blockscout/docs/env-variables.md

BlockScout Env Variables

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

Variable	Required	Description	Default	Version
NETWORK	✅	Environment variable for the main EVM network such as Ethereum Network or POA Network	POA Network	all
SUBNETWORK	✅	Environment variable for the subnetwork such as Core or Sokol Network	Sokol Testnet	all
NETWORK_ICON	✅	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	all
LOGO	✅	Environment variable for the logo image location. The logo files names for different chains can be found here	/images/blockscout_logo.svg	all
ETHEREUM_JSONRPC_VARIANT	✅	This environment variable is used to tell the application which RPC Client the node is using (i.e. Geth, Parity, or Ganache)	parity	all
ETHEREUM_JSONRPC_HTTP_URL	✅	The RPC endpoint used to fetch blocks, transactions, receipts, tokens.	localhost:8545	all
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	all
ETHEREUM_JSONRPC_WS_URL	✅	The WebSockets RPC endpoint used to subscribe to the newHeads subscription alerting the indexer to fetch new blocks.	ws://localhost:8546	all
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)	all
SECRET_KEY_BASE	✅	Use mix phx.gen.secret to generate a new Secret Key Base string to protect production assets.	(empty)	all
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	all
PORT	✅	Default port the application runs on is 4000	4000	all
COIN	✅	The coin here is checked via the Coinmarketcap API to obtain USD prices on graphs and other areas of the UI	POA	all
METADATA_CONTRACT		This environment variable is specifically used by POA Network to obtain Validators information to display in the UI.	(empty)	all
VALIDATORS_CONTRACT		This environment variable is specifically used by POA Network to obtain the Emission Fund contract.	(empty)	all
SUPPLY_MODULE		This environment variable is used by the xDai Chain in order to tell the application how to calculate the total supply of the chain.	false	all
SOURCE_MODULE		This environment variable is used to calculate the total supply and is specifically used by the xDai Chain.	false	all
DATABASE_URL		Production environment variable to define the Database endpoint.	(empty)	all
POOL_SIZE		Production environment variable to define the number of database connections allowed.	20	all
ECTO_USE_SSL		Production environment variable to use SSL on Ecto queries.	true	all
DATADOG_HOST		Host configuration setting for Datadog integration	(empty)	all
DATADOG_PORT		Port configuration setting for Datadog integration.	(empty}	all
SPANDEX_BATCH_SIZE		Spandex and Datadog configuration setting.	(empty)	all
SPANDEX_SYNC_THRESHOLD		Spandex and Datadog configuration setting.	(empty)	all
HEART_BEAT_TIMEOUT		Production environment variable to restart the application in the event of a crash.	30	all
HEART_COMMAND		Production environment variable to restart the application in the event of a crash.	systemctl restart explorer.service	all
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)	all
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)	v1.3.0+
COINMARKETCAP_PAGES		the number of pages on coinmarketcap to list in order to find token's price	10	v1.3.10+
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+