jless

jless is a focused terminal viewer for developers who need to inspect structured data during API work, debugging, or command-line operations. It is a strong fit for keyboard-oriented users on macOS and Linux; choose another tool when querying or transforming JSON is central to the job.

Overview

jless presents JSON as a pretty-printed, syntax-highlighted document that remains navigable as structures grow deep. Objects and arrays can be expanded or collapsed, and vim-inspired commands keep movement efficient for users already comfortable with modal keyboard controls. Data mode provides a streamlined view, while line mode shows formatted JSON when the exact layout matters.

Input can come from a file or standard input, including newline-delimited JSON, so it works naturally in pipelines and with API output that has not been saved. YAML is also supported through file-extension detection or the --yaml flag. Comments and anchors are omitted from YAML display, making jless appropriate for examining parsed structure rather than preserving every source annotation.

Key features

• Search: Full-text and regular-expression search helps locate keys or values in unfamiliar payloads. It accelerates investigation, but it does not extract, filter, or transform matches.
• Navigation: Expand and collapse nested data while retaining a clear view of hierarchy. Vim-style movement favors experienced terminal users over people seeking a mouse-driven interface.
• Paths and output: Commands can copy or print values, keys, and paths, including unescaped string contents. The documented jq-style path for the focused node is useful when handing a location to a separate jq command, although jless does not execute jq queries itself.
• Clipboard: System-clipboard commands make it practical to move a selected value or path into another command, editor, or ticket without manually retyping it.
• Input flexibility: Files, standard input, newline-delimited JSON, and YAML cover common inspection workflows without requiring conversion first.

Pricing

jless is free at no cost under the MIT License. There is no paid tier, trial period, seat charge, or usage quota to manage. That makes it suitable for individual developers and teams that want a repeatable command-line utility without procurement overhead, while the trade-off is that commercial support or hosted conveniences are not part of the offering.

Platforms

jless currently supports macOS and Linux. Installation options include Homebrew, MacPorts, Arch Linux, Void Linux, NetBSD, FreeBSD, Cargo, downloadable binaries, and building from Rust source. The project is delivered as a standalone Rust binary, which keeps deployment simple. Building clipboard access from source on Linux requires X11 libraries. Windows is not supported, so cross-platform teams will need another viewer on that platform. jless also has no configuration file yet, limiting persistent customization of its behavior.

Who it's for

Choose jless if you inspect external API responses, debug request payloads, or browse large JSON and YAML streams from a terminal. It suits developers who value keyboard navigation, searchable hierarchy, and quick copying of a node or its path. It is less suitable for analysts who need visual editing, for workflows that must retain YAML comments and anchors, or for anyone who needs built-in querying and transformation rather than inspection.

Pros and cons

Pros

• Free MIT-licensed software with no plan limits or renewal terms.
• Pretty-printing, syntax highlighting, folding, and vim-inspired navigation make nested data easier to read in a terminal.
• Regular-expression search and newline-delimited JSON support help with unfamiliar or streaming input.
• Copy and print commands expose values, keys, and paths, including jq-style paths for follow-up commands.
• Standalone binaries and multiple package-manager options simplify installation on supported systems.

Cons

• Only macOS and Linux are supported, excluding Windows installations.
• No configuration file means preferences cannot be saved persistently.
• YAML comments and anchors are not displayed, so source annotations disappear from the view.
• It is a viewer, not a jq-compatible query engine; extraction and transformation require another tool.
• Linux source builds need X11 libraries for clipboard functionality.

Alternatives

JSON Tools is the broader category to browse when you want to compare viewers and utilities. Pick jq instead when querying and transforming JSON matters more than an interactive viewer; it is free, MIT-licensed, and runs on Linux, macOS, Windows, web, and self-hosted setups. Dadroit JSON Viewer is the better choice for a graphical, multi-platform workflow, with a free non-commercial plan for files up to 50 MB and paid Standard licensing. Choose gojq for a free MIT-licensed CLI and Go library when you want jq-compatible processing in Go-oriented environments. BracketView suits users who prefer a web-based interface with encrypted snapshots and AI actions under its free tier. gron is worth considering for a dependency-free binary workflow across Linux, macOS, Windows, and FreeBSD. jaq is another free MIT-licensed command-line and Rust-library option for processing JSON. jidoujisho is an Android alternative, while JSON OS provides browser-based JSON editing and Markdown preview.

Verdict

jless is an excellent choice for macOS and Linux developers who want fast, keyboard-driven inspection of JSON or YAML in the terminal, especially when search, folding, and copyable paths are the priority. Look elsewhere if you need Windows support, saved configuration, preserved YAML annotations, or built-in querying and transformation.