APV File

What are APV files and how to open them

Are you having problems opening an APV 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 APV files.

What is an APV file?

An .APV file is an API Viewer Database file.

API Viewer Database files store a precompiled collection of Windows API declarations, constants, types, and function signatures used by the ApiViewer software from ActiveVB. These files are produced by ApiViewer as part of its internal databases so that the program can quickly look up and display API syntax and metadata in several programming languages. The databases include entries for Windows API functions, Visual Basic constants, user-defined types, and declarations across languages such as C, MASM, .NET, VB, PowerBASIC, PureBASIC, PyxiaBASIC, LibertyBASIC, Borland Delphi, and others.

ApiViewer writes these files in its various versions (version 1.05, 2.00, and later) to provide up-to-date API information - far richer and more current than VB's built-in api viewer file - such as newer functions, constants, and types added by Windows SDKs. When ApiViewer runs, it reads these database files to populate its lookup interface and support syntax-conversion or translation of declarations into different supported languages.

The format begins with a fixed header, starting with the ASCII signature VBAPI at offset 0, followed by version and file-info fields. The header includes counts of items like number of Subs, Functions, Constants, Types, and Declarations, followed by arrays of strings: names and data (signatures) for each declaration category. The major versions ApiViewer 1.05 and 2.00 are explicitly recognized in the version field.

How to open APV files

Important: Different programs may use files with the APV file extension for different purposes, so unless you are sure which format your APV file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested two different APV openers which you will find listed below.

Last updated: August 18, 2026

Various apps that use files with this extension

These apps are known to open certain types of APV files. Remember, different programs may use APV 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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