Openchain Server Configuration

The configuration of Openchain server is handled through a JSON file named config.json. The file is stored under the data folder.

It is possible to override a configuration value through environment variables. The name of the variable should be the concatenation of all the components of the path, separated by the character :. For example: validator_mode:validator:allow_third_party_assets.


Here is the default file:

  "enable_transaction_stream": true,

  "storage": {
    "provider": "SQLite",
    "path": "ledger.db"

  // Define transaction validation parameters
  "validator_mode": {
    // Required: A random string used to generate the chain namespace
    "instance_seed": "",
    "validator": {
      "provider": "PermissionBased",
      // Enable /p2pkh/<address>/ accounts
      "allow_p2pkh_accounts": true,
      // Enable /asset/p2pkh/<address>/ accounts
      "allow_third_party_assets": true,
      // Base-58 addresses that must have admin rights
      "admin_addresses": [
      "version_byte": 76

  // Uncomment this and comment the "validator_mode" section to enable observer mode
  // "observer_mode": {
  //   "upstream_url": ""
  // },

  "anchoring": {
    "provider": "Blockchain",
    // The key used to publish anchors in the Blockchain
    "key": "",
    "bitcoin_api_url": "",
    "network_byte": 111,
    "fees": 5000,
    "storage": {
      "provider": "SQLite",
      "path": "anchors.db"

Root section

  • enable_transaction_stream: Boolean indicating whether the transaction stream websocket should be enabled on this instance.

storage section

provider defines which storage engine to use. The two built-in values are SQLite and MSSQL.

SQLite storage engine

If the storage provider is set to SQLite, the chain is stored locally using SQLite. In that case, the following setting is used:

  • path: The path of the Sqlite database, relative to the wwwroot/App_Data folder. Absolute paths are also allowed, however, make sure the user under which the DNX process is running has write access to the file.

MSSQL storage engine

If the storage provider is set to MSSQL, the chain is stored using Microsoft SQL Server. In that case, the following setting is used:

  • connection_string: The connection string to the SQL Server database.


Third party storage engines can be build and used by Openchain. The provider setting is used to identify at runtime which storage engine should be instantiated.

validator_mode and observer_mode sections

These two sections are mutually exclusive. Depending whether the instance is setup in validator mode or observer mode, either the validator_mode section or observer_mode section should be present.

In the case of validator mode:

  • validator_mode:instance_seed: A random string that should be unique to that instance. It is hashed to obtain a namespace specific to that instance.
  • validator_mode:validator:provider: The type of validation performed by the Openchain instance when transactions are submitted. The only supported values currently are PermissionBased, PermitAll and DenyAll.
    • PermitAll indicates that all transactions are valid, regardless of who signed them. Use this mostly for testing.
    • DenyAll indicates that all transactions are invalid, regardless of who signed them. Use this to set the chain in read-only mode.
    • See this section for more details about the implicit rules of the PermissionBased mode. The relevant configuration settings with the PermissionBased mode are the following:
      • validator_mode:validator:allow_p2pkh_accounts: Boolean indicating whether P2PKH accounts (/p2pkh/<address>/) are enabled.
      • validator_mode:validator:allow_third_party_assets: Boolean indicating whether thrid party issuance accounts (/asset/p2pkh/<address>/) are enabled.
      • validator_mode:validator:admin_addresses: List of strings representing all addresses with admin rights.
      • validator_mode:validator:version_byte: The version byte to use when representing a public key using its Bitcoin address representation.

In the case of observer mode:

  • observer_mode:upstream_url: The endpoint URL of the upstream instance to connect to. Transactions will be replicated using this endpoint.

anchoring section

This section contains configuration settings relative to publishing an anchor to preserve data integrity.

  • provider: Value defining which anchoring mode to use. Currently, the only supported value is Blockchain, and publishes a cumulative hash of the database onto a Bitcoin-compatible blockchain.

  • key: The private key to use (in WIF format) as the signing address for the proof of publication transactions.

  • bitcoin_api_url: The Coinprism API endpoint to use to list unspent outputs and broadcast the signed transaction. Valid values include:

  • network_byte: The network byte corresponding to the network on which the anchor transaction is published.

  • storage:provider: Value defining how to cache anchors locally. Currently, the only supported value is SQLite and caches data locally in a SQLite database.

  • storage:path: The path of the local anchor cache database, relative to the wwwroot/App_Data folder.