Local log analysis guide
JSON log viewer for files that stay private
Open JSON, JSONL and newline-delimited logs locally. Format structured entries, search any field and export only the lines you need.
Structured logs make incidents easier to investigate only when the structure remains readable. Log Voyager detects JSON objects inside log lines and formats them without sending the source file to a server.
Use it for application logs from Node.js, Python, Go and Java, or for JSON output copied from container and cloud tooling. Search by trace ID, request ID, service, level or any literal value stored in the event.
Files and formats
.json · .jsonl · .ndjson · .log · .txt · .gz
Common investigation tasks
Follow one request
Search a trace_id, correlation_id or request_id across every matching event.
Isolate error objects
Filter ERROR entries, then inspect nested message, stack and context fields.
Read compact JSON
Pretty-print single-line objects while keeping the original log order intact.
Export evidence
Select matching entries and export a smaller TXT, JSON or CSV working set.
A practical workflow
- Open the file - Choose a JSON, JSONL, NDJSON or compressed text log from your device.
- Find the field - Search a key, value or regular expression. Enable case matching only when the format requires it.
- Read the context - Move between matches, bookmark relevant lines and compare nearby events.
- Export the subset - Save selected evidence without copying the entire production log.
Frequently asked questions
Does the JSON file get uploaded?
No. File reading, searching and formatting run in your browser. The selected file is not sent to Log Voyager servers.
Does it support JSONL and NDJSON?
Yes. Newline-delimited JSON works naturally because Log Voyager reads and displays log entries line by line.
Can I search nested JSON fields?
You can search the rendered line for nested keys and values. Regex and case-sensitive matching are available for more precise patterns.