inja

inja is an open-source templating library for the C++ programming language, designed to render text templates by merging a template with a dynamic data model at runtime. Inspired by the Jinja2 template language, inja provides a familiar syntax for C++ developers to generate configuration files, source code, documentation, or other text outputs that depend on runtime data.

Templates in inja are parsed and evaluated against a context that can be supplied as JSON-like objects (maps and arrays) or as a JSON document. The templating syntax supports common features such as variable interpolation, attribute access, conditional statements, and loops. It also offers data transformation through filters and supports user-defined functions to extend functionality.

Usage typically involves loading a template from a string or a file, constructing a data context, and rendering the template to produce the final text. The library is designed to integrate with modern C++ codebases and to provide a lightweight and expressive means of generating text driven by data.

Inja is cross-platform and targets compilers that support at least C++11, with compatibility across major toolchains on Windows, macOS, and Linux. It is maintained as an open-source project and has been adopted in projects that require templated text generation without a separate runtime dependency.