diff --git a/src/components/EditableSyntaxHighlighter/EditableSyntaxHighlighter.module.scss b/src/components/EditableSyntaxHighlighter/EditableSyntaxHighlighter.module.scss
index 017b4ff..5045982 100644
--- a/src/components/EditableSyntaxHighlighter/EditableSyntaxHighlighter.module.scss
+++ b/src/components/EditableSyntaxHighlighter/EditableSyntaxHighlighter.module.scss
@@ -59,15 +59,40 @@
     grid-column: 1 /-1;
     border-radius: inherit;
     border: 0;
-    word-break: break-all;
-    overflow: hidden;
+    overflow-y: hidden;
+    overflow-x: auto;
     padding: $spacing-05;
+    white-space: pre;
+  }
+
+  > .textarea {
+    padding-inline-start: calc(var(--line-number-width) + #{$spacing-05});
   }
 
   code {
     display: block;
-    inline-size: 100%;
-    white-space: pre-wrap !important;
+    min-inline-size: 100%;
+    inline-size: max-content;
+    white-space: pre !important;
+  }
+
+  :global(.linenumber) {
+    min-inline-size: var(--line-number-width) !important;
+    white-space: nowrap;
+    text-align: start !important;
+    padding-inline-end: $spacing-07 !important;
+    position: sticky;
+    inset-inline-start: 0;
+    &::before {
+      content: '';
+      inline-size: 100%;
+      background-color: var(--highlight-background);
+      position: absolute;
+      inset-block: 0;
+      inset-inline: -$spacing-05;
+      z-index: -1;
+      border-inline-end: 1px solid $border-subtle-00;
+    }
   }
 
   &.invalid {
@@ -76,6 +101,13 @@
       padding-inline-end: $spacing-10 !important;
     }
   }
+
+  &:focus-within :global(.linenumber) {
+    &::before {
+      inline-size: calc(100% - 2px);
+      inset-inline-start: calc(2px - $spacing-05);
+    }
+  }
 }
 
 .textarea {
diff --git a/src/components/EditableSyntaxHighlighter/EditableSyntaxHighlighter.tsx b/src/components/EditableSyntaxHighlighter/EditableSyntaxHighlighter.tsx
index a4c3fbc..48a636a 100644
--- a/src/components/EditableSyntaxHighlighter/EditableSyntaxHighlighter.tsx
+++ b/src/components/EditableSyntaxHighlighter/EditableSyntaxHighlighter.tsx
@@ -17,10 +17,18 @@
 import { FormLabel } from '@carbon/react';
 import { WarningFilled } from '@carbon/react/icons';
 import clsx from 'clsx';
-import { CSSProperties, ReactNode, TextareaHTMLAttributes } from 'react';
+import {
+  CSSProperties,
+  ReactNode,
+  TextareaHTMLAttributes,
+  useEffect,
+  useRef,
+  useState,
+} from 'react';
 import { Light as SyntaxHighlighter } from 'react-syntax-highlighter';
 import python from 'react-syntax-highlighter/dist/cjs/languages/hljs/python';
 import defaultStyle from 'react-syntax-highlighter/dist/cjs/styles/hljs/default-style';
+import { useResizeObserver } from 'usehooks-ts';
 import classes from './EditableSyntaxHighlighter.module.scss';
 
 const style: { [key: string]: CSSProperties } = {
@@ -122,7 +130,7 @@ interface Props
   onChange?: (value: string) => void;
   invalid?: boolean;
   readOnly?: boolean;
-  // showLineNumbers?: boolean;
+  showLineNumbers?: boolean;
 }
 
 export function EditableSyntaxHighlighter({
@@ -132,20 +140,84 @@ export function EditableSyntaxHighlighter({
   onChange,
   invalid,
   readOnly,
+  showLineNumbers,
   className,
-  // showLineNumbers,
   ...props
 }: Props) {
+  const [lineNumberWidth, setLineNumberWidth] = useState<number>(0);
+  const rootRef = useRef<HTMLDivElement>(null);
+  const preRef = useRef<HTMLPreElement>(null);
+  const textAreaRef = useRef<HTMLTextAreaElement>(null);
+
+  const PreTag = (preProps: any) => <pre {...preProps} ref={preRef} />;
+
+  const syncScroll = () => {
+    requestAnimationFrame(() => {
+      const preElement = preRef.current;
+      const textAreaElement = textAreaRef.current;
+
+      if (preElement && textAreaElement) {
+        preElement.scrollLeft = textAreaElement.scrollLeft;
+      }
+    });
+  };
+
+  const checkLineNumberWidth = () => {
+    if (!preRef.current) {
+      return;
+    }
+
+    const lineNumberElement = [
+      ...preRef.current.querySelectorAll('.linenumber'),
+    ].at(-1);
+
+    setLineNumberWidth(
+      lineNumberElement ? (lineNumberElement as HTMLElement).offsetWidth : 0,
+    );
+  };
+
+  useEffect(() => {
+    const textAreaElement = textAreaRef.current;
+
+    if (textAreaElement) {
+      textAreaElement.addEventListener('scroll', syncScroll);
+      textAreaElement.addEventListener('input', syncScroll);
+      textAreaElement.addEventListener('paste', syncScroll);
+    }
+
+    return () => {
+      if (textAreaElement) {
+        textAreaElement.removeEventListener('scroll', syncScroll);
+        textAreaElement.removeEventListener('input', syncScroll);
+        textAreaElement.removeEventListener('paste', syncScroll);
+      }
+    };
+  }, []);
+
+  useEffect(() => {
+    checkLineNumberWidth();
+  }, [value]);
+
+  useResizeObserver({
+    ref: rootRef,
+    onResize: checkLineNumberWidth,
+  });
+
   return (
-    <div className={clsx(classes.root, className)}>
+    <div className={clsx(classes.root, className)} ref={rootRef}>
       {labelText && <FormLabel id={id}>{labelText}</FormLabel>}
 
-      <div className={clsx(classes.wrapper, { [classes.invalid]: invalid })}>
+      <div
+        className={clsx(classes.wrapper, { [classes.invalid]: invalid })}
+        style={
+          { [`--line-number-width`]: `${lineNumberWidth}px` } as CSSProperties
+        }
+      >
         <SyntaxHighlighter
+          PreTag={PreTag}
           language="python"
           style={style}
-          // TODO: resolve text wrapping
-          // showLineNumbers={showLineNumbers}
+          showLineNumbers={showLineNumbers}
         >
           {value.at(-1) === '\n' ? `${value} ` : value}
         </SyntaxHighlighter>
@@ -153,6 +225,7 @@ export function EditableSyntaxHighlighter({
         {!readOnly && (
           <textarea
             {...props}
+            ref={textAreaRef}
             id={id}
             className={classes.textarea}
             value={value}
diff --git a/src/modules/apps/builder/SourceCodeEditor.module.scss b/src/modules/apps/builder/SourceCodeEditor.module.scss
index 29ff512..90e74cb 100644
--- a/src/modules/apps/builder/SourceCodeEditor.module.scss
+++ b/src/modules/apps/builder/SourceCodeEditor.module.scss
@@ -27,7 +27,7 @@
   block-size: 100%;
   inline-size: 100%;
   overflow-y: auto;
-  padding-block-end: $spacing-08;
+  padding-block-end: $spacing-10;
   background-color: $layer-02;
 
   > div {
diff --git a/src/modules/apps/builder/SourceCodeEditor.tsx b/src/modules/apps/builder/SourceCodeEditor.tsx
index 46b2bf7..3702920 100644
--- a/src/modules/apps/builder/SourceCodeEditor.tsx
+++ b/src/modules/apps/builder/SourceCodeEditor.tsx
@@ -15,11 +15,11 @@
  */
 
 import { EditableSyntaxHighlighter } from '@/components/EditableSyntaxHighlighter/EditableSyntaxHighlighter';
-import classes from './SourceCodeEditor.module.scss';
+import { useChat } from '@/modules/chat/providers/chat-context';
+import { Button } from '@carbon/react';
 import { useEffect, useId, useRef, useState } from 'react';
 import { useAppBuilder, useAppBuilderApi } from './AppBuilderProvider';
-import { Button } from '@carbon/react';
-import { useChat } from '@/modules/chat/providers/chat-context';
+import classes from './SourceCodeEditor.module.scss';
 
 interface Props {
   onSaveCode: () => void;
@@ -52,6 +52,7 @@ export function SourceCodeEditor({ onSaveCode }: Props) {
           required
           rows={16}
           readOnly={status === 'fetching'}
+          showLineNumbers
         />
       </div>
       <div className={classes.buttons}>
diff --git a/src/modules/tools/manage/UserToolModal.tsx b/src/modules/tools/manage/UserToolModal.tsx
index daed0cd..75dbbb6 100644
--- a/src/modules/tools/manage/UserToolModal.tsx
+++ b/src/modules/tools/manage/UserToolModal.tsx
@@ -277,6 +277,7 @@ export function UserToolModal({
                             invalid={errors.api?.schema != null}
                             rows={16}
                             className={classes.apiSchemaField}
+                            showLineNumbers
                           />
                         </>
                       )}
@@ -309,6 +310,7 @@ export function UserToolModal({
                         required
                         invalid={errors.sourceCode != null}
                         rows={16}
+                        showLineNumbers
                       />
                     )}
                   />
@@ -469,6 +471,7 @@ UserToolModal.View = function ViewUserToolModal({
           readOnly
           rows={16}
           className={type === 'api' ? classes.apiSchemaField : undefined}
+          showLineNumbers
         />
       </ModalBody>
     </Modal>