Upload FIX logs. Instantly diagnose issues.
Get actionable insights from FIX 4.2/4.4 sessions: missing tags, sequence gaps, heartbeat problems, and more.
How it works
1. Upload
Drop a FIX session log. We detect delimiters and parse tag=value pairs safely.
2. Analyze
We check mandatory tags, sequence continuity, heartbeats, rejects, malformed fields, and more.
3. Summarize
Get a clear summary, timeline, and top issues to speed up triage.
Free vs Full Diagnosis
Free
- Basic parsing and common errors
- Timeline with key events
Full Diagnosis
- Expanded rule set and recommendations
- Deeper FIX field validations
- Shareable report and export options
- Downloadable Summary (Coming Soon)
FIX Protocol Guides
FIX Reject 371
Learn about FIX Reject tag 371, common causes, and how to fix them.
FIX Sequence Gaps
Understand sequence number gaps and recovery methods.
NewOrderSingle Errors
Common NewOrderSingle (35=D) errors and how to diagnose them.
Online FIX Parser
Free instant FIX message analyzer and log parser.
OrderCancelReject Guide
OrderCancelReject (35=9) causes and how to fix them.
FIX Protocol Basics
Quick guide for trade support and developers.
FIX Tag Glossary
Definitions for all common FIX fields and tags.
FIX Onboarding Checklist
What every engineer should verify during FIX setup.
Common FIX Reject Codes
Explained: RefTagID, RefMsgType, session vs business rejects.
FIX Protocol Overview
How FIX works end-to-end: session and application layers.
FIX Troubleshooting Guide
Step-by-step procedure for diagnosing FIX issues.
FIX Error Code Library
Common FIX Problems Diagnosed Automatically
Tag 371 Missing ClOrdID
ClOrdID (tag 11) is required but missing from order messages.
Reject 102 – Too Late to Cancel
Order cancellation rejected because order is already filled or canceled.
Invalid Tag Value
Tag value doesn't match expected format or enum values.
FIX Gap Fill Issue
Sequence number gaps detected in FIX session.
Session Level Rejects
Required tag missing from message (SessionRejectReason=6).
View All Error Codes
Browse complete index of FIX error codes and troubleshooting guides.