# Environment variables

The client's configuration is managed through the `.env` file. Generally, you will need to configure the **BTC\_RPC\_URL**, which can be set either through the [client's menu](/guides-of-data-consensus/others/operation-references/common-operations/set-btc-rpc-node.md) or by directly editing the `.env` file.

* **Synchronizer**: Requires a Bitcoin full node.
* **Validator**: Both Bitcoin full node and light node works.

Other configurations can be adjusted as needed.

```
# network configurations mainnet or testnet
NETWORK=mainnet

# Logger configurations
# Maximum size for each log file (30 MB)
# LOGGER_MAX_SIZE=30m

# Directory where log files are stored
# LOGGER_DIR=logs

# Maximum age for log files (30 days)
# LOGGER_MAX_FILES=30d

# ExSat RPC URLs configurations
# You can leave it empty to use the default exSat configuration.
# Configure this as an array, with the best-performing URL as the first element to serve as the primary node.
# For testnet use: ["https://chain-tst3.exactsat.io"]
# For mainnet use: ["https://rpc-us.exsat.network", "https://rpc-sg.exsat.network"], or other custom nodes.
EXSAT_RPC_URLS=[]

# Bitcoin RPC URL
BTC_RPC_URL=

# Bitcoin RPC username
BTC_RPC_USERNAME=

# Bitcoin RPC password
BTC_RPC_PASSWORD=

################################################################################

# Synchronizer configurations(is required only for the synchronizer)
# Size of each upload chunk (256 KB). Be careful! Modifying this configuration may cause block uploading failure. It must not be less than 100 KB.
# CHUNK_SIZE=262144

# Scheduler for block upload jobs (every second)
# SYNCHRONIZER_JOBS_BLOCK_UPLOAD=*/1 * * * * *

# Scheduler for block verify jobs (every second)
# SYNCHRONIZER_JOBS_BLOCK_VERIFY=*/1 * * * * *

# Scheduler for block parse jobs (every 5 seconds)
# SYNCHRONIZER_JOBS_BLOCK_PARSE=*/5 * * * * *

# File path to the synchronizer's keystore
SYNCHRONIZER_KEYSTORE_FILE=

# Password for the synchronizer's keystore
SYNCHRONIZER_KEYSTORE_PASSWORD=

################################################################################

# Validator configurations(is required only for the validator)
# Scheduler for endorsement jobs (every second)
# VALIDATOR_JOBS_ENDORSE=*/1 * * * * *

# Scheduler for endorsement check jobs (every 1 minute)
# VALIDATOR_JOBS_ENDORSE_CHECK=0 * * * * *

# File path to the validator's keystore
VALIDATOR_KEYSTORE_FILE=

# Password for the validator's keystore
VALIDATOR_KEYSTORE_PASSWORD=

################################################################################

# Enable prometheus
PROMETHEUS=false

# Prometheus listen address
PROMETHEUS_ADDRESS=0.0.0.0:9900

################################################################################
```


---

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