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Every time you invoke reader scrape or reader crawl, Reader normally spins up a fresh browser pool, runs your command, and tears it down. That’s fine for one-off scripts but wasteful when you’re making many calls - you pay the 1-2 second pool startup cost every time. Daemon mode fixes this. Start a background daemon once, and all subsequent CLI commands auto-attach to it, reusing the warm pool.

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Start the daemon

reader start --pool-size 5
This starts a background process listening on port 4000 (default) with a 5-instance browser pool. The first CLI command will feel instant - no startup cost. Optional flags:
FlagPurpose
--pool-size <n>Browser pool size (default: 5)
--port <n>Listen port (default: 4000)
--show-chromeShow browser windows (debugging)
-v, --verboseEnable logging

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Check status

reader status
Reports whether the daemon is running, its pool size, and the number of in-flight requests.

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Use the daemon transparently

Once the daemon is running, just use reader scrape and reader crawl as normal: 
# First call - attaches to daemon automatically
reader scrape https://example.com

# Second call - also uses the daemon, instant startup
reader scrape https://another.com
The CLI auto-detects a running daemon on the default port. To use a custom port: 
reader start --port 5000
reader scrape -p 5000 https://example.com

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Bypass the daemon

For one-off runs where you don’t want to touch the daemon (e.g., you want to test without affecting the shared pool): 
reader scrape --standalone https://example.com
This runs in standalone mode regardless of whether a daemon is running.

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Stop the daemon

reader stop

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When to use daemon mode

  • Shell scripts that run Reader many times in sequence
  • Development where you’re iterating on CLI commands
  • Cron jobs that fire frequently (keep the daemon warm rather than cold-start on every run)

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When not to use it

  • Single one-off commands - the daemon startup cost exceeds the savings
  • CI/CD - each build should be stateless; just use --standalone or skip daemon entirely
  • Server applications - embed ReaderClient directly in your Node app instead; the CLI daemon is for terminal workflows

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Where to go next

CLI guide

Commands and flags for scrape and crawl.

Deployment

Running Reader as a production service.