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blockSubscribe

Subscribes to new blocks and streams each full block — optionally filtered to blocks mentioning a given account or program — as it is confirmed or finalized.

Solanasol.pubsubpro+ — per-method tier gating on /ws/sol

blockSubscribe pushes entire blocks over the WebSocket as the cluster produces them, sparing you the poll-getBlocks-then-fetch-each-getBlock loop. Each blockNotification carries the slot and a block object in the same shape getBlock returns — blockhash, parent linkage, timestamp, rewards, and the transaction list at the detail level you configure.

The first parameter is a filter: the string "all" streams every block, while {"mentionsAccountOrProgram": "<pubkey>"} narrows the stream to blocks containing at least one transaction that references the given account or program — and in that case the notification's transaction list includes only the matching transactions, not the whole block's. The config object then controls payload weight: transactionDetails (full, accounts, signatures, or none), encoding (json, jsonParsed, base58, base64), showRewards, and maxSupportedTransactionVersion — set the latter to 0 or versioned transactions in the block will make decoding fail. commitment may be confirmed (default) or finalized; processed is not supported for block subscriptions.

Use it when you genuinely need block-granular data live: feeding a real-time indexer or analytics pipeline, computing per-block metrics (fees, compute units, transaction counts), or tailing all activity of one program with block-level ordering guarantees. If you only care about individual account changes or log lines, accountSubscribe/logsSubscribe are far lighter.

Caveats worth planning around. In stock Solana this method is marked unstable and only works on nodes started with the block-subscription flag enabled — Triport routes /ws/sol block subscriptions to capable nodes, but portability of your code to other RPC setups is not guaranteed. Full-detail notifications are large (hundreds of KB, easily multiple MB per block), so budget bandwidth and parsing time, and prefer transactionDetails: "signatures" or a mentions filter when you can. Skipped slots produce no notification. The stream is session-scoped: after a reconnect, resubscribe and backfill missed slots with getBlocks + getBlock. Stop with blockUnsubscribe.

Parameters

Positional params array: [filter, config?].

filterstring | objectrequired
"all", or {"mentionsAccountOrProgram": "<base-58 pubkey>"} to receive only blocks (and within them, only transactions) referencing the account/program.
configobjectoptional
Optional configuration object (see below).
commitmentstringoptional
confirmed (default) or finalized. processed is not supported.
encodingstringoptional
Transaction encoding: json (default), jsonParsed, base58, base64.
transactionDetailsstringoptional
full (default), accounts, signatures, or none.
showRewardsbooleanoptional
Whether to include the block's rewards array (default true).
maxSupportedTransactionVersionintegeroptional
Set to 0 to accept versioned transactions; omitting it makes blocks containing them error.

Response

Subscribe ack:

Each matching block is pushed as a blockNotification:

{
  "jsonrpc": "2.0",
  "method": "blockNotification",
  "params": {
    "subscription": 79015,
    "result": {
      "context": { "slot": 348392090 },
      "value": {
        "slot": 348392090,
        "err": null,
        "block": {
          "blockhash": "8qVzLxkQdWmnFDdVfKG2o1CwhQ5padJetGz9EYiHiHUV",
          "previousBlockhash": "5y2SSSY2ZJcpk1963PmdcTQjAyMevMSqYbwyR7oAR5oS",
          "parentSlot": 348392089,
          "blockTime": 1755500000,
          "blockHeight": 330122456,
          "signatures": [
            "5VERv8NMvzbJMEkV8xnrLkEaWRtSz9CosKDYjCJjBRnbJLgp8uirBgmQpjKhoR4tjF3ZpRzrFmBV6UjKdiSZkQUW"
          ]
        }
      }
    }
  }
}
result (on ack)integer
Subscription id — pass it to blockUnsubscribe.
params.result.context.slotinteger
Slot of the notification.
params.result.value.slotinteger
Slot of the block.
params.result.value.errobject | null
Set when the node failed to produce the block payload.
params.result.value.blockobject
The block, in getBlock shape at the configured detail level.

Errors

CodeMeaningWhen it happens
-32602Invalid paramsMalformed filter/config — e.g. commitment: "processed", or a versioned transaction with no maxSupportedTransactionVersion.
4003forbiddenYour tier is below pro (tier_insufficient; the frame carries required_tier and upgrade_url).
4029rate_limitedSubscribe rate exceeded for your tier.

Notes

  • Unstable in stock Solana: requires nodes started with the block-subscription flag; Triport routes to capable nodes, but don't assume the method exists on arbitrary RPC endpoints.
  • Payloads are heavy: prefer a mentions filter and transactionDetails: "signatures" unless you truly need full transactions.
  • No processed commitment, and skipped slots emit nothing.
  • Related methods: blockUnsubscribe, getBlock / getBlocks for backfill, and logsSubscribe / programSubscribe for lighter targeted streams.