diff --git a/README.md b/README.md
index c97a82e..18c5109 100644
--- a/README.md
+++ b/README.md
@@ -23,7 +23,7 @@ const client = new IterableClient({
   apiKey: 'your-api-key'
 });
 
-const user = await client.getUserByEmail('user@example.com');
+const user = await client.getUserByEmail({ email: 'user@example.com' });
 
 // Track event
 await client.trackEvent({
@@ -57,13 +57,15 @@ const client = new IterableClient({
 
 ### Environment Variables
 
-```bash
-ITERABLE_API_KEY=your-api-key     # Required
-ITERABLE_DEBUG=true               # Enable basic debug logging
-ITERABLE_DEBUG_VERBOSE=true       # Enable full body logging (includes PII)
-LOG_LEVEL=info                    # Log level
-LOG_FILE=./logs/iterable.log      # Log to file
-```
+| Variable | Description | Default |
+|----------|-------------|---------|
+| `ITERABLE_API_KEY` | API key (required when using `createIterableConfig()`) | — |
+| `ITERABLE_BASE_URL` | API base URL | `https://api.iterable.com` |
+| `ITERABLE_DEBUG` | Log HTTP requests/responses (headers redacted) to stderr | `false` |
+| `ITERABLE_DEBUG_VERBOSE` | Include response bodies in debug output (may contain PII) | `false` |
+| `LOG_LEVEL` | Log level (`error`, `warn`, `info`, `debug`, etc.) | `debug` when `ITERABLE_DEBUG` is set, otherwise `info` |
+| `LOG_FILE` | Write logs to a file | — |
+| `LOG_STDERR` | Write logs to stderr | `true` |
 
 ## Development
 
diff --git a/src/config.ts b/src/config.ts
index b6417ff..08f0f7a 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -20,9 +20,12 @@ export const config = createEnv({
     LOG_LEVEL: z
       .enum(["error", "warn", "info", "http", "verbose", "debug", "silly"])
       .default(
-        !process.env.NODE_ENV || process.env.NODE_ENV === "production"
-          ? "info"
-          : "debug"
+        process.env.ITERABLE_DEBUG === "true" ||
+          process.env.ITERABLE_DEBUG_VERBOSE === "true"
+          ? "debug"
+          : !process.env.NODE_ENV || process.env.NODE_ENV === "production"
+            ? "info"
+            : "debug"
       ),
     LOG_JSON: z.coerce.boolean().default(process.env.NODE_ENV === "production"),
     LOG_FILE: z.string().optional(),