A high-performance Serilog formatter that outputs compact JSON optimized for AWS CloudWatch metric filters and structured log analysis.
Overview
The standard Serilog CompactJsonFormatter uses @ prefixed properties for metadata (like @l for level, @t for timestamp, etc.). However, these @ prefixed properties are not compatible with AWS CloudWatch metric filters, which cannot parse escaped metadata keys.
This formatter solves that problem by replacing the @ prefix with _ (underscore) while maintaining all the performance benefits of the original compact formatter.
Key Features
CloudWatch Compatible: Uses _ prefix instead of @ for metadata fields
High Performance: Based on the official Serilog compact formatter
Single-line JSON: Optimized for log ingestion and analysis
Full Serilog Integration: Drop-in replacement for CompactJsonFormatter
Trace Support: Includes trace ID and span ID support
using LayeredCraft.Logging.CompactJsonFormatter;
using Serilog;
Log.Logger = new LoggerConfiguration()
.WriteTo.Console(new CompactJsonFormatter())
.CreateLogger();
Log.Information("Hello, {Name}!", "World");
With Custom Value Formatter
using LayeredCraft.Logging.CompactJsonFormatter;
using Serilog;
using Serilog.Formatting.Json;
var customValueFormatter = new JsonValueFormatter(typeTagName: "$type");
Log.Logger = new LoggerConfiguration()
.WriteTo.Console(new CompactJsonFormatter(customValueFormatter))
.CreateLogger();
AWS CloudWatch Integration
using LayeredCraft.Logging.CompactJsonFormatter;
using Serilog;
using Serilog.Sinks.AwsCloudWatch;
Log.Logger = new LoggerConfiguration()
.WriteTo.AmazonCloudWatch(
logGroup: "/aws/lambda/my-function",
region: RegionEndpoint.USEast1,
formatter: new CompactJsonFormatter())
.CreateLogger();
