JSON Schema & SDP Support¶

To streamline integration with modern NoSQL databases (DocumentDB, Azure Cosmos DB, MongoDB, Elasticsearch), sip2json represents SIP messages as structured JSON documents.

Schema Overview¶

The document uses single-character keys (s, h, b, meta) to minimize payload size during network transmission and indexing.

{
  "meta": {
    "version": "sip2json/3.2.0/1.0.2",
    "time": "2026-08-18T15:30:00.000Z",
    "ttx": 0
  },
  "s": {
    "type": "request",
    "method": "INVITE",
    "uri": "sip:user@example.com",
    "version": "SIP/2.0"
  },
  "h": {
    "Call-ID": "c30382-990-12@10.0.0.1",
    "CSeq": "1 INVITE",
    "From": "sip:caller@example.com;tag=991a",
    "To": "sip:user@example.com",
    "Via": [
      "SIP/2.0/TCP 10.0.0.1:5060;branch=z9hG4bK776"
    ],
    "Content-Length": 142
  },
  "b": {
    "sdp": [
      {
        "v": 0,
        "o": {"user": "-", "t1": "2890844526", "t2": "2890844526", "type": "IN", "subtype": "IP4", "host": "10.0.0.1"},
        "s": "-",
        "c": {"type": "IN", "subtype": "IP4", "dn": "10.0.0.1"},
        "t": [0, 0],
        "m": "audio 49170 RTP/AVP 0 8 96",
        "a": {
          "rtpmap": ["0 PCMU/8000", "8 PCMA/8000"]
        }
      }
    ]
  }
}

Document Fields¶

Field	Type	Description
`s`	`object`	Start line container (Request line or Status line)
`meta`	`object`	Diagnostics: library version, ISO timestamp, parse time (`ttx` in ms)
`h`	`object`	Header key-value pairs. Arrays represent multi-instance headers (e.g. `Via`)
`b`	`object`	Optional body container (e.g. SDP descriptors)

Header Type Conversions¶

Numeric fields like Content-Length and Expires are converted to JSON unsigned integers during stream parsing.
Standard headers are parsed as JSON strings. Boolean extensions, numeric values, and custom structures can be assigned programmatically using setHeader(), which the wire serializer formats correctly.
Headers occurring multiple times in a SIP message (e.g. Via, Record-Route, Supported) are represented as JSON string arrays.

SDP (Session Description Protocol) Support¶

sip2json includes built-in parsing and serialization for application/sdp payload bodies.

SDP lines (v=, o=, s=, c=, t=, m=, a=) are parsed into structured JSON objects inside b.sdp.

{
  "v": 0,
  "o": {
    "user": "Alice",
    "t1": "2890844526",
    "t2": "2890844526",
    "type": "IN",
    "subtype": "IP4",
    "host": "10.0.0.5"
  },
  "s": "SIP Call",
  "c": {
    "type": "IN",
    "subtype": "IP4",
    "dn": "10.0.0.5"
  },
  "t": [0, 0],
  "m": "audio 49170 RTP/AVP 0 101",
  "a": {
    "rtpmap": [
      "0 PCMU/8000",
      "101 telephone-event/8000"
    ],
    "fmtp": "101 0-16",
    "sendrecv": true
  }
}

SDP Attribute Mapping Rules¶

Flag attributes like a=sendrecv are stored as boolean true.
Repeated attribute keys like a=rtpmap:... are accumulated into array values.
Key-value attributes like a=fmtp:101 0-16 are separated into string mappings.