KLogic

Debugging Kafka Messages: Inspection & Analysis

Find specific messages, decode serialized payloads, and diagnose data quality issues using KLogic's powerful message inspection and analysis tools.

KLogic Message Inspector

A real-time window into your Kafka topic data with powerful filtering and decoding

Live Message Feed

Stream messages from any topic partition in real time, or browse historical messages by specifying an offset range or time window.

Tail latest messages live
Jump to specific offset
Browse by timestamp range

Advanced Filtering

Filter messages by key, value content, headers, partition, or custom JMESPath expressions to find exactly what you need.

Key/value substring search
Header-based filtering
Partition-level targeting

Schema Decoding

Automatically decode Avro, Protobuf, JSON Schema, and raw JSON messages for human-readable inspection.

Auto-detect serialization format
Schema Registry integration
Pretty-print JSON output

Avro & Protobuf Decoding

Inspect serialized binary messages as human-readable structured data

Avro Decoding

KLogic integrates directly with Confluent Schema Registry to decode Avro messages. The schema ID embedded in the message wire format is used to fetch the correct schema.

Automatic Schema Lookup

Schema IDs in the Confluent wire format are resolved automatically from your Schema Registry.

Schema Evolution Support

Messages encoded with older schema versions are decoded correctly, showing which version was used.

Key & Value Separate

Both message key and value can have independent Avro schemas decoded simultaneously.

Protobuf Decoding

Upload your .proto descriptor files or connect to a Schema Registry with Protobuf support to decode binary messages.

Proto Descriptor Upload

Upload compiled .desc files to KLogic for message decoding without Schema Registry.

Nested Message Types

Complex nested Protobuf message hierarchies are expanded and displayed in a tree view.

oneof & Enum Support

Protobuf oneof fields and enum values are rendered with their symbolic names, not raw integers.

Decoded Message Example

Raw Binary (Base64)

AAAAAANPCg1vcmRlci0xMjM0NTYSEDEyMDAgV2lkZ2V0IFByb5HtAw==

Decoded Avro (Schema v3)

"order_id": "order-123456"
"product_name": "1200 Widget Pro"
"quantity": 3
"status": "CONFIRMED"
"created_at": "2024-03-28T14:32:00Z"

Finding Specific Messages

Techniques for locating messages across high-volume topics

Key-Based Lookup

If you know the message key, KLogic can calculate the partition using the standard Kafka partitioner and retrieve messages directly from that partition.

Example key lookup
Key: order-123456
Partition: 7 (computed)
Results: 3 messages found

Time-Based Search

Specify a time range to search messages produced during a specific window. KLogic uses Kafka's offsetsForTimes API for efficient seeking.

Time window search
From: 2024-03-28 14:00:00 UTC
To: 2024-03-28 14:30:00 UTC
Partitions: all (0-11)

Offset-Based Navigation

Jump directly to a known offset within a specific partition. Useful for replaying or investigating messages from error logs that include offsets.

Jump to exact offset
Browse relative to latest or earliest
Per-partition offset control

Header-Based Filtering

Many applications embed trace IDs, correlation IDs, or event types in message headers. Filter by any header key-value pair to trace a request through your system.

Filter by X-Trace-ID
Match event type headers
Combined key+header filters

Practical Debugging Workflow

A systematic approach to diagnosing message-level issues

1

Identify the Affected Topic & Time Window

Start with the topic where the issue was observed and narrow the time range to when errors were reported. Check consumer group lag spikes as a clue.

2

Configure the Correct Deserializer

Select Avro, Protobuf, JSON, or String deserializer in KLogic's message inspector. If using Schema Registry, ensure it is connected and accessible.

3

Apply Filters to Narrow Results

Use key search, value content filtering, or header matching to isolate the specific messages causing problems. Start broad, then narrow incrementally.

4

Inspect Message Structure

Examine decoded message fields for null values, unexpected types, missing required fields, or data outside expected ranges.

5

Correlate Across Topics

Use trace IDs from message headers to follow a request through multiple topics in your event-driven pipeline using KLogic's Flow Map view.

Debug Kafka Messages with Confidence

KLogic's message inspector gives you the visibility you need to diagnose data quality issues, trace events, and understand your Kafka data flows.

Free 14-day trial • Avro & Protobuf support • Schema Registry integration