3.1   Overview

JSON-RPC over HTTP is an extension to the JSON-RPC 1.2 specification.

3.2   Conventions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.

Since JSON-RPC uses JSON, it shares the same type system as JSON (see http://www.json.org or RFC 4627). Whenever this document refers to any JSON type, the first letter is always capitalized: Object, Array, String, Number, True, False, Null.

Clients are the origin of Request objects. Servers are the origin of Response objects.

3.3   HTTP Header

Requirements:

Regardless of whether a remote procedure call is made using HTTP GET or POST, the HTTP request message MUST specify the following headers:

• Content-Type SHOULD be 'application/json-rpc' but MAY be 'application/json' or 'application/jsonrequest'
• The Content-Length MUST be specified and correct according to the guidelines and rules laid out in Section 4.4, Message Length, of the HTTP specification.
• The Accept MUST be specified and SHOULD read 'application/json-rpc' but MAY be 'application/json' or 'application/jsonrequest'.

3.4   POST

Post body contains the Object request specified in JSON-RPC 1.2 section 2.4.

Response to a Post contains the Object response specified in JSON-RPC 1.2 section 2.5.

Responses with a null error will result in an HTTP 200 Status Code, while non-null error codes will be mapped to HTTP Status code as specified in the Errors section.

--> POST /ENDPOINT HTTP/1.1
 Host: ...
 Content-Type: application/json-rpc
 Content-Length: ...

 {"method": "sum", "params": {"a":3, "b":4}, "id":0}

<-- HTTP/1.1 200 OK
 ...
 Content-Type: application/json-rpc

 {"result": 7, "error": null, "id": 0}


--> POST /ENDPOINT HTTP/1.1
 Host: ...
 Content-Type: application/json-rpc
 Content-Length: ...

 {"method": "test", "params": [], "id": 0}

3.5   GET

• MUST be either Array or Object parameters [1]
• Keep in mind that some old clients and proxies have issues wth URI lengths over 255 bytes [2]
• HTTP POST is the preferred method for sending JSON-RPC
• Parameters must be encoded

http://<end point>?method=<method name>&params=<encoded params>&id=1

http://<end point>?method=sum&params={"a":3,"b":4}&id=2
http://<end point>?method=sum&params=[3,4]&id=1

http://<end point>?method=sum&params=eyJhIjozLCJiIjo0fQ%3D%3D&id=2
http://<end point>?method=sum&params=WzMsNF0%3D&id=1

3.6   Response Codes