Configuration reference

Import defineConfig from flash-tunnel for editor completion. See configuration basics for discovery, paths, and precedence.

Domain

Field	Type	Default / behavior
domain.provider	string	'cloudflare'
domain.zone	string	Inferred when possible; otherwise supply a zone
domain.subdomain	string	'{project}-{rand}'

Supply a full hostname through --hostname or FLASH_TUNNEL_HOSTNAME. domain.hostname is not part of the config interface. Subdomain placeholders are documented in custom domains.

Server

Field	Type	Default / behavior
server.command	string	Auto-detected startup script
server.cwd	string	Config directory when a file is loaded; otherwise the project directory
server.port	number	Detected from script / framework / server mode
server.url	string	Existing server to attach to
server.dir	string	Static directory to serve
server.timeout	number	60000 milliseconds; positive integer

command, url, and dir describe different server modes; choose one. Relative paths resolve from the config directory. --attach requires a URL and cannot be combined with a command.

Tunnel

Field	Type	Default
tunnel.provider	string	'cloudflare'
tunnel.mode	'named' | 'quick'	'named'
tunnel.name	string	'flash-tunnel-{project}-{rand}'

Quick mode obtains a random trycloudflare.com URL and ignores a generated named-mode hostname. Built-in provider support can be inspected with flash-tunnel providers; setting a provider string alone does not install a new adapter.

Cloudflare provider

Field	Type	Default / behavior
providers.cloudflare.accountId	string	Discovered from the token when unambiguous
providers.cloudflare.zoneId	string	Resolved from the zone name
providers.cloudflare.cloudflaredPath	string	'cloudflared'
providers.cloudflare.originRequest.httpHostHeader	string	Optional origin Host-header override
providers.cloudflare.originRequest.noTLSVerify	boolean	Optional origin TLS-verification override

noTLSVerify: true disables verification of the origin certificate. Use it only when you deliberately need that behavior for a local HTTPS server.

There is no API-token field. Credentials come from CLOUDFLARE_API_TOKEN only.

Automatic shutdown

Field	Type	Default / behavior
autoStopAfter	string | number	No automatic time limit unless configured

Use '90s', '30m', '2h', or a number in milliseconds. At expiry, flash-tunnel stops the session and cleans up.

Example with an existing server

import { defineConfig } from 'flash-tunnel'

export default defineConfig({
  server: { url: 'http://127.0.0.1:3000' },
  tunnel: { mode: 'quick' },
  autoStopAfter: '30m'
})

Definitions are maintained in the source config types and config resolver.