Logger

Better-Notify logs internally through a structural LoggerLike interface. Every createClient instance accepts an optional logger — if omitted, it defaults to consoleLogger({ level: 'warn' }), which stays silent on success and surfaces errors.

import { createClient, consoleLogger } from '@betternotify/core';

const mail = createClient({
  catalog,
  transportsByChannel: { email: transport },
  logger: consoleLogger({ level: 'debug' }),
});

The LoggerLike interface

Any object that implements these methods works as a logger — no base class or dependency required:

consoleLogger

The built-in logger. Outputs colored, human-readable lines with timestamps, level tags, and structured payload formatting. Errors under the err key get special treatment — stack traces are indented and cause chains are rendered recursively.

import { consoleLogger } from '@betternotify/core';

const logger = consoleLogger({ level: 'info' });

Pino integration

If you use pino, wrap it with fromPino — it adapts pino's (obj, msg) signature to Better-Notify's (msg, obj) convention:

import pino from 'pino';
import { fromPino } from '@betternotify/core/logger';

const logger = fromPino(pino({ level: 'info' }));

const mail = createClient({
  catalog,
  transportsByChannel: { email: transport },
  logger,
});

fromPino also forwards child() calls, so per-send bindings (route, messageId, component) flow through to pino child loggers.

Bring your own logger

Any object matching LoggerLike works — Winston, Bunyan, or a custom wrapper:

import type { LoggerLike } from '@betternotify/core';

const customLogger: LoggerLike = {
  debug: (msg, payload) => myLogger.log('debug', msg, payload),
  info: (msg, payload) => myLogger.log('info', msg, payload),
  warn: (msg, payload) => myLogger.log('warn', msg, payload),
  error: (msg, payload) => myLogger.log('error', msg, payload),
  child: (bindings) => customLogger,
};

Error key convention

Errors are always passed under the err key in payloads — this matches pino's stdSerializers.err convention. The console logger serializes err values with type, message, code, stack, and nested causes. If you're building a custom logger, handle the err key to get structured error output.