JMESPath Tester
Free online JMESPath tester. Ideal for AWS CLI --query and Azure CLI. 100% client-side.
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What is JMESPath Tester?
The JMESPath Tester is a free browser-based playground for the JMESPath query language. Paste any JSON document, type a query, and see the extracted result instantly. It supports the full grammar — identifiers, wildcards, slices, filters, multiselect lists and objects, pipes, and built-in functions — and reports syntax errors with the parser message so you can fix queries fast.
Key Benefits
- Debug AWS CLI --query and Azure CLI expressions before running them for real
- Learn JMESPath interactively with curated examples and instant feedback
- Keep sensitive JSON on your machine — nothing is uploaded
- Distinguish no-match null results from actual errors
Common Use Cases
- •Writing the --query argument for aws ec2 describe-instances style commands
- •Extracting fields from large API responses before piping them onward
- •Prototyping JMESPath expressions for boto3 or Terraform data sources
- •Teaching teammates JMESPath patterns with shareable example queries
How to Use the JMESPath Tester
- Paste your JSON: Paste or type the JSON document you want to query into the JSON Data box. The tool flags invalid JSON immediately so you fix the payload before debugging queries.
- Enter a JMESPath query: Type a query such as people[?age > `30`].name in the query field, or click one of the example chips to load a ready-made query with matching sample data.
- Read the result: The result pane shows the pretty-printed JSON output. A null result means the query matched nothing — a normal JMESPath behavior, not an error.
- Inspect matches and errors: The matched-values panel lists what the query selected with synthesized paths. If the query is malformed, the tool shows whether it is a syntax error or a runtime error with the parser message.
Key Features
- Runs the official JMESPath reference implementation fully in your browser
- Live result pane with pretty-printed JSON and a no-match null indicator
- Matched-values panel with synthesized paths for projection results
- Parse and runtime errors classified separately with parser messages
- Curated example queries covering filters, multiselect, and functions
- JSON validation feedback before you even run the query
Frequently Asked Questions
What is JMESPath used for?
JMESPath is a query language for JSON. It is best known as the engine behind the AWS CLI --query option and is also used by the Azure CLI, boto3, Kubernetes tools, and many data pipelines to extract and reshape JSON without writing custom code.
Does the tool send my JSON anywhere?
No. Everything runs in your browser using the JMESPath reference implementation bundled with the page. Your JSON and queries never leave your machine, so it is safe for internal or sensitive payloads.
Why did my query return null?
JMESPath returns null when an expression matches nothing, for example when a key does not exist or a filter excludes every element. Null is a normal no-match result, not an error. Check spelling, quoting (identifiers with special characters need double quotes), and your filter conditions.
Why do numbers in filters need backticks?
Raw literals in JMESPath are wrapped in backticks, so you write people[?age > `30`] rather than people[?age > 30]. The backticks tell the parser to treat 30 as the JSON number 30 instead of an identifier. Strings inside filters use single or double quotes.