diff --git a/src/routes/__tests__/README.md b/src/routes/__tests__/README.md
new file mode 100644
index 0000000..a7e1b64
--- /dev/null
+++ b/src/routes/__tests__/README.md
@@ -0,0 +1,37 @@
+# Variant Route Tests
+
+This directory contains tests for the variant route normalization functionality.
+
+## Test Files
+
+- `test-utils.ts` - Shared utilities for testing range normalization
+- `variant.route.test.ts` - Unit tests for the `normalizeRange` function
+- `variant.route.integration.test.ts` - Integration test simulating the `/api/variant/all` endpoint
+
+## Running Tests
+
+These tests are meant to be run with `ts-node`. They are excluded from the TypeScript build process (see `tsconfig.json`).
+
+To run the tests:
+
+```bash
+# Install dependencies first
+yarn install
+
+# Run unit tests
+npx ts-node src/routes/__tests__/variant.route.test.ts
+
+# Run integration tests
+npx ts-node src/routes/__tests__/variant.route.integration.test.ts
+```
+
+## What the Tests Validate
+
+The tests ensure that the `normalizeRange` function correctly:
+- Handles empty strings
+- Handles null/undefined values
+- Handles whitespace-only strings
+- Handles invalid JSON
+- Handles malformed JSON (unclosed braces, etc.)
+- Passes through valid JSON unchanged
+- Always returns parseable JSON with `start` and `end` properties
diff --git a/src/routes/__tests__/test-utils.ts b/src/routes/__tests__/test-utils.ts
new file mode 100644
index 0000000..59d73a7
--- /dev/null
+++ b/src/routes/__tests__/test-utils.ts
@@ -0,0 +1,23 @@
+/**
+ * Test utilities for variant range normalization
+ */
+
+// Default range value for malformed/empty range strings
+export const DEFAULT_RANGE = '{"start":0,"end":0}';
+
+export function normalizeRange(range: string | null | undefined, variantId: string): string {
+  // Check if range is falsy or empty
+  if (!range || range.trim() === '') {
+    console.log(`[Variant API] Normalizing empty range for variant ${variantId} - using default range`);
+    return DEFAULT_RANGE;
+  }
+
+  // Try to parse the range to validate it's proper JSON
+  try {
+    JSON.parse(range);
+    return range; // Valid JSON, return as-is
+  } catch (error) {
+    console.log(`[Variant API] Normalizing invalid range for variant ${variantId} - using default range. Original value: "${range}"`);
+    return DEFAULT_RANGE;
+  }
+}
diff --git a/src/routes/__tests__/variant.route.integration.test.ts b/src/routes/__tests__/variant.route.integration.test.ts
new file mode 100644
index 0000000..d11510b
--- /dev/null
+++ b/src/routes/__tests__/variant.route.integration.test.ts
@@ -0,0 +1,58 @@
+/**
+ * Integration test to demonstrate the variant endpoint behavior
+ * This simulates what happens when the /api/variant/all endpoint is called
+ * Run with: npx ts-node src/routes/__tests__/variant.route.integration.test.ts
+ */
+
+import { DEFAULT_RANGE, normalizeRange } from './test-utils';
+
+// Simulate database response with various problematic range values
+const mockDatabaseVariants = [
+  { s_no: 'VAR-001', series: 'Series A', range: '{"start":10,"end":20}' },  // Valid
+  { s_no: 'VAR-002', series: 'Series B', range: '' },                        // Empty string
+  { s_no: 'VAR-003', series: 'Series C', range: null },                      // Null
+  { s_no: 'VAR-004', series: 'Series D', range: '   ' },                     // Whitespace
+  { s_no: 'VAR-005', series: 'Series E', range: '{invalid json}' },          // Invalid JSON
+  { s_no: 'VAR-006', series: 'Series F', range: '{"start":0' },              // Malformed JSON
+  { s_no: 'VAR-007', series: 'Series G', range: '{"start":0,"end":0}' },     // Default valid
+];
+
+console.log('=== Simulating /api/variant/all endpoint ===\n');
+
+// Simulate the endpoint logic
+console.log('Step 1: Fetching variants from database...');
+console.log(`Found ${mockDatabaseVariants.length} variants\n`);
+
+console.log('Step 2: Normalizing range values...');
+const normalizedVariants = mockDatabaseVariants.map(variant => ({
+  ...variant,
+  range: normalizeRange(variant.range as any, variant.s_no)
+}));
+
+console.log('\nStep 3: Preparing response...');
+const response = { variants: normalizedVariants };
+
+console.log('\n=== Final API Response ===');
+console.log(JSON.stringify(response, null, 2));
+
+console.log('\n=== Verification ===');
+let allRangesParseable = true;
+response.variants.forEach(variant => {
+  try {
+    const parsed = JSON.parse(variant.range);
+    console.log(`✓ ${variant.s_no}: range is parseable JSON with start=${parsed.start}, end=${parsed.end}`);
+  } catch (error) {
+    console.error(`✗ ${variant.s_no}: range is NOT parseable JSON: "${variant.range}"`);
+    allRangesParseable = false;
+  }
+});
+
+console.log('\n=== Result ===');
+if (allRangesParseable) {
+  console.log('✓ SUCCESS: All ranges are safe to parse!');
+  console.log('✓ The API will never return unparseable range values.');
+  process.exit(0);
+} else {
+  console.error('✗ FAILURE: Some ranges are not parseable!');
+  process.exit(1);
+}
diff --git a/src/routes/__tests__/variant.route.test.ts b/src/routes/__tests__/variant.route.test.ts
new file mode 100644
index 0000000..14a165b
--- /dev/null
+++ b/src/routes/__tests__/variant.route.test.ts
@@ -0,0 +1,110 @@
+/**
+ * Simple test file to demonstrate variant range normalization
+ * Run with: npx ts-node src/routes/__tests__/variant.route.test.ts
+ */
+
+import { DEFAULT_RANGE, normalizeRange } from './test-utils';
+
+// Test cases
+console.log('=== Running Variant Range Normalization Tests ===\n');
+
+let testsPassed = 0;
+let testsFailed = 0;
+
+function test(description: string, fn: () => void) {
+  try {
+    fn();
+    console.log(`✓ ${description}`);
+    testsPassed++;
+  } catch (error) {
+    console.error(`✗ ${description}`);
+    console.error(`  Error: ${error}`);
+    testsFailed++;
+  }
+}
+
+function assertEqual(actual: any, expected: any, message?: string) {
+  if (actual !== expected) {
+    throw new Error(message || `Expected ${expected}, but got ${actual}`);
+  }
+}
+
+// Test 1: Valid JSON range should pass through unchanged
+test('Valid JSON range should pass through unchanged', () => {
+  const input = '{"start":10,"end":20}';
+  const result = normalizeRange(input, 'TEST-001');
+  assertEqual(result, input, 'Valid JSON should not be modified');
+});
+
+// Test 2: Empty string should be normalized to default
+test('Empty string should be normalized to default', () => {
+  const result = normalizeRange('', 'TEST-002');
+  assertEqual(result, DEFAULT_RANGE, 'Empty string should return default range');
+});
+
+// Test 3: Null value should be normalized to default
+test('Null value should be normalized to default', () => {
+  const result = normalizeRange(null, 'TEST-003');
+  assertEqual(result, DEFAULT_RANGE, 'Null value should return default range');
+});
+
+// Test 4: Undefined value should be normalized to default
+test('Undefined value should be normalized to default', () => {
+  const result = normalizeRange(undefined, 'TEST-004');
+  assertEqual(result, DEFAULT_RANGE, 'Undefined value should return default range');
+});
+
+// Test 5: Whitespace-only string should be normalized to default
+test('Whitespace-only string should be normalized to default', () => {
+  const result = normalizeRange('   ', 'TEST-005');
+  assertEqual(result, DEFAULT_RANGE, 'Whitespace string should return default range');
+});
+
+// Test 6: Invalid JSON should be normalized to default
+test('Invalid JSON should be normalized to default', () => {
+  const result = normalizeRange('{invalid json}', 'TEST-006');
+  assertEqual(result, DEFAULT_RANGE, 'Invalid JSON should return default range');
+});
+
+// Test 7: Malformed JSON (unclosed brace) should be normalized
+test('Malformed JSON (unclosed brace) should be normalized', () => {
+  const result = normalizeRange('{"start":0', 'TEST-007');
+  assertEqual(result, DEFAULT_RANGE, 'Malformed JSON should return default range');
+});
+
+// Test 8: Plain text should be normalized to default
+test('Plain text should be normalized to default', () => {
+  const result = normalizeRange('not json at all', 'TEST-008');
+  assertEqual(result, DEFAULT_RANGE, 'Plain text should return default range');
+});
+
+// Test 9: Default range string should pass through
+test('Default range string should pass through unchanged', () => {
+  const result = normalizeRange(DEFAULT_RANGE, 'TEST-009');
+  assertEqual(result, DEFAULT_RANGE, 'Default range should pass through unchanged');
+});
+
+// Test 10: Ensure normalized result is always parseable
+test('Normalized result should always be parseable JSON', () => {
+  const testCases = ['', null, undefined, 'bad', '{incomplete', '   '];
+  testCases.forEach((testCase, index) => {
+    const result = normalizeRange(testCase as any, `TEST-010-${index}`);
+    try {
+      const parsed = JSON.parse(result);
+      if (!parsed.hasOwnProperty('start') || !parsed.hasOwnProperty('end')) {
+        throw new Error('Parsed result does not have start and end properties');
+      }
+    } catch (error) {
+      throw new Error(`Result "${result}" is not parseable JSON: ${error}`);
+    }
+  });
+});
+
+console.log('\n=== Test Summary ===');
+console.log(`Passed: ${testsPassed}`);
+console.log(`Failed: ${testsFailed}`);
+console.log(`Total: ${testsPassed + testsFailed}`);
+
+if (testsFailed > 0) {
+  process.exit(1);
+}
diff --git a/src/routes/variant.route.ts b/src/routes/variant.route.ts
index 5ed2497..081f6cd 100644
--- a/src/routes/variant.route.ts
+++ b/src/routes/variant.route.ts
@@ -3,6 +3,31 @@ import { prisma } from "../../prisma";
 
 const variantRouter = Router();
 
+// Default range value for malformed/empty range strings
+const DEFAULT_RANGE = '{"start":0,"end":0}';
+
+/**
+ * Normalizes a range string to ensure it's valid JSON.
+ * If the range is empty, falsy, or invalid JSON, returns the default range.
+ * Logs when normalization occurs.
+ */
+function normalizeRange(range: string | null | undefined, variantId: string): string {
+  // Check if range is falsy or empty
+  if (!range || range.trim() === '') {
+    console.log(`[Variant API] Normalizing empty range for variant ${variantId} - using default range`);
+    return DEFAULT_RANGE;
+  }
+
+  // Try to parse the range to validate it's proper JSON
+  try {
+    JSON.parse(range);
+    return range; // Valid JSON, return as-is
+  } catch (error) {
+    console.log(`[Variant API] Normalizing invalid range for variant ${variantId} - using default range. Original value: "${range}"`);
+    return DEFAULT_RANGE;
+  }
+}
+
 // variantRouter.get("/:sid", async (req, res) => {
 //   const sid = req.params.sid;
 //   await prisma.variant
@@ -28,11 +53,18 @@ variantRouter.get("/all", async (req, res) => {
   const variants = await prisma.variant.findMany({
     select: {
       s_no: true,
-	  series: true,
-	  range: true,
+      series: true,
+      range: true,
     },
   });
-  res.send({ variants: variants });
+  
+  // Normalize range values to ensure they're always safe to parse
+  const normalizedVariants = variants.map(variant => ({
+    ...variant,
+    range: normalizeRange(variant.range, variant.s_no)
+  }));
+  
+  res.send({ variants: normalizedVariants });
 });
 
 export { variantRouter };
diff --git a/tsconfig.json b/tsconfig.json
index 06bd6d3..1cc3470 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -6,5 +6,9 @@
     "lib": ["esnext", "es2015", "dom"],
     "esModuleInterop": true,
     "resolveJsonModule": true
-  }
+  },
+  "exclude": [
+    "node_modules",
+    "**/__tests__/**"
+  ]
 }