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wolkjs is a client library for the Wolk API, implemented in JavaScript. It's available on npm as a node module.

To use wolkjs, for your desired database type (NoSQL or SQL), you MUST either

Instructions for setting up and testing your own node can be found HERE.

Please note that the library is still under development and may not be stable.

If you require further assistance, feel free to shoot us an email:


To use WOLK API, you need to install the corresponding library.

$ npm install wolkjs

Connect to Plasma Node

Open a connection by specifying the host and port of the Plasma node.

var wolkjsAPI = require("wolkjs");

var PLASMAHOST = "";
var PLASMAPORT = "80";

var plasmanode = new wolkjsAPI(PLASMAADDR);

Plasma Operations

Retrieve Plasma Tokens and Token Balances

Retrieve plasma tokens and token balance by specifying address and block number

var registered_address = "0xAA96B58F7ee51d2445fE596C3535874F5E206B14";
var blockNumber = "latest";
var plasmaBalance = plasmanode.getPlasmaBalance(registered_address, blockNumber);
// plasmaBalance result:
{ account:
   { tokens: [ '0x1962836485220a62' ],
     denomination: '0x2386f26fc10000',
     balance: '0x2386f26fc10000' } 

Retrieve BlockchainID

Retrieve blockchainID by specifying tokenID and block number

var tokenId = plasmaBalance.account.tokens[0];
var tokenObject = plasmanode.getPlasmaToken(tokenId, "latest");
// tokenObject result
{ token:
   { denomination: '0x2386f26fc10000',
     prevBlock: '0x3',
     owner: '0xaa96b58f7ee51d2445fe596c3535874f5e206b14',
     balance: '0x2386f26fc10000',
     allowance: '0x0',
     spent: '0x0' },
   { depositIndex: '0x3c',
     denomination: '0x2386f26fc10000',
     depositor: '0xaa96b58f7ee51d2445fe596c3535874f5e206b14',
     tokenID: '0x1962836485220a62' } 

var blockchainID = plasmanode.getBlockchainID(tokenId, tokenObject.tokenInfo.depositIndex);
// blockchainID result: '0xcd778162be0d4f2'

Send Initial Anchor Transaction

To register your blockchain with the plasma node by sending the initial anchor transaction

// For all initial Anchor Transactions, use 0x03c85f1da84d9c6313e0c34bcb5ace945a9b12105988895252b88ce5b769f82b
var genesisBlockHash = "0x03c85f1da84d9c6313e0c34bcb5ace945a9b12105988895252b88ce5b769f82b";

var rlp = require('rlp');
var web3 = require('web3');
web3Obj = new web3();
var atxExtra = [ [ registered_address ], [] ];
var anchorTxJson = { "blockchainID": blockchainID, "blocknumber": "0x0", "blockhash": genesisBlockHash, "extra": atxExtra, "sig": '' };
var anchorTx = [
var encodedAnchorTx = rlp.encode(anchorTx);
var encodedAnchorTxAsHex = encodedAnchorTx.toString('hex');
var shortHash = web3.sha3(encodedAnchorTxAsHex, {encoding:'hex'});

// Example of signing with Metamask
alert("Check Metamask to Approve Signing and Sending Order");
web3.eth.sign(registered_address, shortHash,
  function(err, sig) {
    if(!err) {
      console.log("Sending AnchorTX")
      anchorTx.sig = sig;

Configure Wolk Node

For the next steps you will need to have a running WolkDB node * If you set up your own WolkDB node, make sure to set the blockchainId to the blockchainID retrieved via the steps described above * If you registered your address directly with the WolkDB Public Gateway, you should have received the corresponding blockchainID for the selected database type. Please contact if you did not. Those using the public gateway MUST use the blockchainID returned for their requests to work.

Steps for downloading and launching docker can be found at: ___

Connect to Wolk Node

Open a connection by specifying configuration options like host and port

var HOST = "localhost"
var PORT = "24000"
var WOLKADDR = "http://" + HOST + ":" + PORT

var wolknode = new wolkjsAPI(WOLKADDR)

NoSQL Operations


Set a key value pair

wolknode.setKey("blockchainID", "key", "val")

// setKey result:
{ txhash:
   '2471d3ed40ba6ddb3ff0ea12cdae2f378d6ef146025d5a2b3ef02325af9d0677' }


Get the value corresponding to a given key

var value = wolknode.getKey("blockchainID", "key")

// getKey result:
{ proof: '{"token":"07855b46a623a8ec","proofBits":"0","proof":[]}',
  value: 'valueA' }

SQL Operations

Create database

Create a database by specifying your blockchainID, the requesttype ("CreateDatabase"), an owner (will be specific to your blockchain) and database name.

var createDatabaseCommand = { "requesttype":"CreateDatabase", "owner":"wolkdb.eth", "database":"testdb" }
wolknode.exec(blockchainID, createDatabaseCommand)
// result:
{ txhash: "4450a4f4fde8f0b49d83d2ec3b1185cdc66b287748e546afa55571d887021cc8" }

List databases

List existing databases by specifying your blockchainID, the requesttype ("ListDatabases"), an owner (will be specific to your blockchain) and (optionally) the blocknumber. If blocknumber is not included, the request defaults to returning data that corresponds with the latest block minted.

var listDatabasesCommand = { "requesttype":"ListDatabases", "owner":"wolkdb.eth", "blocknumber":1 })
wolknode.exec(blockchainID, listDatabasesCommand)
// result:
  result: {
    data: [{
        database: "testdb"
    matchedrowcount: 1

Create table

Create a table by specifying your blockchainID and a CREATE TABLE SQL statement.

Note: current supported types for columns are string, integer, float and a table must have a primary key.

var createTableSQL = "CREATE TABLE demoitems(ID string primary key, Name string, Description string, Price float, Currency string, Hash string)";
var createTableCommand = { "requesttype":"CreateTable", "owner":"wolkdb.eth", "database":"testdb", "query": createTableSQL }
sql.exec(blockchainID, createTableCommand)
// result:
  txhash: "98827bbd28f1cf65f91dbc0abdb7e50e6bb4a9d4fb69283b1ca5ff828c686a9b"

Describe Table

To see the table definition of a table, specify your blockchainID along with the owner by specifying table name.

var describeTableCommand = { "requesttype":"DescribeTable", "owner":"wolkdb.eth", "database":"testdb", "table":"demoitems" }
sql.exec(blockchainID, describeTableCommand)

List Tables

To list the tables that belong to a given database, specify your blockchainID, owner, database and (optionally) blocknumber

var listTablesCommand = { "requesttype":"ListTables", "owner":"wolkdb.eth", "database":"testdb", "blocknumber":3 }
sql.exec(blockchainID, listTablesCommand)

// result:
  result: {
    data: [{
        table: "demoitems"
    matchedrowcount: 1


var sql1 = "INSERT INTO demoitems(ID, Name, Description, Price, Currency, Hash) VALUES('ID1','Item1','Hot Item #1',0.11,'ethereum', 'Qmd286K6pohQcTKYqnS1YhWrCiS4gz7Xi34sdwMe9USZ7u')";
var sql2 = "INSERT INTO demoitems(ID, Name, Description, Price, Currency, Hash) VALUES('ID2','Item2','Hot Item #2',0.09,'ethereum', 'Qme1gTwdtFaUMoqwTNWX5SdYmNfiAj4N88qujbxmsX5z6u')";
var queryCommand = { "requesttype":"Query", "owner":"wolkdb.eth", "database":"testdb", "query": sql1 };
sql.exec(blockchainID, queryCommand);

var queryCommand = { "requesttype":"Query", "owner":"wolkdb.eth", "database":"testdb", "query": sql2 }
sql.exec(blockchainID, queryCommand)


var sql3 = "SELECT * FROM demoitems"
var sql4 = "SELECT * FROM demoitems WHERE price > 0.10"
var queryCommand = { "requesttype":"Query", "owner":"wolkdb.eth", "database":"testdb", "query": sql3 }
var rows = sql.exec(blockchainID, queryCommand)
// result:
  result: {
    data: [{
        ID: "ID1",
        Name: "Item1",
        Description: "Hot Item #1",
        ID: "ID2",
        Name: "Item2",
        Description: "Hot Item #2",
    matchedrowcount: 2


var sql5 = "UPDATE demoitems SET Price = 0.13 WHERE ID='ID2'"
var queryCommand = { "requesttype":"Query", "owner":"wolkdb.eth", "database":"testdb", "query": sql5 }
sql.exec(blockchainID, queryCommand)


var sql6 = "DELETE FROM demoitems WHERE ID='ID1'"
var queryCommand = { "requesttype":"Query", "owner":"wolkdb.eth", "database":"testdb", "query": sql6 }
sql.exec(blockchainID, queryCommand)

Drop table

Drop a table by specifying table name.

var dropTableCommand = { "requesttype":"DropTable", "owner":"wolkdb.eth", "database":"testdb", "table":"demoitems" }
sql.exec(blockchainID, dropTableCommand)

Drop database

Drop a database by specifying owner and database name.

var dropDatabaseCommand = { "requesttype":"DropDatabase", "owner":"wolkdb.eth", "database":"testdb" }
sql.exec(blockchainID, dropTableCommand)


The SWARMDB API uses the following error codes:

Error Code Meaning
400 Bad JSON supplied: [JSON]
401 SQL Parsing error: [SQLError in SQL]
402 Key Not Found: [key]
403 Table Does Not Exist: Table: [tableName] Owner: [ownerID]
404 Column Does Not Exist in table definition: [columnName]
405 No Primary Key specified in Create Table
406 Multiple Primary keys specified in Create Table
407 Invalid ColumnType: [columnType]
408 Invalid IndexType: [indexType]
409 Max Allowed Columns exceeded - [Num Columns] supplied, max is [MaxNumColumns]
410 Max Allowed Record size exceeded - [RecordSize] provided,
411 SWARM Error on Write [Details]
412 SWARM Error on Read [Details]
413 ENS Error
414 Invalid Challenge Response
415 Insufficient Permissions
416 No Table Owner specified
417 Table Owner mismatch
418 Request Invalid
419 Invalid Signature Length: Must be 65 characters
420 Invalid Signature: Unable to Retrieve Public Key
421 User Address not configured on connected node.
422 Unable to decode response
423 Error Decoding Signed Message
424 Error In HTTP Request
425 Invalid Query Request. Missing Rawquery
426 Table Name Missing
427 Mismatched Column Types
428 Row missing primary key
429 Row contains unknown column [columnName]
430 TableOwner Missing
431 Scans on Column [column] not unsupported due to indextype
432 WHERE Clause contains invalid column [column name]
433 GET Request Missing Key
434 Record with key [keyvalue] already exists. If you wish to modify, please use UPDATE SQL statement or PUT
435 Invalid Row Data
436 Unable to converty byte array to Row Object
437 ColumnType [type] not SUPPORTED. Value [value] rejected
438 Invalid Request Body
439 Failure to store [CHUNKTYPE] Chunk
440 Enable to retrieve [CHUNKTYPE] Chunk