iText's software libraries are quite technical and the world of PDF comes with its own professional jargon. If you're feeling mystified by some of the PDF vocabulary, you've come to the right place to learn more. In case you can't seem to find a term or if you think you could offer an even better explanation, let us know! We'll be happy to hear from you. In case you're looking for more content to sate your hunger, please check out the buttons under the picture.




Application programming interface, a set of definitions and protocols for using external software to build software applications. A good API helps programmers make their work easier and more efficient.


Decreasing reliance on physical objects for workflow processes and documentation (e.g. cloud services, OCR and paperless office).

Digital transformation

Moving processes and business from the offline to the online space, automating manual tasks and letting digital technologies meaningfully contribute to overall efficiency and business strategies.


The smallest graphical unit to represent a character or part of a character (e.g. the many ways of rendering the character ‘a’ are all different glyphs that represent the same character).

Hash and hashing

Several meanings are possible but in iText terminology, we talk about a data derivation method and way of assuring users that their documents have not been altered since they last opened them. This is important for applications such as digital signatures and authentication


Programming term that describes operations that contain several other operations, comparable to a shortcut that does many things for you automatically.


Integrated development environment, a generic term for the program programmers use to program (e.g. Eclipse, Visual Studio).


Uneven spacing between glyphs in certain font to make the text flow better.


In software terms, one or more packages of code, sometimes used interchangeably with the term SDK (e.g. in Microsoft environments, a DLL-file is a library).


Two or more graphemes joined in a single glyph (e.g. “æ”).


Programming term that describes very detailed, minute operations.


data that usually gets appended to your document (e.g. authorship, keywords) and is always “data about the data”.


Optical character recognition (e.g. when a scanner recognizes characters from a paper document and converts them to the right glyphs).


“PDF Advanced Electronic Signatures”, an ETSI standard for digital signatures.


Portable Document Format.


ISO-standard PDF format optimized for archiving.


ISO-standard PDF format optimized for engineering, manufacturing and construction.


ISO-standard PDF format optimized for universal accessibility, intended mostly for people with visual impairments who use assistive technology to read.


ISO-standard PDF format optimized for physical printing.


“Reading & Updating PDF Syntax”, an iText 5 solution that has been superseded by pdfDebug.


Software developer kit, basically packages of code developers can use in their projects.

Screen reader

Voice technology that reads out content to the user.


A typographical flourish for aesthetic reasons (e.g. titling).


XML Forms Architecture, static or dynamic, that iText can help flatten.


Extensible markup language, can be contained within a PDF to offer non-human readers a source of important information (e.g. for automated document processes in digital invoices).


“Zentraler User Guide des Forums elektronische Rechnung Deutschland” (“Central User Guide from the Electronic Invoice Forums of Germany”), a PDF specification that allows invoices to be processed by both human users and software.