What it does
fx is a terminal JSON viewer and processor. It opens a file or piped input in an interactive view, and it can transform data with JavaScript expressions. The tool handles line-delimited and concatenated JSON streams as well as single JSON values. Its interactive navigation is useful for inspecting a response or configuration file, while expressions can select and reshape data without writing a separate script.
Pipe a response or open a saved file with fx data.json to inspect its structure interactively. For a quick transformation, the official getting-started guide uses an expression such as:
fx data.json '.users.map(x => x.name)'
In expressions, x refers to the input value and a leading dot is shorthand for a property path. fx also supports streaming JSON values; use --slurp when a stream should be handled as one array. The terminal interface includes Vim-style navigation and a query command, so it can serve as both a viewer and a small transformation step in a pipeline.
fx is a command-line tool rather than a hosted JSON service. Its query expressions use JavaScript, which is a useful fit for developers who already know that language but differs from jq's filter syntax. The official site lists current builds and installation paths; this research did not run the tool.
Strengths
- Combines an interactive terminal viewer with JavaScript-based JSON transformations.
- Supports JSON streams as well as individual values, with a `--slurp` option for treating a stream as an array.
- The official site provides an up-to-date release history and installation instructions.
Watch out for
- Queries use JavaScript expressions rather than jq's filter language.
- The core workflow requires a terminal and a locally installed command-line tool.
Best for
- Inspecting nested JSON files or HTTP responses from a terminal.
- Selecting or transforming JSON values inside a shell pipeline.
- Exploring streams of JSON records interactively.
Sources
- fx official product site (Oct 26, 2026)
- fx getting started and workflow guide (Oct 26, 2026)
- antonmedv/fx official repository (Oct 26, 2026)
- fx MIT license (Oct 26, 2026)