
}
],
"next_cursor": "desc:9348740:2",
"tip": { "block_height": 9348932, "finalized_height": 9348069, "lag_seconds": 18 },
"reorgs": []
}

The decoded tuple is value: uints are decimal strings, buffers are hex, principals are strings. raw_value is the hex you started from, kept so you can check the decode.

See each topic's fields

A contract prints different shapes under different topics. The print-schema call lists a contract's topics and each field's Clarity and TypeScript type.

$curl "$SECONDLAYER_API_URL/v1/index/contracts/SM3VDXK3WZZSA84XXFKAFAF15NNZX32CTSG82JFQ4.sbtc-registry/print-schema" \
-H "Authorization: Bearer sk-sl_…"
200response.jsonjson
{
"contract_id": "SM3VDXK3WZZSA84XXFKAFAF15NNZX32CTSG82JFQ4.sbtc-registry",
"topics": [
{
"topic": "withdrawal-create",
"count": 29,
"fields": [
{ "name": "amount", "camel_name": "amount", "clarity_type": "uint", "ts_type": "bigint" },
{ "name": "recipient", "camel_name": "recipient", "clarity_type": "(tuple (hashbytes (buff 32)) (version (buff 1)))", "ts_type": "{ hashbytes: string; version: string }" },
]
},
],
"sampled": true
}

Fields come back with their Clarity type, so you know recipient is a tuple before you parse it. The schema is sampled from indexed prints, so sampled: true means older topics may be missing.

A uint is a bigint in a subgraph handler (ts_type), but a decimal string in REST values.

Pick out one topic

The events feed filters by contract, not by topic. Keep the topic you want from the tuple's own topic key.

const withdrawals = page.events.filter(
(event) => (event.payload.value as { topic?: string } | undefined)?.topic === "withdrawal-create",
);
  • Prints that aren't tuples have no topic key; the schema lists them under *.
  • To be pushed one topic instead of reading it, a webhook trigger takes topic (Print fields).
  • Page with next_cursor, as in any decoded feed.

Tradeoff

Hosted reads are metered, with a free monthly allowance (What it costs). Reading a contract's prints means reading every topic it emits, so a chatty contract costs more rows than the topic you keep.

Every filter and the response schema: Decoded events by event_type and Print payload schemas. The shapes by contract: Print schemas.

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