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+# Environment variable reference
+
+This document lists commonly used environment variables when running a Base node.
+
+## Core variables
+
+- `L1_RPC_URL` – Ethereum L1 RPC endpoint
+- `OP_NODE_RPC_URL` – OP node RPC endpoint
+- `JWT_SECRET` – JWT secret for engine API authentication
+
+## Optional tuning
+
+- `LOG_LEVEL` – logging verbosity (info, debug)
+- `RETH_DB_PATH` – custom path for reth database
+- `GOMAXPROCS` – CPU tuning for Go services
+
+Update this document when introducing new configuration options.