WebRTC SDP & ICE Candidate Inspector

What does the WebRTC SDP & ICE Candidate Inspector do?

The WebRTC SDP & ICE Candidate Inspector helps WebRTC developers, VoIP engineers, and video streaming architects parse, inspect, and lint Session Description Protocol (SDP) Offer/Answer exchanges and ICE candidate lines (a=candidate:). It visualizes media descriptions (m=audio, m=video), checks DTLS setup roles, audits payload types, and provides 1-click IP/credential sanitization for safe public log sharing.

Core Concepts

Understanding WebRTC Session Negotiation:

• SDP Offer / Answer: Textual session descriptions exchanged via signaling (SIP/WebSocket) detailing media capabilities, codecs, and transport parameters.
• DTLS Setup Roles (a=setup:): Negotiates active/passive TLS roles during handshake (actpass, active, passive).
• ICE Candidate Types:
  • host: Local network interface IP address.
  • srflx (Server Reflexive): Public IP assigned by STUN server.
  • relay: Relayed IP assigned by TURN server.

How to use the tool?

1. Input Session Data: Paste your SDP Offer and Answer strings, or input a single a=candidate: line.
2. Real-time Diagnostics: The linter audits DTLS setup roles, codec payload matches, and ICE credentials.
3. 1-Click Sanitizer: Click 🔒 1-Click Sanitize IPs & Keys to replace private IPv4/IPv6 addresses and ufrag/pwd tokens with safe placeholders before sharing logs.

Related Developer Utilities

If you work with network protocols and media streaming, explore these complementary tools:

• CIDR Subnet Calculator: Calculate IPv4 subnet boundaries, broadcast addresses, and netmasks.
• Port Lookup Utility: Search common TCP/UDP service ports and network protocols.

REST API Integration

Blueutils provides a free REST API endpoint (POST https://blueutils.com/api/network/webrtc-sdp-inspector) to programmatically lint SDP documents and deconstruct ICE candidate strings.

API Request Parameters

API Request Payload Examples

cURL

curl -X POST https://blueutils.com/api/network/webrtc-sdp-inspector \
  -H "Content-Type: application/json" \
  -d '{
    "candidateLine": "a=candidate:42349 1 UDP 2122260223 192.168.1.100 54321 typ host"
  }'

Python

import requests

url = "https://blueutils.com/api/network/webrtc-sdp-inspector"
payload = {
    "candidateLine": "a=candidate:42349 1 UDP 2122260223 192.168.1.100 54321 typ host"
}
headers = {"Content-Type": "application/json"}
response = requests.post(url, json=payload, headers=headers)
print(response.json())

Java

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class Main {
    public static void main(String[] args) throws Exception {
        String jsonPayload = """
            {
                "candidateLine": "a=candidate:42349 1 UDP 2122260223 192.168.1.100 54321 typ host"
            }
            """;

        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create("https://blueutils.com/api/network/webrtc-sdp-inspector"))
            .header("Content-Type", "application/json")
            .POST(HttpRequest.BodyPublishers.ofString(jsonPayload))
            .build();

        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
        System.out.println(response.body());
    }
}

API Response Parameters

API Response Payload Examples

Success Response (HTTP 200 OK)

{
  "isValid": true,
  "standaloneCandidate": {
    "foundation": "42349",
    "component": "RTP (1)",
    "protocol": "UDP",
    "priority": "2122260223",
    "ip": "192.168.1.100",
    "port": "54321",
    "type": "host"
  },
  "lintIssues": []
}

Validation Failure Response (HTTP 400 Bad Request)

{
  "isValid": false,
  "error": "Please enter a SDP Offer, Answer, or ICE candidate line to inspect."
}

Rate Limit Exceeded Response (HTTP 429 Too Many Requests)

{
  "error": "API rate limit exceeded. Please wait or contact support@blueutils.com."
}

Why use an API to inspect WebRTC SDPs?

Integrating the WebRTC SDP Inspector API into automated testing tools and WebRTC monitoring backend services offers key benefits:

• Automated Signaling Audits: Validate DTLS setup roles and codec payloads before establishing PeerConnections.
• ICE Candidate Analytics: Deconstruct candidate priorities and transport types during call quality debugging.

Native Usage

How to parse WebRTC SDPs programmatically across environments:

Node.js (JavaScript)

function parseIceCandidate(line) {
  const parts = line.replace('a=candidate:', '').trim().split(/\s+/);
  return {
    foundation: parts[0],
    component: parts[1] === '1' ? 'RTP' : 'RTCP',
    protocol: parts[2],
    priority: parts[3],
    ip: parts[4],
    port: parts[5],
    type: parts[7]
  };
}

console.log(parseIceCandidate('a=candidate:42349 1 UDP 2122260223 192.168.1.100 54321 typ host'));

Linux (Bash Shell)

#!/bin/bash
LINE="a=candidate:42349 1 UDP 2122260223 192.168.1.100 54321 typ host"
echo "$LINE" | awk '{print "IP:" $5 " Port:" $6 " Protocol:" $3 " Type:" $8}'

Python

def parse_ice_candidate(candidate_str):
    parts = candidate_str.replace("a=candidate:", "").strip().split()
    return {
        "ip": parts[4],
        "port": parts[5],
        "protocol": parts[2],
        "type": parts[7]
    }

print(parse_ice_candidate("a=candidate:42349 1 UDP 2122260223 192.168.1.100 54321 typ host"))

Java

public class SdpParser {
    public static void main(String[] args) {
        String line = "a=candidate:42349 1 UDP 2122260223 192.168.1.100 54321 typ host";
        String[] parts = line.replace("a=candidate:", "").trim().split("\\s+");
        System.out.println("Type: " + parts[7] + ", IP: " + parts[4] + ", Port: " + parts[5]);
    }
}