xDai Stable Chain xDai Stable Chain BlockScout BlockScout TokenBridge TokenBridge

FAQ: BlockScout Environment Variables

Note: The up-to-date list of ENV variables is also located in the BlockScout Documentation.

Below is a table outlining the environment variables utilized by BlockScout.

Variable Required Description Default Version
NETWORK :white_check_mark: Environment variable for the main EVM network such as Ethereum Network or POA Network POA Network
SUBNETWORK :white_check_mark: Environment variable for the subnetwork such as Core or Sokol Network Sokol Testnet
NETWORK_ICON :white_check_mark: Environment variable for the main network icon or testnet icon. Two options are _test_network_icon.html and _network_icon.html _test_network_icon.html
LOGO :white_check_mark: Environment variable for the logo image location. The logo files names for different chains can be found here /images/blockscout_logo.svg
ETHEREUM_JSONRPC_VARIANT :white_check_mark: This environment variable is used to tell the application which RPC Client the node is using (i.e. Geth, Parity, or Ganache) parity
ETHEREUM_JSONRPC_HTTP_URL :white_check_mark: The RPC endpoint used to fetch blocks, transactions, receipts, tokens. localhost:8545
ETHEREUM_JSONRPC_TRACE_URL The RPC endpoint specifically for the Geth/Parity client used by trace_block and trace_replayTransaction. This can be used to designate a tracing node. localhost:8545
ETHEREUM_JSONRPC_WS_URL :white_check_mark: The WebSockets RPC endpoint used to subscribe to the newHeads subscription alerting the indexer to fetch new blocks. ws://localhost:8546
NETWORK_PATH Used to set a network path other than what is displayed in the root directory. An example would be to add /eth/mainnet/ to the root directory. (empty)
SECRET_KEY_BASE :white_check_mark: Use mix phx.gen.secret to generate a new Secret Key Base string to protect production assets. (empty)
CHECK_ORIGIN Used to check the origin of requests when the origin header is present. It defaults to false. In case of true, it will check against the host value. false
PORT :white_check_mark: Default port the application runs on is 4000 4000
COIN :white_check_mark: The coin here is checked via the Coinmarketcap API to obtain USD prices on graphs and other areas of the UI POA
METADATA_CONTRACT This environment variable is specifically used by POA Network to obtain Validators information to display in the UI. (empty)
VALIDATORS_CONTRACT This environment variable is specifically used by POA Network to obtain the Emission Fund contract. (empty)
SUPPLY_MODULE This environment variable is used by the xDai Chain/RSK in order to tell the application how to calculate the total supply of the chain. You don’t need to set this ENV variable for other chains. It should be TokenBridge in case of xDai chain and rsk in case of RSK false
SOURCE_MODULE This environment variable is used to calculate the total supply and is specifically used by the xDai Chain. You don’t need to set this ENV variable for others chains. For xDai chain the value should be TransactionAndLog false
DATABASE_URL Production environment variable to define the Database endpoint. (empty)
POOL_SIZE Production environment variable to define the number of database connections allowed. 20
ECTO_USE_SSL Production environment variable to use SSL on Ecto queries. true
DATADOG_HOST Host configuration setting for Datadog integration (empty)
DATADOG_PORT Port configuration setting for Datadog integration. (empty}
SPANDEX_BATCH_SIZE Spandex and Datadog configuration setting. (empty)
SPANDEX_SYNC_THRESHOLD Spandex and Datadog configuration setting. (empty)
HEART_BEAT_TIMEOUT Production environment variable to restart the application in the event of a crash. 30
HEART_COMMAND Production environment variable to restart the application in the event of a crash. systemctl restart explorer.service
BLOCKSCOUT_VERSION Added to the footer to signify the current BlockScout version. (empty) v1.3.4+
RELEASE_LINK The link to Blockscout release notes in the footer. https://github.com/poanetwork/blockscout/releases/tag/${BLOCKSCOUT_VERSION} v1.3.5+
ELIXIR_VERSION Elixir version to install on the node before Blockscout deploy. (empty)
BLOCK_TRANSFORMER Transformer for blocks: base or clique. base v1.3.4+
GRAPHIQL _TRANSACTION Default transaction in query to GraphiQL. (empty) v1.3.4+
FIRST_BLOCK The block number, where indexing begins from. 0 v1.3.8+
TXS_COUNT_CACHE_PERIOD Interval in seconds to restart the task, which calculates the total txs count. 60 * 60 * 2 v1.3.9+
ADDRESS_WITH_BALANCES_UPDATE_INTERVAL Interval in seconds to restart the task, which calculates addresses with balances. 30 * 60 v1.3.9+
LINK_TO_OTHER_EXPLORERS true/false. If true, links to other explorers are added in the footer (empty)
COINMARKETCAP_PAGES the number of pages on coinmarketcap to list in order to find token’s price 10
SUPPORTED_CHAINS Array of supported chains that displays in the footer and in the chains dropdown. This var was introduced in this PR #1900 and looks like an array of JSON objects. (empty) v2.0.0+
BLOCK_COUNT_CACHE_PERIOD time to live of cache in seconds. This var was introduced in #1876 600 v2.0.0+
ALLOWED_EVM_VERSIONS the comma-separated list of allowed EVM versions for contracts verification. This var was introduced in #1964 “homestead, tangerineWhistle, spuriousDragon, byzantium, constantinople, petersburg” v2.0.0+
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