How to Fix Missing Turkish Characters in Dompdf Output

Use a Unicode TrueType font and make the entire input path UTF-8. In Dompdf, set DejaVu Sans as the default and in CSS, declare <meta charset="UTF-8">, and call loadHtml($html, 'UTF-8'). This covers ğ, Ğ, ş, Ş, İ, ı, ö, Ö, ü, Ü, ç and Ç.

Dompdf’s core PDF fonts (Helvetica, Times, Courier and generic families) use Windows ANSI coverage, so a browser rendering correctly does not prove that the PDF font contains Turkish glyphs. Dompdf bundles DejaVu TrueType fonts for broad Unicode coverage. See the Dompdf documentation and its Unicode guide.

1. Apply the reliable fix

Install Dompdf with Composer if it is not already in your application:

composer require dompdf/dompdf

Then render a literal diagnostic string before adding database data or templates:

<?php
require __DIR__ . '/vendor/autoload.php';

use Dompdf\Dompdf;
use Dompdf\Options;

$options = new Options();
$options->set('defaultFont', 'DejaVu Sans');
$dompdf = new Dompdf($options);

$html = <<<'HTML'
<!doctype html>
<html lang="tr">
<head>
  <meta charset="UTF-8">
  <style>
    body { font-family: "DejaVu Sans", sans-serif; }
  </style>
</head>
<body>
  <h1>Türkçe PDF testi</h1>
  <p>Türkçe karakterler: ğ, Ğ, ş, Ş, İ, ı, ö, Ö, ü, Ü, ç, Ç.</p>
</body>
</html>
HTML;

$dompdf->loadHtml($html, 'UTF-8');
$dompdf->setPaper('A4', 'portrait');
$dompdf->render();
$dompdf->stream('turkish-test.pdf', ['Attachment' => false]);

The explicit default and CSS declarations make font selection deterministic. The explicit encoding argument is appropriate when the PHP string is UTF-8; Dompdf also reads a BOM and meta declarations and can normalize non-UTF-8 input with mb_convert_encoding.

2. Verify encoding before Dompdf

1. Save PHP source and template files as UTF-8 (preferably without a legacy editor conversion).
2. Keep <meta charset="UTF-8"> in the HTML sent to Dompdf.
3. Confirm your database connection uses UTF-8 (for MySQL, use utf8mb4 at the connection and schema layers).
4. Inspect the raw PHP value before rendering. A browser can hide an upstream conversion error; log the byte sequence or use mb_check_encoding($value, 'UTF-8').
5. Pass the known encoding to loadHtml and render the literal test string in the same template that fails.

$value = $row['name'];
if (!mb_check_encoding($value, 'UTF-8')) {
    throw new RuntimeException('Input is not valid UTF-8');
}
$dompdf->loadHtml($html, 'UTF-8');

3. Use a custom Turkish font when branding requires it

Use a readable TrueType (.ttf) file containing every glyph in the document. Register it with CSS and retain DejaVu as a fallback:

@font-face {
  font-family: 'Brand Turkish';
  src: url('fonts/BrandTurkish-Regular.ttf') format('truetype');
  font-style: normal;
  font-weight: 400;
}
body {
  font-family: 'Brand Turkish', 'DejaVu Sans', sans-serif;
}

The font path must be inside Dompdf’s allowed file scope (including its chroot rules) and readable by the PHP process. The font cache directory must be writable while Dompdf prepares metrics. Supply separate regular, bold and italic files when those weights are used; otherwise a missing variant can fall back unexpectedly. Clear stale generated metrics after replacing a font.

DejaVu Sans or a custom font?

Choice	Use it when	Check
DejaVu Sans	You need a low-friction Unicode baseline	Glyphs render in the diagnostic string
Custom TrueType	Your visual identity requires a specific typeface	All Turkish glyphs, variants, path access and cache writes work

4. Diagnose boxes, question marks and missing accents

1. Literal test. Put Türkçe: ğ Ğ ş Ş İ ı ö Ö ü Ü ç Ç directly in the failing template. If it fails, the font or encoding setup is wrong.
2. Font isolation. Temporarily remove Arial, Helvetica, Times, Courier and generic-only declarations. Set font-family: "DejaVu Sans" directly.
3. Input inspection. Check the PHP string and database bytes before Dompdf. Repair conversion at the boundary instead of replacing characters after rendering.
4. Extension check. Install PHP’s mbstring extension. Dompdf lists it as a requirement and uses it when normalizing non-UTF-8 input.
5. Custom font access. Verify the exact case-sensitive path, file permissions, chroot/allowed path and readable TTF file.
6. Cache reset. Remove stale generated font metrics after changing a font, then render again with a writable cache.
7. Inspect the PDF itself. If HTML looks correct in a browser but the PDF does not, the remaining fault is usually PDF font selection or font-file accessibility.

5. Common errors and fixes

Symptom	Likely cause	Fix
ğ or ş becomes a box/question mark	Core ANSI font selected	Set DejaVu Sans or a Unicode TTF in CSS and options
Every accented character is corrupted	Input is not UTF-8	Fix file/database encoding; validate with mb_check_encoding; pass UTF-8 to loadHtml
Custom font silently falls back	Path, chroot or permissions block access	Use an allowed readable path and inspect PHP process permissions
First render works, later renders fail	Font cache is stale or not writable	Clear generated metrics and grant cache write access
Bold Turkish text is missing	No bold face was supplied	Register a TTF for each weight/style used
mb_convert_encoding is unavailable	mbstring is not installed	Install/enable mbstring, then restart the PHP runtime

6. Production checklist

• Use UTF-8 from source file through database, PHP string and HTML.
• Declare the charset and call loadHtml($html, 'UTF-8').
• Choose DejaVu Sans explicitly, or verify every custom TTF glyph.
• Keep font files within allowed paths and readable by PHP.
• Make the font cache writable and clear metrics after font changes.
• Render a Turkish fixture in CI or a release smoke check and inspect the generated PDF.

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FAQ

Why does Chrome show Turkish text correctly?

Chrome and Dompdf may choose different fonts. Browser success does not prove the PDF font contains the glyphs.

Can I keep Arial?

Only if you provide and register a Unicode TrueType version that contains every glyph you use. For diagnosis, switch directly to DejaVu Sans.

Do I need to convert Turkish text manually?

No. Preserve valid UTF-8 end to end. Convert only at an input boundary when you have confirmed the source encoding.

Why are only bold or italic letters broken?

Dompdf may be resolving a separate face. Register readable TTF files for each weight and style used.