jaq

jaq is a free data-processing tool for people who want jq-style queries in command-line workflows or Rust applications. It is particularly useful when work spans several structured formats, but workloads involving untrusted input need safeguards outside jaq.

Overview

jaq aims to make jq-style filtering correct, fast, and simple. It combines a command-line replacement for jq with a Rust library that compiles and runs jq programs, making it relevant both to shell users and developers embedding filters in software.

Key features

Beyond JSON, jaq supports YAML, CBOR, TOML, XML, CSV, and TSV. It can convert between those formats while applying a jq filter, reducing the need to split conversion and transformation across separate steps. This breadth is valuable for mixed-format pipelines; users needing only JSON have less reason to choose it over a dedicated viewer or editor.

For Rust applications, jaq-core can run in multithreaded environments and supports data types beyond JSON. jaq also allows arbitrary values as object keys and handles strings containing arbitrary bytes, including invalid UTF-8. These are useful capabilities when data does not fit ordinary JSON assumptions.

The project publishes comparisons with jq and gojq and reports faster results on many benchmarks. That makes jaq worth considering for performance-sensitive work, though it does not establish that every workload will run faster.

Platforms

Binary downloads are provided for Linux, Mac, and Windows, with installation instructions for Homebrew and Cargo. An online playground offers a way to try jaq, while the Rust library suits developers integrating it into their own applications.

Who it's for

jaq is a strong fit for developers and command-line users who already value jq-style filters and need to work across formats. Rust developers can also use it as a library, particularly when multithreaded use or non-JSON data types matter. For untrusted or costly workloads, it is not a safe standalone choice without external resource controls.

Pricing

jaq — free: The MIT-licensed open-source offering includes both the command-line program and Rust library. There is no paid tier or trial to weigh against a free plan; its practical cost is the need to manage resource limits independently where exhaustion would be a concern.

Pros and cons

• Pros: One jq-style workflow covers JSON, YAML, CBOR, TOML, XML, CSV, and TSV, including conversion during filtering.
• Pros: The Rust library supports multithreaded use and data beyond JSON, while arbitrary object keys and byte strings accommodate unusual inputs.
• Pros: The project says jaq is memory-safe, and reports that two NLnet-funded audits of its core by Radically Open Security had their reported issues addressed.
• Cons: It does not limit time, memory, or stack consumption, so an input or filter can exhaust resources unless the surrounding environment imposes limits.
• Cons: Its broad format and library capabilities are less compelling for readers who only need a visual JSON editor or viewer.

Alternatives

JSON Tools is a broader category to explore if jaq's command-line and library focus is not the right fit.

• jq is the direct alternative for users who want a free, MIT-licensed jq tool with standalone binaries for Linux, macOS, and Windows, rather than jaq's stated focus on multiple formats and a Rust library.
• Dadroit JSON Viewer suits readers seeking a viewer with JSON-to-CSV or XML conversion: its free non-commercial plan opens files up to 50 MB, while its Standard plan costs $98 per y.
• BracketView is an option for readers who prefer a web-based workflow with limited free uploads, encrypted snapshots, AI actions, and webhook endpoints.
• jless is a free MIT-licensed command-line tool for macOS and Linux to consider as another terminal-based option.
• jidoujisho is a free option for readers looking for software on Android 7.0 or later.
• JSON Crack is a free, open-source online tool for readers who prefer a web or browser-extension option.
• JSON Editor is a free MIT-licensed JavaScript library for readers building a JSON editor that runs in a modern browser.
• JSON Forms is a free option for readers looking for JSON Forms with community support.

Verdict

Choose jaq if you want jq-style filtering across multiple data formats or need a Rust library for compiling and running jq programs. Its format coverage, flexible data handling, and free MIT-licensed code make a persuasive package for technical workflows. Look elsewhere, or add external limits, when untrusted inputs must be prevented from consuming unbounded time, memory, or stack space.