A modern, lightweight, and type-safe structured logger for real-time infrastructure.

Voltlog-io is a structured logger designed for high-throughput systems like IoT platforms, WebSocket servers, and microservices. It is the default logging engine for ocpp-ws-io but works as a standalone logger in any TypeScript/JavaScript project.

If you are using ocpp-ws-io, you can import it directly from the package:

import { createLogger } from "ocpp-ws-io/logger";

No need to install voltlog-io separately.

It resolves common pain points in event-driven architectures: context tracking, sensitive data redaction, high-volume sampling, and developer experience.

✨ Key Features

🚀 Zero-Dependency Core: Lightweight and fast. Only uses cuid2 for ID generation.
🔒 Secure by Design: Built-in redaction middleware for passwords, tokens, and headers.
📊 High-Throughput Ready: Intelligent sampling to log 1% of debug logs while keeping 100% of errors.
⚡ Developer Experience: Beautiful, icon-rich pretty printing for local development.
🔌 Universal Compatibility: Works in Node.js, Bun, Deno, and Browsers.
🤖 AI Powered: Built-in middleware to enrich error logs with AI analysis.
🧩 Pluggable Architecture: 10+ Middlewares and 12+ Transports included out of the box.

📦 Architecture

Voltlog uses a pipeline architecture:

Logger: The entry point (logger.info(...)). Generates the log entry.
Context: Attaches bound context (e.g., sessionId) and dynamic context (e.g., performance.now()).
Middleware: A chain of functions that process, filter, or enrich the log entry.
Transports: The final destinations (Console, File, Redis, Datadog...) where the log is sent.

🛠 Included Modules

Voltlog is strictly typed and works out of the box.

Transports (Destinations)

Transport	Description	Environment
Console	Standard JSON output to stdout/stderr.	Universal
Pretty	Colorful, human-readable output for development.	Universal
File	Writes logs to rotating files on disk.	Server
JSON Stream	Writes NDJSON to any WritableStream.	Server
Browser Stream	Writes NDJSON to WHATWG Streams.	Browser
Batch	Buffers logs for performance.	Universal
Redis	Publishes logs to Redis Streams.	Server
Datadog	Sends logs to Datadog Intake API.	Universal
Loki	Pushes logs to Grafana Loki.	Universal
Slack	Sends notifications to Slack Webhooks.	Universal
Discord	Sends notifications to Discord Webhooks.	Universal
Sentry	Captures errors and breadcrumbs in Sentry.	Universal
Webhook	POSTs logs to any HTTP endpoint.	Universal

Middlewares (Processors)

Middleware	Description
Redaction	Masks sensitive fields (password, token).
Sampling	Probabilistic logging to reduce volume.
Alert	Triggers callbacks/alerts based on conditions.
AI Enrichment	Uses LLMs to explain errors in real-time.
OCPP	Specialized formatting for OCPP messages.
Correlation ID	Tracks requests across services.
Deduplication	Groups identical logs in a time window.
Heap Usage	Adds memory stats (RSS/Heap) to logs.
IP Extraction	Extracts client IP from headers.
User Agent	Parses browser/OS info from UA string.
Level Override	Force log level dynamically via headers.

🚀 Getting Started

Ready to log? Check out the Quick Start guide.

Introduction