diff --git a/src/lib/helpers.ts b/src/lib/helpers.ts
index 5d8dd65..b37993e 100644
--- a/src/lib/helpers.ts
+++ b/src/lib/helpers.ts
@@ -18,6 +18,35 @@ export const blockConfig = (
   endBlock: end,
 });
 
+/**
+ * Gets the RPC endpoint URL for a given chain ID.
+ *
+ * @param chainId the chain ID to get the RPC URL for
+ * @returns the URL of the RPC endpoint
+ */
+export const rpcEndpointUrl = (chainId: number): string => {
+  /**
+   * Reads the RPC URL for a given chain ID from the environment variable:
+   * RPC_URL_{chainId}. For example, for Ethereum mainnet the chainId is `1`,
+   * so the env variable can be set as `RPC_URL_1=https://eth.drpc.org`.
+   */
+  const envVarName = `RPC_URL_${chainId}`;
+
+  // no RPC URL provided in env var
+  if (!process.env[envVarName]) {
+    // throw an error, as the RPC URL is required and no defaults apply
+    throw new Error(`Missing '${envVarName}' environment variable`);
+  }
+
+  try {
+    return new URL(process.env[envVarName] as string).toString();
+  } catch (e) {
+    throw new Error(
+      `Invalid '${envVarName}' environment variable. Please provide a valid URL.`,
+    );
+  }
+};
+
 // default request per second rate limit for RPC endpoints
 const DEFAULT_RPC_RATE_LIMIT = 50;
 
diff --git a/src/plugins/base.eth/ponder.config.ts b/src/plugins/base.eth/ponder.config.ts
index 2bf7f04..338f782 100644
--- a/src/plugins/base.eth/ponder.config.ts
+++ b/src/plugins/base.eth/ponder.config.ts
@@ -2,7 +2,7 @@ import { type ContractConfig, createConfig, factory } from "ponder";
 import { http, getAbiItem } from "viem";
 import { base } from "viem/chains";
 
-import { blockConfig, rpcRequestRateLimit } from "../../lib/helpers";
+import { blockConfig, rpcEndpointUrl, rpcRequestRateLimit } from "../../lib/helpers";
 import { createPluginNamespace } from "../../lib/plugin-helpers";
 import { BaseRegistrar } from "./abis/BaseRegistrar";
 import { EarlyAccessRegistrarController } from "./abis/EARegistrarController";
@@ -23,7 +23,7 @@ export const config = createConfig({
   networks: {
     base: {
       chainId: base.id,
-      transport: http(process.env[`RPC_URL_${base.id}`]),
+      transport: http(rpcEndpointUrl(base.id)),
       maxRequestsPerSecond: rpcRequestRateLimit(base.id),
     },
   },
diff --git a/src/plugins/eth/ponder.config.ts b/src/plugins/eth/ponder.config.ts
index 5c4a216..8ecc94b 100644
--- a/src/plugins/eth/ponder.config.ts
+++ b/src/plugins/eth/ponder.config.ts
@@ -2,7 +2,7 @@ import { ContractConfig, createConfig, factory, mergeAbis } from "ponder";
 import { http, getAbiItem } from "viem";
 
 import { mainnet } from "viem/chains";
-import { blockConfig, rpcRequestRateLimit } from "../../lib/helpers";
+import { blockConfig, rpcEndpointUrl, rpcRequestRateLimit } from "../../lib/helpers";
 import { createPluginNamespace } from "../../lib/plugin-helpers";
 import { BaseRegistrar } from "./abis/BaseRegistrar";
 import { EthRegistrarController } from "./abis/EthRegistrarController";
@@ -27,7 +27,7 @@ export const config = createConfig({
   networks: {
     mainnet: {
       chainId: mainnet.id,
-      transport: http(process.env[`RPC_URL_${mainnet.id}`]),
+      transport: http(rpcEndpointUrl(mainnet.id)),
       maxRequestsPerSecond: rpcRequestRateLimit(mainnet.id),
     },
   },
diff --git a/src/plugins/linea.eth/ponder.config.ts b/src/plugins/linea.eth/ponder.config.ts
index 56972b6..0b13359 100644
--- a/src/plugins/linea.eth/ponder.config.ts
+++ b/src/plugins/linea.eth/ponder.config.ts
@@ -2,7 +2,7 @@ import { ContractConfig, createConfig, factory, mergeAbis } from "ponder";
 import { http, getAbiItem } from "viem";
 
 import { linea } from "viem/chains";
-import { blockConfig, rpcRequestRateLimit } from "../../lib/helpers";
+import { blockConfig, rpcEndpointUrl, rpcRequestRateLimit } from "../../lib/helpers";
 import { createPluginNamespace } from "../../lib/plugin-helpers";
 import { BaseRegistrar } from "./abis/BaseRegistrar";
 import { EthRegistrarController } from "./abis/EthRegistrarController";
@@ -23,7 +23,7 @@ export const config = createConfig({
   networks: {
     linea: {
       chainId: linea.id,
-      transport: http(process.env[`RPC_URL_${linea.id}`]),
+      transport: http(rpcEndpointUrl(linea.id)),
       maxRequestsPerSecond: rpcRequestRateLimit(linea.id),
     },
   },