About JMESPath Tester

Query JSON with JMESPath expressions + live result + examples. Part of the DevTools Surf developer suite. Browse more tools in the JSON collection.

Use Cases

• Extract specific fields from a large AWS CLI response
• Prototype filters before using them in Ansible or AWS CLI
• Learn JMESPath syntax by seeing live output
• Write event-filter expressions for CloudWatch or EventBridge

Tips

• Put the JMESPath expression on line 1 and JSON from line 2 onward
• Use users[*].name to project a field across an array
• Bracket indexes [0], [-1] are supported

Fun Facts

• JMESPath is used by the AWS CLI — every --query you've ever written is JMESPath syntax.
• JMESPath was created by James Saryerwinnie at Amazon and has official implementations in Python, Go, JavaScript, Java, PHP, Ruby, Lua, and Rust.
• Unlike JSONPath, JMESPath has a formal ABNF grammar specification, making it one of the few JSON query languages with deterministic behavior across implementations.

FAQ

Where is JMESPath used in practice?

AWS CLI's `--query` flag, Ansible filters, Azure CLI, Terraform providers, and many API client libraries. If you've used `aws ec2 describe-instances --query ...`, you've used JMESPath.

How do I filter a list of objects?

Use `[?property=='value']`. For example `Reservations[*].Instances[?State.Name=='running']` pulls running EC2 instances from a describe-instances response.

What's the difference between `|` and `.`?

`.` applies the next expression to each element in a projection; `|` stops the projection and applies the next expression to the whole result. Useful when you want to sort or slice the filtered list.

Does JMESPath support arithmetic?

Only through built-in functions (length, sum, avg, min_by, max_by, etc.). There are no infix math operators — JMESPath is a query language, not a calculator.