hidekazu-konishi.com

JSONPath / JMESPath Query Tester Tool - Real-Time JSON Query Evaluator for AWS CLI --query

First Published: 2026-04-28
Last Updated: 2026-04-28

Features

• Two query languages, one UI: Switch between JMESPath (the language behind aws cli --query) and JSONPath (Goessner-style $..book[?(@.price < 10)]) without leaving the page.
• Real-time evaluation (200ms debounce): Edit either pane and see the result update automatically — no submit button required.
• AWS-flavored examples: Preloaded JMESPath snippets mirror common describe-instances and describe-volumes patterns, so you can prototype CLI --query flags safely offline.
• Inline error explanations: JSON parse errors show line/column. Query errors surface the parser message verbatim (e.g. SyntaxError: Unknown character: ?).
• Recent JSON history (last 5): The most recent JSON inputs are stored in localStorage on this device only and can be reloaded with one click.
• One-click JSON formatter: Re-stringify JSON with 2/4-space, tab, or minified output.
• Result copy with fallback: Uses the modern Clipboard API where available and falls back to document.execCommand('copy') for older browsers.
• Keyboard shortcut: Ctrl/Cmd+Enter in either input forces an immediate re-evaluation.
• Mobile friendly: Two-pane layout collapses to a single column below 768px.
• 100% offline-capable: Once loaded, both query libraries are self-hosted and the page keeps working without an internet connection.

How to Use

1. Pick a query language by clicking the JMESPath or JSONPath tab.
2. Paste your JSON into the JSON Input textarea, or load a built-in example from the dropdown.
3. Type your query expression. The result pane updates automatically.
4. Adjust the output indent (2/4 spaces, tab, or minified) to match your downstream tool.
5. Use Format JSON to pretty-print the input, Copy Result to grab the output, and Clear All to reset.
6. To re-use a previous JSON payload, pick it from Recent JSON inputs.

JMESPath vs JSONPath at a glance

• JMESPath is the query language used by the AWS CLI's --query flag, AWS SDKs (Boto3 paginators, waiters), Ansible, Azure CLI, and others. Strengths: pipes, multi-select hashes/lists, projections, and built-in functions like sort_by, length, map, max_by.
• JSONPath (Goessner-style, as implemented by jsonpath-plus) is closer to XPath. Strengths: recursive descent ($..), array slicing ([start:end:step]), and inline JS-like filter predicates (?(@.price < 10)).
• Use this tool to confirm a query produces the same shape your CLI / SDK will receive before pasting it into a script.

Important Notes

• This tool implements JMESPath via the reference jmespath library used by the AWS CLI; the grammar should match exactly. JSONPath is implemented via jsonpath-plus, which uses a safe (no eval) expression evaluator in the browser.
• Filter expressions in JMESPath need backticks for literals: users[?age > `30`], not users[?age > 30].
• JSONPath result is always an array of matches — even when only one element matches.
• Recent-history entries are kept in this browser's localStorage only; clearing site data or browsing in private mode removes them.
• This tool does not parse newline-delimited JSON (JSON Lines) — paste a single JSON document.
• For very large JSON (multi-MB), evaluation may briefly block the UI thread; consider trimming the input before running expensive queries.