diff --git a/src/main/MonospaceFontConfig.js b/src/main/MonospaceFontConfig.js
new file mode 100644
index 0000000..f92c477
--- /dev/null
+++ b/src/main/MonospaceFontConfig.js
@@ -0,0 +1,44 @@
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+const { app } = require('electron');
+const { getActiveMonoFont, isLigaturesEnabled, FAMILY_BY_KEY } = require('./settings/monospaceSettings');
+
+const WEIGHT_BY_KEY = { 300: 'Light', 400: 'Regular', 500: 'Medium', 600: 'SemiBold', 700: 'Bold' };
+
+function getAppRoot() {
+  if (process.resourcesPath && fs.existsSync(path.join(process.resourcesPath, 'app.asar.unpacked'))) {
+    return process.resourcesPath;
+  }
+  return path.resolve(__dirname, '..', '..');
+}
+
+function getCandidatePaths(family, weight) {
+  const familyDir = family === 'Fira Code' ? 'FiraCode' : 'JetBrainsMono';
+  const weightName = WEIGHT_BY_KEY[weight] || 'Regular';
+  const filename = `${familyDir}-${weightName}.ttf`;
+
+  const candidates = [];
+  candidates.push(path.resolve(getAppRoot(), 'assets', 'fonts', filename));
+  const packagedRoot = process.resourcesPath || getAppRoot();
+  candidates.push(path.join(packagedRoot, 'app.asar.unpacked', 'assets', 'fonts', filename));
+  return candidates;
+}
+
+function getMonoFontTtfPath(familyKey, weight = 400) {
+  const family = FAMILY_BY_KEY[familyKey] || 'JetBrains Mono';
+  const candidates = getCandidatePaths(family, weight);
+  for (const p of candidates) {
+    if (fs.existsSync(p)) return p;
+  }
+  const filename = path.basename(candidates[candidates.length - 1]);
+  console.warn(`[MonospaceFontConfig] bundled font missing: ${filename}; falling back to system monospace`);
+  return null;
+}
+
+function ligaturesEnabled(settings) { return isLigaturesEnabled(settings); }
+
+function getActiveFamily(settings) { return getActiveMonoFont(settings); }
+
+module.exports = { getMonoFontTtfPath, ligaturesEnabled, getActiveFamily };
diff --git a/tests/monospace-font-config.test.js b/tests/monospace-font-config.test.js
new file mode 100644
index 0000000..5af8bc3
--- /dev/null
+++ b/tests/monospace-font-config.test.js
@@ -0,0 +1,45 @@
+jest.mock('electron', () => ({
+  app: { getPath: () => '/fake/userData' },
+}));
+jest.mock('fs', () => ({ existsSync: jest.fn(), statSync: jest.fn() }));
+
+const fs = require('fs');
+const MonospaceFontConfig = require('../src/main/MonospaceFontConfig');
+
+describe('MonospaceFontConfig', () => {
+  afterEach(() => { jest.clearAllMocks(); });
+
+  test('returns null when no file exists', () => {
+    fs.existsSync.mockReturnValue(false);
+    const p = MonospaceFontConfig.getMonoFontTtfPath('jetbrains-mono', 400);
+    expect(p).toBeNull();
+  });
+
+  test('returns dev repo path when dev file exists', () => {
+    fs.existsSync.mockImplementation((p) => !p.includes('app.asar.unpacked') && p.endsWith('JetBrainsMono-Regular.ttf'));
+    const p = MonospaceFontConfig.getMonoFontTtfPath('jetbrains-mono', 400);
+    expect(p).toMatch(/assets\/fonts\/JetBrainsMono-Regular\.ttf$/);
+  });
+
+  test('returns packaged asar.unpacked path when present and file exists', () => {
+    fs.existsSync.mockImplementation((p) => p.includes('app.asar.unpacked') && p.endsWith('FiraCode-Regular.ttf'));
+    const p = MonospaceFontConfig.getMonoFontTtfPath('fira-code', 400);
+    expect(p).toContain('app.asar.unpacked');
+    expect(p).toContain('FiraCode-Regular.ttf');
+  });
+
+  test('returns null and warns when file is missing', () => {
+    const warn = jest.spyOn(console, 'warn').mockImplementation(() => {});
+    fs.existsSync.mockReturnValue(false);
+    const p = MonospaceFontConfig.getMonoFontTtfPath('fira-code', 700);
+    expect(p).toBeNull();
+    expect(warn).toHaveBeenCalledWith(expect.stringMatching(/FiraCode-Bold\.ttf/));
+    warn.mockRestore();
+  });
+
+  test('ligaturesEnabled maps from settings', () => {
+    expect(MonospaceFontConfig.ligaturesEnabled({ monospaceLigatures: true })).toBe(true);
+    expect(MonospaceFontConfig.ligaturesEnabled({ monospaceLigatures: false })).toBe(false);
+    expect(MonospaceFontConfig.ligaturesEnabled({})).toBe(false);
+  });
+});