json iterator

Fastest JSON parser ever

jsoniter (json-iterator) is fast and flexible JSON parser available in Java and Go. Good deal of the code is ported from dsljson, and jsonparser

Why jsoniter?

  • Jsoniter is the fastest JSON decoder & encoder. It could be up to 10x faster than normal parser, data binding included. Shameless self benchmark
  • Extremely flexible api. You can mix and match three different styles: bind-api, any-api or iterator-api. Checkout your api choices
  • Innovations like lazy parsing, dynamic class shadowing, trie-tree fields matching, see more on DZone.com

Show off

Here is a quick show off, for more complete report you can checkout the full benchmark with in-depth optimization to back the numbers up

This is java version, doing data binding


This is go version, doing data binding


Super flexible API

  • any-api: use Java like PHP, high performance by lazy parsing
  • iterator-api: read through the JSON just like iterating over a collection
  • bind-api: binding any kind of data structure. It can even bind to existing object

Here is a simple demo. Each line is a object, first element being the order id, second element being the order details

[1024, {"product_id": 100, "start": "beijing"}]
["1025", {"product_id": 101, "start": "shanghai"}]
// many many more lines

There are three things to notice

  • There are many lines, read them all in once will have memory issue
  • Some order id is int, some order id is string. This is very common when working with PHP.
  • The order details has many fields, need object binding

Amazingly, in 6 lines, we have all problems solved:

JsonIterator iter = JsonIterator.parse(input);
OrderDetails orderDetails = new OrderDetails();
while(iter.whatIsNext() != ValueType.INVALID) {
    Any order = iter.readAny();
    int orderId = order.toInt(0);
    String start = order.get(1).bindTo(orderDetails).start;
  • JsonIterator.parse take InputStream as input, parse everything in a streaming way
  • readAny returns an instance of Any. The parsing is lazily done when actually getting the field, simple and performant.
  • bindTo(orderDetails), data binding can reuse existing object

Good old one line api is also available. To serialize

JsonStream.serialize(new int[]{1,2,3})

To deserialize

JsonIterator.deserialize("[1,2,3]", int[].class)

More on awsome apis

How to get

For java version


For Go version

go get github.com/json-iterator/go

Contribution Welcomed !

Report issue or pull request, or email [email protected], or Gitter chat