Lookup block

Finds a block by position or time. Specify workchain and shard, then provide either: seqno (exact block number), lt (find block containing this logical time), or unixtime (find block closest to this timestamp). Returns the full block ID including hashes needed for verification.

GET /api/v2/lookupBlock

Try it

Lookup block

cURL

curl --request GET \
  --url https://toncenter.com/api/v2/lookupBlock \
  --header 'X-API-Key: <api-key>'

200

{
  "ok": true,
  "result": {
    "@type": "ton.blockIdExt",
    "workchain": 123,
    "shard": "<string>",
    "seqno": 123,
    "root_hash": "<string>",
    "file_hash": "<string>"
  },
  "@extra": "<string>"
}

Authorizations

X-API-Key · string · header · required

Query Parameters

workchain · integer<int32> · required

The workchain to query. Use -1 for masterchain (validators, system contracts, config) or 0 for basechain (regular accounts and contracts). Most user transactions happen on workchain 0.

shard · string · required

The shard identifier. Masterchain always uses -9223372036854775808. For basechain, shards split and merge dynamically. Use the shards endpoint to discover current shard configuration.

seqno · integer<int32>

Query state at a specific block height. If omitted, returns the current state. Use this to look up historical data at a specific point in time.

lt · string

Logical time of a block

unixtime · integer<int32>

UNIX timestamp of a block

Response

200

application/json

OK

Response containing the full block identifier.

ok · boolean · default: true · required

Indicates if the request succeeded. If false, check the error field for details.

result · object · required

The response data. Only present when ok is true.

Show child attributes

result. @type · enum<string> · default: ton.blockIdExt · required

Object type identifier.

Available options: ton.blockIdExt

result. workchain · integer · required

Workchain ID: -1 for masterchain, 0 for basechain. Most user transactions are on workchain 0.

result. shard · string · required

Shard identifier. A signed 64-bit integer. Masterchain uses -9223372036854775808.

result. seqno · integer · required

Block or wallet sequence number. For blocks, this is the block height. For wallets, increment this for each outgoing transaction.

result. root_hash · string · required

Merkle root hash of the block state tree. Used for cryptographic verification.

result. file_hash · string · required

Hash of the serialized block data. Together with root_hash, uniquely identifies a block.

@extra · string

Optional request ID that you can pass in the request and receive back in the response. Useful for matching async responses.