Configuration¶

createCipherLogger(config?) accepts a single optional CipherLoggerConfig object. Nothing is required — every option has a safe default.

import { createCipherLogger } from "cipher-logger";

const cipher = createCipherLogger({
  // Optional fields — default: false (disabled)
  fields: {
    ip: true,
    userAgent: true,
    referer: false,
    protocol: true,
    host: true,
    query: true,
    requestId: true,
    metadata: false,
  },

  // Log level: debug | info | warn | error
  level: "info",

  // Optional prefix in console output
  prefix: "api",
});

Top-level options¶

Option	Type	Default	Description
`fields`	`Partial<Record<OptionalRequestField, boolean>>`	all `false`	Optional log fields to include
`level`	`"debug" \\| "info" \\| "warn" \\| "error"`	`"debug"`	Minimum log level that gets emitted
`prefix`	`string`	—	Prefix shown in every console line

Log level filtering

Setting level: "info" silences logger.debug(...) calls but still emits info, warn, and error. Use "debug" in development and "info" or "warn" in production to cut noise.

`fields` — optional field flags¶

Every key defaults to false. Turn on only what you actually consume downstream — each enabled field adds a small amount of per-request overhead (reading a header, parsing a query string, etc.).

Field	Type	What it captures
`ip`	`boolean`	Client IP address
`userAgent`	`boolean`	`User-Agent` header
`referer`	`boolean`	`Referer` header
`protocol`	`boolean`	Protocol (`http` / `https`)
`host`	`boolean`	`Host` header
`query`	`boolean`	Query string parameters
`requestId`	`boolean`	Value of `x-request-id`
`metadata`	`boolean`	Custom metadata you pass in

See Log Schema for the exact runtime type of each field once enabled.

Choosing a `prefix` per environment¶

A common pattern is one logger per subsystem, so log lines are easy to grep:

const apiLogger = createCipherLogger({ prefix: "api", level: "info" });
const workerLogger = createCipherLogger({ prefix: "worker", level: "warn" });

Passing `metadata`¶

metadata is the escape hatch for anything CipherLogger doesn't capture automatically — user IDs, tenant IDs, feature flags, trace IDs from an APM tool, etc. Enable it in fields, then supply it manually via logRequest:

cipher.logRequest({
  method: "POST",
  path: "/orders",
  status: 201,
  duration: 42,
  metadata: { userId: "usr_123", tenant: "acme" },
});

Next steps¶

Express — mount as middleware, get accurate timing for free
Next.js — middleware.ts setup and its current timing limitation
API Reference — full type signatures