JSON to Java POJO
Paste JSON and get Java classes with Lombok, getters and setters, or Java 17 records, plus Jackson annotations. Private, in your browser.
Paste JSON on the left. Add a second sample to find optional fields.
JSON input
Stays in your browserJava code
Shortcuts: Ctrl+Enter run · Ctrl+Shift+C copy result · / search (use ⌘ on Mac)
Next steps
Need the same types in another language? JSON to TypeScript, JSON to Go Struct, JSON to Rust Struct, JSON to C# Class, JSON to Python Dataclass, JSON to Dart Class. Or validate a document against a JSON Schema.
Free Online JSON to Java POJO Generator
Generate Java classes from a JSON sample so Jackson can read it without hand-written boilerplate. It gives developers a quick browser-based way to solve a focused json to java pojo task before moving the result into a project.
How to generate Java code from JSON
Paste a JSON object or an array of objects into the input box and press Generate. Pick Lombok @Data, plain getters and setters, or a Java 17 record. Jackson @JsonProperty is added only where the JSON key differs from the Java name.
One input, every language
Your JSON stays in the box when you switch the language tabs, and the code is generated again at once. Each language also has its own page, so you can bookmark the one you use.
How types are worked out
- Whole numbers and numbers with decimals are told apart.
- Add more samples with Add sample: a key missing from some samples becomes optional, and null makes a type nullable.
- Arrays of objects are merged into one type, and nested objects become their own types named after the key.
- Keys that are not valid names in the language (such as first-name or 2fa) are renamed and mapped back, never rejected.
Worked example
The sample JSON in the box above, generated with the default options:
{
"id": 1,
"name": "Ada",
"email": null,
"tags": ["x"],
"address": { "city": "Pune", "pin": "411001" },
"createdAt": "2026-01-15T10:30:00Z"
}import java.util.List;
import lombok.Data;
@Data
public class Root {
private long id;
private String name;
private String email;
private List<String> tags;
private Address address;
private String createdAt;
}
@Data
public class Address {
private String city;
private String pin;
}
Common mistakes
- A single sample cannot show which fields are optional. Paste two or three different responses for a realistic result.
- A value that is always null gives no type information, so it is treated as a nullable string. Change it by hand if it is something else.
- Numbers are typed from the samples: 1 and 1.0 look the same in JSON, so use a sample with decimals where you need a float.