File Formats
What Is a UDF File? The UYAP Document Format
UDF is the document format used in UYAP, the Turkish Ministry of Justice's judicial information system. We explain what is inside it, which program opens it and what survives a conversion to Word or PDF.
Author: Hemen Dönüştür Editör EkibiPublished: 8 min read
If you are a lawyer in Turkey, a party to a court case there, or you work for an organization that corresponds with Turkish courts, you have almost certainly received a file ending in .udf. Double-click it and most computers do not know what to do: Word will not open it and PDF viewers do not recognize it. UDF is the document format used in UYAP, the judicial information system of the Turkish Ministry of Justice, and it is common only within that ecosystem. This article explains what UDF is, what is inside a UDF file, how to open it and what to keep in mind when converting it to Word or PDF.
What is UDF?
UDF stands for "UYAP doküman formatı", the UYAP document format; the download link on UYAP's official website describes the program as the "UYAP document format (UDF) program". Documents in this format are created, opened and edited with UYAP Doküman Editörü (UYAP Document Editor, called "UYAP Editör" on the site), which the Ministry distributes free of charge. Petitions, minutes and official letters can be prepared in this editor and shared through UYAP.
Note that the abbreviation "UDF" is used elsewhere too; the Universal Disk Format for optical discs, for example, is also called UDF. This article covers UYAP documents only.
A short history of UYAP and UDF
UYAP is the information system that moves the work of the Ministry of Justice's central and provincial organization and of the judicial units into electronic form, and it is the e-justice part of Turkey's e-government transformation. According to the timeline on UYAP's official website, the UYAP I project started in 2001 with the Ministry's central organization; UYAP II, launched in 2003, covered the judicial units and provincial organization and reached all first-instance courts and public prosecutors' offices by 2007. UYAP's General Information page states that more than 70,000 e-signatures have been distributed to judges, prosecutors and staff and are in active use.
Because documents need to circulate within this system in a common format under the institution's own control, UYAP uses its own document format and editor. We could not find an official, publicly available document on when UDF was first introduced or on its version history, so we do not give dates. Nor could we find a detailed official technical specification. The technical information below is based on examining real UDF files and on how our converter reads and writes them.
What is inside a UDF file?
A UDF file is really a ZIP archive. Rename a copy to .zip, open it, and you will find a file called content.xml, which holds the document text and all of its formatting. The root element is <template>, with a format_id attribute giving the format version (the files we have examined and the ones we produce use 1.8). Inside are four main sections:
<template format_id="1.8">
<content><![CDATA[The full document text goes here...]]></content>
<properties>
<pageFormat mediaSizeName="1" leftMargin="70.87" rightMargin="70.87"
topMargin="56.69" bottomMargin="56.69" paperOrientation="1" />
</properties>
<elements resolver="hvl-default">
<paragraph Alignment="0">
<content startOffset="0" length="7" bold="true" />
</paragraph>
...
</elements>
<styles>
<style name="hvl-default" family="Times New Roman" size="12" />
</styles>
</template><content>: all of the document's text, headers and footers included, sits as plain text in a single CDATA block. This section works like a "text pool".<properties>: page layout settings such as paper size, orientation and margins. Margins are in points; 70.87 points is about 2.5 cm.<elements>: the document structure. Paragraphs (<paragraph>), tables (<table>,<row>,<cell>), the header (<header>) and the footer (<footer>) are defined here. Paragraphs carry alignment, indentation, line spacing, space before and after, and bulleted or numbered list information as attributes.<styles>: text styles such as font family, size, bold, italic, underline and color. Colors are stored as signed integers.
UDF's most distinctive feature is that text and formatting are kept apart. Each formatted run inside a paragraph does not contain text itself but points to a position in the text pool: startOffset gives the first character and length the number of characters. The example above says "the first 7 characters of the text are bold". Images can be embedded as base64 in the imageData attribute of an <image> element. References to Java Swing font objects in the style definitions of the files we produce point to the editor's Java-based heritage, and UYAP's download page notes that the build for older macOS versions requires a compatible Java installation.
This offset-based design has a practical consequence: shift the text pool in content.xml by even one character and every formatting range after it lands in the wrong place. That is why editing UDF files by hand is risky.
Where is UDF used?
- Courts and prosecutors' offices: correspondence, minutes and decisions produced and shared within UYAP.
- Lawyers: preparing petitions and documents for work carried out through the UYAP Lawyer Portal.
- Citizens: case documents accessed through the UYAP Citizen Portal or e-Devlet, Turkey's e-government gateway.
- Experts, mediators and institutions: documents sent and received through UYAP's dedicated portals.
Strengths and weaknesses
Strengths: it provides a common format within the UYAP ecosystem, and e-signature and mobile signature workflows run through UYAP Editör. Because it is built on open technologies such as ZIP and XML, its structure can be inspected and converted. Files are usually small.
Weaknesses: it is almost entirely unsupported outside Turkey and outside the UYAP ecosystem; Word, Google Docs and PDF viewers do not open it. With no detailed public specification, third-party support relies on reverse engineering. The offset-based structure is fragile under manual edits.
Which program opens a UDF file?
The official route is UYAP Editör. UYAP's download page offers builds for Windows (.exe and .msi), macOS (Intel and Apple Silicon) and Pardus and Debian-based Linux distributions, and the mobile app is listed on Google Play and the App Store as "UYAP Doküman Editör". According to the page, the latest version of the editor must be installed for e-signature and mobile signature operations. We recommend downloading it only from official sources such as uyap.gov.tr.
If you cannot install the editor, or you only need to read the document, converting the file into a format anyone can open is the most practical solution.
Common problems and how to fix them
My computer does not recognize the UDF file
Without UYAP Editör installed, the operating system does not associate .udf with any program. Install the editor or convert the file to PDF or Word. Opening it in a text editor such as Notepad does not help: the file is a compressed archive, so you will only see garbage.
"File is corrupt" or "not a valid UYAP document"
A valid UDF must be a ZIP archive containing content.xml. Partially downloaded files, attachments damaged in transit and other files renamed to .udf fail this check. Try downloading the file again from its source.
Formatting looks different in the editor
When text is copied over from Word, some formatting (complex tables, text boxes, special fonts) may have no exact UDF equivalent. Check the final version in the editor before sending it.
Tips for converting UDF files
On our converter, UDF files are uploaded to our server and deleted within 30 minutes. The file is first checked to be a real ZIP archive, then content.xml is read. The text pool is split according to each paragraph's offsets, and font, size, bold, italic, underline, strikethrough, subscript and superscript, color, alignment, indentation, line spacing, lists, tables, headers and footers and embedded images are carried over in document order. If the XML is unexpectedly malformed, it is read as plain text so that at least the text is recovered.
- UDF to PDF is the easiest way to share or print a document with someone who does not have UYAP Editör.
- UDF to Word suits editing a UYAP document, reusing it in another document or archiving it.
- UDF to TXT extracts only the plain text, for searching or moving it into another system.
- With Word to UDF, the document is first normalized with LibreOffice, then paragraphs, formatting, lists, tables, embedded images and the page margins from Word are mapped to the UDF structure. The generated file uses
format_id="1.8". - With PDF to UDF, the PDF is first turned into flowing text, so the limits of PDF to Word conversion (multi-column pages, complex tables, no text in scanned pages) apply here too.
An important note: our converter reads only the document content (content.xml) from the UDF archive. The PDF or Word file you get is a new file and carries no e-signature. If you need a legally valid signed document, rely on the original accessed through UYAP.
Frequently Asked Questions
How do I open a UDF file?
The official way is the free UYAP Editör, available from uyap.gov.tr. To read it without installing anything, convert it to PDF or Word and open it on any device.
Can I open a UDF file in Word?
Word does not open UDF directly. Convert the file to DOCX first; the converted document keeps the text, formatting, tables and images in editable form.
Is the e-signature kept when I convert UDF to PDF?
No. Conversion produces a new file, and that file carries no e-signature. Where a valid signature matters, use the original document in UYAP.
How do I upload my Word document to UYAP?
Open the document in UYAP Editör and save it as UDF, or use the Word to UDF converter. Before submitting, we recommend opening the file in UYAP Editör to check how it looks.
Is it safe to convert UDF files?
Judicial documents can contain personal data. On our converter, files are used only for the conversion and are deleted from the server within 30 minutes. You remain responsible for following the retention and sharing rules that apply to the document, especially professional confidentiality obligations.
