SIP Header Checker
Run rule-based checks on a SIP start line, common headers, Content-Length, and optional SDP to identify frequent formatting and consistency problems.
1. Input SIP Message
Paste your SIP message (request or response) below.
2. Validation Results
Valid Headers
9
Warnings
2
Errors
0
Total Headers
11
3. Header Details
Detailed analysis for the selected header
Analysis
Without transport=udp/tcp/tls downstream proxies may pick the wrong transport.
Recommended format: <sip:user@host:port;transport=udp>
Best Practice
Specify the transport parameter (udp/tcp/tls) in Contact header for better compatibility.
RFC Reference
RFC 3261 §20.10.2 - Contact
What is SIP Header Checker?
Run rule-based checks on a SIP start line, common headers, Content-Length, and optional SDP to identify frequent formatting and consistency problems. One raw SIP request or response, optionally containing SDP. Warnings and errors for request/status line, Via branch, Max-Forwards, Contact, Content-Length mismatch, and selected SDP issues.
Open the tool
What the tool does
- Input: One raw SIP request or response, optionally containing SDP.
- Controls and processing: Paste the message, run checks, inspect severity and rule explanations, then copy corrected parts into the builder/parser workflow.
- Output: Warnings and errors for request/status line, Via branch, Max-Forwards, Contact, Content-Length mismatch, and selected SDP issues.
How to use it
- Provide the input. One raw SIP request or response, optionally containing SDP.
- Review the settings. Paste the message, run checks, inspect severity and rule explanations, then copy corrected parts into the builder/parser workflow.
- Generate, inspect, and export. Warnings and errors for request/status line, Via branch, Max-Forwards, Contact, Content-Length mismatch, and selected SDP issues.
Key features
- Input: One raw SIP request or response, optionally containing SDP.
- Controls and processing: Paste the message, run checks, inspect severity and rule explanations, then copy corrected parts into the builder/parser workflow.
- Output: Warnings and errors for request/status line, Via branch, Max-Forwards, Contact, Content-Length mismatch, and selected SDP issues.
Useful workflows
- Run rule-based checks on a SIP start line, common headers, Content-Length, and optional SDP to identify frequent formatting and consistency problems.
- Use it when you need this deliverable or diagnostic result: Warnings and errors for request/status line, Via branch, Max-Forwards, Contact, Content-Length mismatch, and selected SDP issues.
- Place it before the next verified workflow step: testing the corrected message against the authorized SIP stack and call scenario.
Limits and safety notes
- This is a rule-based checker, not proof of complete RFC 3261 compliance or interoperability. Validity depends on message role, method, transaction/dialog state, extensions, transport, and peer behavior.
Troubleshooting
- Paste only the raw value or message expected by the tool; preserve quotes, delimiters, escaping, and line endings, then test a minimal valid sample.
- If parsing succeeds but the meaning is wrong, compare the output with the target standard or runtime; successful parsing is not proof of operational validity.
- This is a rule-based checker, not proof of complete RFC 3261 compliance or interoperability. Validity depends on message role, method, transaction/dialog state, extensions, transport, and peer behavior.
Frequently asked questions
What is SIP Header Checker?
Run rule-based checks on a SIP start line, common headers, Content-Length, and optional SDP to identify frequent formatting and consistency problems.
How do I use SIP Header Checker?
Provide the expected input, review the page settings, then verify the result before copying or downloading it. Expected output: Warnings and errors for request/status line, Via branch, Max-Forwards, Contact, Content-Length mismatch, and selected SDP issues.
What input does it accept?
One raw SIP request or response, optionally containing SDP.
What output does it produce?
Warnings and errors for request/status line, Via branch, Max-Forwards, Contact, Content-Length mismatch, and selected SDP issues.
What are the limits?
This is a rule-based checker, not proof of complete RFC 3261 compliance or interoperability. Validity depends on message role, method, transaction/dialog state, extensions, transport, and peer behavior.
Related AppKiro tools
Start with a verified input
Test with a small, non-sensitive sample, verify the key settings and output, then apply the result to the real workflow.
Open the tool