diff --git a/loglens/formatters/json_formatter.py b/loglens/formatters/json_formatter.py
index 18f286a..8dda494 100644
--- a/loglens/formatters/json_formatter.py
+++ b/loglens/formatters/json_formatter.py
@@ -1,14 +1,57 @@
+"""JSON output formatter."""
+
 import json
 from typing import Any
 
 from loglens.analyzers.analyzer import AnalysisResult
+from loglens.formatters.base import OutputFormatter
+from loglens.parsers.base import ParsedLogEntry
 
 
-class JSONFormatter:
-    """Format analysis results as JSON."""
+class JSONFormatter(OutputFormatter):
+    """Formats output as JSON."""
 
-    def format(self, result: Any) -> str:
-        """Format result as JSON."""
-        if hasattr(result, "to_dict"):
-            return json.dumps(result.to_dict(), indent=2)
-        return json.dumps(result, indent=2)
+    def format(self, data: Any) -> str:
+        """Format data as JSON."""
+        if isinstance(data, AnalysisResult):
+            return self._format_analysis_result(data)
+        elif isinstance(data, list):
+            return self._format_entries(data)
+        else:
+            return json.dumps(data, default=str, indent=2)
+
+    def _format_analysis_result(self, result: AnalysisResult) -> str:
+        """Format analysis result as JSON."""
+        output = {
+            "summary": {
+                "total_lines": result.total_lines,
+                "parsed_entries": result.parsed_count,
+                "format_detected": result.format_detected.value,
+                "analysis_time": result.analysis_time.isoformat(),
+            },
+            "severity_breakdown": result.severity_breakdown,
+            "pattern_matches": result.pattern_matches,
+            "top_errors": result.top_errors,
+            "host_breakdown": result.host_breakdown,
+            "suggestions": result.suggestions,
+        }
+
+        if result.time_range:
+            output["time_range"] = {
+                "start": result.time_range[0].isoformat(),
+                "end": result.time_range[1].isoformat(),
+            }
+
+        return json.dumps(output, default=str, indent=2)
+
+    def _format_entries(self, entries: list[ParsedLogEntry]) -> str:
+        """Format log entries as JSON array."""
+        output = [entry.to_dict() for entry in entries]
+        return json.dumps(output, default=str, indent=2)
+
+    def format_entries_compact(self, entries: list[ParsedLogEntry]) -> str:
+        """Format entries as compact JSON (one per line)."""
+        lines = []
+        for entry in entries:
+            lines.append(json.dumps(entry.to_dict(), default=str))
+        return "\n".join(lines)