JavaScript / TypeScript SDK

The logstack-js package for Node.js, browsers, Deno, Bun, and edge runtimes.


npm	`logstack-js`
Import	`import { createLogStack } from "logstack-js"`
Default API	`https://api.logstack.tech`
Ingest path	`POST {endpoint}/v1/logs`

Installation

npm install logstack-js
# yarn add logstack-js · pnpm add logstack-js · bun add logstack-js

Quick start

import { createLogStack } from "logstack-js";
 
const logstack = createLogStack({
  apiKey: process.env.LOGSTACK_API_KEY!,
  // captureConsole defaults to true — existing console.* calls are shipped
});
 
logstack.info("User signed up", { userId: "user_123" });
logstack.warn("Rate limit approaching", { current: 90, limit: 100 });
logstack.error("Payment failed", { orderId: "order_456" });
logstack.critical("Database connection lost", { host: "db.example.com" });
 
await logstack.close();

Features

Automatic batching — buffer + flush interval
Retry with backoff — failed requests retried
captureConsole (default on) — ships console.* with source: "console"
Offline queue — browser localStorage cap (maxOfflineQueueSize)
TypeScript — full type definitions
Graceful shutdown — flush() / close()

Log levels

Level	Method	Use case
`debug`	`logstack.debug()`	Verbose diagnostics
`info`	`logstack.info()`	Normal operations
`warn`	`logstack.warn()`	Potential issues
`error`	`logstack.error()`	Failures
`critical`	`logstack.critical()`	Immediate attention
`fatal`	`logstack.fatal()`	Process-ending errors

API reference

`createLogStack(options)`

import { createLogStack } from "logstack-js";
 
const logstack = createLogStack({
  apiKey: "ls_live_xxx",
  endpoint: "https://api.logstack.tech",
  batchSize: 100,
  flushInterval: 5000,
  maxRetries: 3,
  environment: "production",
  captureConsole: true,
  onError: (error, logs) => {
    console.error("Failed to send logs:", error);
  },
});

Logging methods

logstack.info("User logged in", { userId: "user_123" });
logstack.warn("API rate limit approaching", { usage: 90 });
logstack.error("Database connection failed", { host: "db.example.com" });
logstack.critical("Payment processing unavailable", { service: "stripe" });
 
logstack.log({
  level: "error",
  message: "Operation failed",
  source: "worker-service",
  metadata: { jobId: "job_123" },
});

Flush and close

await logstack.flush();
await logstack.close();

Always call close() on graceful shutdown so buffered logs are not lost.

Explore more

Configuration

Batching, retries, captureConsole, environments

Logging best practices

Levels, metadata, sources, privacy

Framework integrations

Express, Next.js, Fastify, NestJS

Go SDK

Official Go client

Python SDK

Official Python client