diff --git a/app/src/analyzers/conventionExtractor.ts b/app/src/analyzers/conventionExtractor.ts
new file mode 100644
index 0000000..6c4a6e0
--- /dev/null
+++ b/app/src/analyzers/conventionExtractor.ts
@@ -0,0 +1,251 @@
+import * as fs from 'fs';
+import * as path from 'path';
+import { CodingConventions, FileNamingConvention } from '../types';
+import { readFileContent, globFiles } from '../utils/fileUtils';
+
+const TEST_FRAMEWORKS: Record<string, string> = {
+  jest: 'jest',
+  'jest-environment-jsdom': 'jest',
+  vitest: 'vitest',
+  mocha: 'mocha',
+  chai: 'mocha',
+  pytest: 'pytest',
+  'pytest-cov': 'pytest',
+  unittest: 'unittest',
+  nose: 'nose',
+  'testing-library/jest-dom': 'jest',
+  'testing-library/react': 'jest',
+  '@testing-library/jest-dom': 'jest',
+  '@testing-library/react': 'jest'
+};
+
+export async function extractConventions(
+  directory: string,
+  projectType: string
+): Promise<CodingConventions> {
+  const files = await globFiles(
+    ['**/*.{ts,js,tsx,jsx,py,go,rs,java}'],
+    directory,
+    ['node_modules/**', 'dist/**', 'build/**', '.git/**']
+  );
+
+  const fileNamingConventions = detectFileNamingConvention(files);
+  const importStyle = detectImportStyle(files);
+  const testingFramework = detectTestingFramework(directory, files);
+
+  return {
+    fileNamingConvention: fileNamingConventions,
+    importStyle,
+    testingFramework: testingFramework?.framework,
+    testingStyle: testingFramework?.style || null,
+    componentStyle: detectComponentStyle(files, projectType),
+    modulePattern: detectModulePattern(files, projectType)
+  };
+}
+
+function detectFileNamingConvention(files: string[]): FileNamingConvention {
+  const sampleSize = Math.min(files.length, 50);
+  const samples = files.slice(0, sampleSize);
+  
+  const scores: Record<string, number> = {
+    camelCase: 0,
+    snake_case: 0,
+    PascalCase: 0,
+    'kebab-case': 0
+  };
+
+  for (const file of samples) {
+    const filename = path.basename(file, path.extname(file));
+    
+    if (/^[a-z]+([A-Z][a-z0-9]*)*$/.test(filename)) {
+      scores.camelCase++;
+    } else if (/^[a-z]+(_[a-z0-9]+)*$/.test(filename)) {
+      scores.snake_case++;
+    } else if (/^[A-Z][a-zA-Z0-9]*$/.test(filename)) {
+      scores.PascalCase++;
+    } else if (/^[a-z]+(-[a-z0-9]+)*$/.test(filename)) {
+      scores['kebab-case']++;
+    }
+  }
+
+  const maxScore = Math.max(...Object.values(scores));
+  
+  if (maxScore === 0) {
+    return 'unknown';
+  }
+
+  const bestMatch = Object.entries(scores).find(([_, score]) => score === maxScore);
+  return (bestMatch?.[0] as FileNamingConvention) || 'unknown';
+}
+
+function detectImportStyle(files: string[]): CodingConventions['importStyle'] {
+  const sampleSize = Math.min(files.length, 30);
+  const samples = files.slice(0, sampleSize);
+  
+  let es6Imports = 0;
+  let commonjsImports = 0;
+  let relativeImports = 0;
+  let pythonImports = 0;
+  let goImports = 0;
+
+  for (const file of samples) {
+    const content = readFileContent(file);
+    if (!content) continue;
+
+    const ext = path.extname(file);
+
+    if (['.ts', '.js', '.tsx', '.jsx'].includes(ext)) {
+      if (/\bimport\s+.*\s+from\s+['"]/.test(content)) {
+        es6Imports++;
+      }
+      if (/\brequire\s*\(\s*['"]/.test(content)) {
+        commonjsImports++;
+      }
+      if (/from\s+['"]\.?[\/'"].test(content)) {
+        relativeImports++;
+      }
+    } else if (ext === '.py') {
+      if (/\bimport\s+\w+/.test(content) || /\bfrom\s+\w+/.test(content)) {
+        pythonImports++;
+      }
+    } else if (ext === '.go') {
+      if (/\bimport\s*\(/m.test(content) || /\bimport\s+["']/.test(content)) {
+        goImports++;
+      }
+    }
+  }
+
+  if (pythonImports > 0) {
+    return 'python';
+  } else if (goImports > 0) {
+    return 'go';
+  } else if (es6Imports > commonjsImports && es6Imports > relativeImports) {
+    return 'es6';
+  } else if (commonjsImports > relativeImports) {
+    return 'commonjs';
+  } else if (relativeImports > es6Imports + commonjsImports) {
+    return 'relative';
+  } else if (es6Imports > 0 || commonjsImports > 0) {
+    return 'mixed';
+  }
+
+  return 'es6';
+}
+
+function detectTestingFramework(
+  directory: string,
+  files: string[]
+): { framework: string; style: CodingConventions['testingStyle'] } | null {
+  const packageJsonPath = path.join(directory, 'package.json');
+  
+  const packageJson = fs.existsSync(packageJsonPath)
+    ? JSON.parse(fs.readFileSync(packageJsonPath, 'utf-8'))
+    : null;
+  
+  const allDeps = {
+    ...(packageJson?.dependencies || {}),
+    ...(packageJson?.devDependencies || {})
+  };
+
+  for (const [pkg, framework] of Object.entries(TEST_FRAMEWORKS)) {
+    if (allDeps[pkg]) {
+      const styleMap: Record<string, CodingConventions['testingStyle']> = {
+        jest: 'jest',
+        vitest: 'vitest',
+        mocha: 'mocha',
+        pytest: 'pytest',
+        unittest: 'unittest',
+        testing: 'testing'
+      };
+      return { framework: pkg, style: styleMap[framework] || null };
+    }
+  }
+
+  for (const file of files) {
+    const basename = path.basename(file);
+    
+    if (basename.includes('.test.') || basename.includes('.spec.')) {
+      return { framework: 'test runner', style: 'jest' };
+    }
+    
+    if (basename.startsWith('test_') || basename.endsWith('_test.py')) {
+      return { framework: 'pytest', style: 'pytest' };
+    }
+  }
+
+  return null;
+}
+
+function detectComponentStyle(files: string[], _projectType: string): CodingConventions['componentStyle'] {
+  const tsxFiles = files.filter(f => f.endsWith('.tsx'));
+  
+  if (tsxFiles.length === 0) {
+    return null;
+  }
+
+  const sampleSize = Math.min(tsxFiles.length, 20);
+  const samples = tsxFiles.slice(0, sampleSize);
+  
+  let functional = 0;
+  let classBased = 0;
+  let hooks = 0;
+
+  for (const file of samples) {
+    const content = readFileContent(file);
+    if (!content) continue;
+
+    if (/\bfunction\s+\w+\s*\(/.test(content)) {
+      functional++;
+    }
+    if (/\bclass\s+\w+\s+extends\s+(React\.)?Component/.test(content)) {
+      classBased++;
+    }
+    if (/\buse\w+\s*\(/.test(content)) {
+      hooks++;
+    }
+  }
+
+  if (hooks > functional + classBased) {
+    return 'hooks';
+  } else if (functional > classBased) {
+    return 'functional';
+  } else if (classBased > 0) {
+    return 'class';
+  }
+
+  return 'functional';
+}
+
+function detectModulePattern(files: string[], _projectType: string): CodingConventions['modulePattern'] {
+  const sampleSize = Math.min(files.length, 30);
+  const samples = files.slice(0, sampleSize);
+  
+  let defaultExports = 0;
+  let namedExports = 0;
+  let wildcardImports = 0;
+
+  for (const file of samples) {
+    const content = readFileContent(file);
+    if (!content) continue;
+
+    if (/export\s+default/.test(content)) {
+      defaultExports++;
+    }
+    if (/export\s+{/.test(content)) {
+      namedExports++;
+    }
+    if (/import\s+\*\s+as/.test(content)) {
+      wildcardImports++;
+    }
+  }
+
+  if (defaultExports > namedExports && defaultExports > wildcardImports) {
+    return 'default';
+  } else if (namedExports > defaultExports && namedExports > wildcardImports) {
+    return 'named';
+  } else if (wildcardImports > defaultExports + namedExports) {
+    return 'wildcard';
+  }
+
+  return 'default';
+}