JMESPath · lesson 1 of 15 · Basics

Identifiers & missing values

A JMESPath expression is a path: office.city reads city inside office, with no leading . or $. A key that doesn't exist is not an error — the result is null.

Example 1A sub-expression

Document

{
  "team": "Platform",
  "office": { "city": "Berlin", "floor": 3 },
  "members": [
    { "name": "Ada", "age": 36, "role": "lead", "active": true,
      "email": "[email protected]", "skills": ["rust", "sql"] },
    { "name": "Linus", "age": 28, "role": "dev", "active": true,
      "email": null, "skills": ["c", "shell"] },
    { "name": "Grace", "age": 45, "role": "dev", "active": false,
      "skills": ["cobol"] },
    { "name": "Alan", "age": 41, "role": "qa", "active": true,
      "email": "[email protected]", "skills": [] }
  ]
}

Query

office.city

office A top-level key.
.city A sub-expression: the city key of that object → "Berlin".

Result

"Berlin"

Try it in the playground

Example 2A missing key

Document

{
  "team": "Platform",
  "office": { "city": "Berlin", "floor": 3 },
  "members": [
    { "name": "Ada", "age": 36, "role": "lead", "active": true,
      "email": "[email protected]", "skills": ["rust", "sql"] },
    { "name": "Linus", "age": 28, "role": "dev", "active": true,
      "email": null, "skills": ["c", "shell"] },
    { "name": "Grace", "age": 45, "role": "dev", "active": false,
      "skills": ["cobol"] },
    { "name": "Alan", "age": 41, "role": "qa", "active": true,
      "email": "[email protected]", "skills": [] }
  ]
}

Query

office.nope

nope A key that doesn't exist evaluates to null — it is not an error.

Result

null

Try it in the playground

Good to know

In the playground, pick JMESPath with the buttons above the query: a plain path like office.city is otherwise auto-detected as jq. Try it does this for you.
Keys with spaces or symbols go in double quotes: "first name".