Electrum protocol specification

Stratum is a universal bitcoin communication protocol used mainly by bitcoin client Electrum and miners.

Format

Stratum protocol is based on JSON-RPC 2.0 (although it doesn’t include “jsonrpc” information in every message). Each message has to end with a line end character (n).

Request

Typical request looks like this:

{ "id": 0, "method":"some.stratum.method", "params": [] }
  • id begins at 0 and every message has its unique id number
  • list and description of possible methods is below
  • params is an array, e.g.: [ “1myfirstaddress”, “1mysecondaddress”, “1andonemoreaddress” ]

Response

Responses are similar:

{ "id": 0, "result": "616be06545e5dd7daec52338858b6674d29ee6234ff1d50120f060f79630543c"}
  • id is copied from the request message (this way client can pair each response to one of his requests)

  • result can be:

    • null

    • a string (as shown above)

    • a hash, e.g.:

      { "nonce": 1122273605, "timestamp": 1407651121, "version": 2, "bits": 406305378 }
      
    • an array of hashes, e.g.:

      [ { "tx_hash:
      "b87bc42725143f37558a0b41a664786d9e991ba89d43a53844ed7b3752545d4f",
      "height": 314847 }, { "tx_hash":
      "616be06545e5dd7daec52338858b6674d29ee6234ff1d50120f060f79630543c",
      "height": 314853 } ]
      

Methods

server.version

This is usually the first client’s message, plus it’s sent every minute as a keep-alive message. Client sends its own version and version of the protocol it supports. Server responds with its supported version of the protocol (higher number at server-side is usually compatible).

The version of the protocol being explained in this documentation is: 0.10.

request:

{ "id": 0, "method": "server.version", "params": [ "1.9.5", "0.6" ] }

response:

{ "id": 0, "result": "0.8" }

server.banner

request:

{ "id": 1, "method": "server.banner", "params": [] }

server.donation_address

server.peers.subscribe

Client can this way ask for a list of other active servers. Servers are connected to an IRC channel (#electrum at freenode.net) where they can see each other. Each server announces its version, history pruning limit of every address (“p100”, “p10000” etc.–the number means how many transactions the server may keep for every single address) and supported protocols (“t” = tcp@50001, “h” = http@8081, “s” = tcp/tls@50002, “g” = https@8082; non-standard port would be announced this way: “t3300” for tcp on port 3300).

Note: At the time of writing there isn’t a true subscription implementation of this method, but servers only send one-time response. They don’t send notifications yet.

request:

{ "id": 3, "method":
"server.peers.subscribe", "params": [] }<br/>

response:

{ "id": 3, "result": [ [ "83.212.111.114",
"electrum.stepkrav.pw", [ "v0.9", "p100", "t", "h", "s",
"g" ] ], [ "23.94.27.149", "ultra-feather.net", [ "v0.9",
"p10000", "t", "h", "s", "g" ] ], [ "88.198.241.196",
"electrum.be", [ "v0.9", "p10000", "t", "h", "s", "g" ] ] ]
}

blockchain.numblocks.subscribe

A request to send to the client notifications about new blocks height. Responds with the current block height.

request:

{ "id": 5, "method":
"blockchain.numblocks.subscribe", "params": [] }

response:

{ "id": 5, "result": 316024 }

message:

{ "id": null, "method":
"blockchain.numblocks.subscribe", "params": 316024 }

blockchain.headers.subscribe

A request to send to the client notifications about new blocks in form of parsed blockheaders.

request:

{ "id": 5, "method":
"blockchain.headers.subscribe", "params": [] }

response:

{ "id": 5, "result": { "nonce":
3355909169, "prev_block_hash":
"00000000000000002b3ef284c2c754ab6e6abc40a0e31a974f966d8a2b4d5206",
"timestamp": 1408252887, "merkle_root":
"6d979a3d8d0f8757ed96adcd4781b9707cc192824e398679833abcb2afdf8d73",
"block_height": 316023, "utxo_root":
"4220a1a3ed99d2621c397c742e81c95be054c81078d7eeb34736e2cdd7506a03",
"version": 2, "bits": 406305378 } }

message:

{ "id": null, "method":
"blockchain.headers.subscribe", "params": [ { "nonce":
881881510, "prev_block_hash":
"00000000000000001ba892b1717690900ae476857120a78fb50825f8b67a42d4",
"timestamp": 1408255430, "merkle_root":
"8e92bdbf1c5c581b5942fc290c6c52c586f091b279ea79d4e21460e138023839",
"block_height": 316024, "utxo_root":
"060f780c0dd07c4289aaaa2ef24723f73380095b31d60795e1308170ec742ffb",
"version": 2, "bits": 406305378 } ] }

blockchain.address.subscribe

A request to send to the client notifications when status (i.e., transaction history) of the given address changes. Status is a hash of the transaction history. If there isn’t any transaction for the address yet, the status is null.

request:

{ "id": 6, "method":"blockchain.address.subscribe", "params": ["1NS17iag9jJgTHD1VXjvLCEnZuQ3rJDE9L"] }

response:

{ "id": 6, "result":"b87bc42725143f37558a0b41a664786d9e991ba89d43a53844ed7b3752545d4f" }

message:

{ "id": null, "method":"blockchain.address.subscribe", "params": ["1NS17iag9jJgTHD1VXjvLCEnZuQ3rJDE9L","690ce08a148447f482eb3a74d714f30a6d4fe06a918a0893d823fd4aca4df580"]}

blockchain.address.get_history

For a given address a list of transactions and their heights (and fees in newer versions) is returned.

request:

{"id": 1, "method": "blockchain.address.get_history", "params": ["1NS17iag9jJgTHD1VXjvLCEnZuQ3rJDE9L"] }

response:

{"id": 1, "result": [{"tx_hash": "ac9cd2f02ac3423b022e86708b66aa456a7c863b9730f7ce5bc24066031fdced", "height": 340235}, {"tx_hash": "c4a86b1324f0a1217c80829e9209900bc1862beb23e618f1be4404145baa5ef3", "height": 340237}]}
{"jsonrpc": "2.0", "id": 1, "result": [{"tx_hash": "16c2976eccd2b6fc937d24a3a9f3477b88a18b2c0cdbe58c40ee774b5291a0fe", "height": 0, "fee": 225}]}

blockchain.address.get_mempool

blockchain.address.get_balance

request:

{ "id": 1, "method":"blockchain.address.get_balance", "params":["1NS17iag9jJgTHD1VXjvLCEnZuQ3rJDE9L"] }

response:

{"id": 1, "result": {"confirmed": 533506535, "unconfirmed": 27060000}}

blockchain.address.get_proof

blockchain.address.listunspent

request:

{ "id": 1, "method":
"blockchain.address.listunspent", "params":
["1NS17iag9jJgTHD1VXjvLCEnZuQ3rJDE9L"] }<br/>

response:

{"id": 1, "result": [{"tx_hash":
"561534ec392fa8eebf5779b233232f7f7df5fd5179c3c640d84378ee6274686b",
"tx_pos": 0, "value": 24990000, "height": 340242},
{"tx_hash":"620238ab90af02713f3aef314f68c1d695bbc2e9652b38c31c025d58ec3ba968",
"tx_pos": 1, "value": 19890000, "height": 340242}]}

blockchain.utxo.get_address

blockchain.block.get_header

blockchain.block.get_chunk

blockchain.transaction.broadcast

Submits raw transaction (serialized, hex-encoded) to the network. Returns transaction id, or an error if the transaction is invalid for any reason.

request:

{ "id": 1, "method":
"blockchain.transaction.broadcast", "params":
"0100000002f327e86da3e66bd20e1129b1fb36d07056f0b9a117199e759396526b8f3a20780000000000fffffffff0ede03d75050f20801d50358829ae02c058e8677d2cc74df51f738285013c260000000000ffffffff02f028d6dc010000001976a914ffb035781c3c69e076d48b60c3d38592e7ce06a788ac00ca9a3b000000001976a914fa5139067622fd7e1e722a05c17c2bb7d5fd6df088ac00000000" }<br/>

response:

{"id": 1, "result": "561534ec392fa8eebf5779b233232f7f7df5fd5179c3c640d84378ee6274686b"}

blockchain.transaction.get_merkle

blockchain.transaction.get_merkle [$txid, $txHeight]

blockchain.transaction.get

Method for obtaining raw transaction (hex-encoded) for given txid. If the transaction doesn’t exist, an error is returned.

request:

{ "id": 17, "method":"blockchain.transaction.get", "params": [
"0e3e2357e806b6cdb1f70b54c3a3a17b6714ee1f0e68bebb44a74b1efd512098"
] }

response:

{ "id": 17, "result":"01000000010000000000000000000000000000000000000000000000000000000000000000ffffffff0704ffff001d0104ffffffff0100f2052a0100000043410496b538e853519c726a2c91e61ec11600ae1390813a627c66fb8be7947be63c52da7589379515d4e0a604f8141781e62294721166bf621e73a82cbf2342c858eeac00000000"}

error:

{ "id": 17, "error": "{ u'message': u'No information available about transaction', u'code': -5 }" }

blockchain.estimatefee

Estimates the transaction fee per kilobyte that needs to be paid for a transaction to be included within a certain number of blocks. If the node doesn’t have enough information to make an estimate, the value -1 will be returned.

Parameter: How many blocks the transaction may wait before being included.

request:

{ "id": 17, "method": "blockchain.estimatefee", "params": [ 6 ] }

response:

{ "id": 17, "result": 0.00026809 }
{ "id": 17, "result": 1.169e-05 }

error:

{ "id": 17, "result": -1 }