FLL File

What are FLL files and how to open them

Are you having problems opening a FLL file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your FLL files.

What is a FLL file?

FLL files have multiple uses, and Visual FoxPro Dynamic Link Library is one of them. Read more about the other uses further down the page.

Visual FoxPro Dynamic Link Library

Files with the .fll extension are most commonly associated with the Visual FoxPro programming language. The FLL files contain dynamic link libraries, which contain code functions that are used by Visual FoxPro.

These files are similar to DLL files, but FLL files are used for the Visual FoxPro only.

How to open FLL files

We have identified one FLL opener that is compatible with this specific type of FLL file.

Programs that open Visual FoxPro Dynamic Link Library files

Last updated: August 6, 2026

All known file formats using extension .FLL

While Visual FoxPro Dynamic Link Library is a popular type of FLL-file, we know of 2 different uses of the .FLL file extension. Different software may use files with the same extension for different types of data.

TextPipe Filter List

The TextPipe Filter List file (.FLL) is a saved set of filter configurations used by the TextPipe program from DataMystic to automate text processing tasks. Users design filters inside TextPipe's graphical user interface, then store them together - including search/replace rules, restrictions (e.g. by lines, columns, file types), comments, input/output file lists and other settings - in a .FLL file to reuse or run in batch. The .FLL file is written by TextPipe when you choose "Save Filter List" and is read by TextPipe; it forms the core of repeatable workflows and command-line or scheduled executions.

When running from the command line, TextPipe accepts .FLL files via parameters like /filter or /F, using them to set up all the filters, file lists, and options as defined in the .FLL file before processing begins. All filters in a loaded .FLL file are activated or disabled per their saved state. The filter list file thus allows batch or automated operations without manual setup each time.

Inside a .FLL file, there is a binary header and embedded ASCII strings that identify the file as a TextPipe filter definition file. It contains byte signatures like "TPF0" near the start, "FilterList" and "Version" fields, plus readable segments such as "THIS IS A TEXTPIPE PRO FILTER FILE" and references to DataMystic's website. These signatures allow TextPipe (and file-type detectors) to recognize it.

FLL opener for Windows

We have identified one FLL opener that is compatible with this specific type of FLL file.

Various apps that use files with this extension

These apps are known to open certain types of FLL files. Remember, different programs may use FLL files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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