JSONL Viewer for Claude Code

A web tool for viewing Claude Code session history in JSONL format with clean cards for messages, tool calls, results, and timeline navigation.

What Claude Code Session JSONL Looks Like

JSONL (JSON Lines) is a format where each line is a standalone JSON event object.

In Claude Code session history, you will usually see:

• type: record type (system, user, assistant, result).
• timestamp: event time.
• message.content: an array of blocks, for example:
  • text for plain message content;
  • tool_use for a tool invocation request;
  • tool_result for the corresponding tool output.
• linkage tool_use.id ↔ tool_result.tool_use_id to match request and response.

Example:

{"type":"assistant","timestamp":"2026-04-24T12:00:00Z","message":{"content":[{"type":"tool_use","id":"tool-1","name":"Bash","input":{"command":"echo 42"}}]}}
{"type":"user","timestamp":"2026-04-24T12:00:01Z","message":{"content":[{"type":"tool_result","tool_use_id":"tool-1","content":"42"}]}}

What This Site Lets You Do

• Upload one or multiple .jsonl files via drag-and-drop or file picker.
• Parse logs and render structured message cards.
• Highlight entry types (system, user, agent, tool, result) and errors.
• Show paired tool request / tool result panels with quick copy actions for JSON/text.
• Navigate long sessions quickly using the side navigation list.
• Switch between light and dark themes.

Open Online

Use the live viewer: jsonl.qent.io.