streaming logs to the browser
JavaScript HTML CSS
Latest commit ece7dc9 Oct 6, 2016 @mthenw committed on GitHub update README

frontail – streaming logs to the browser

frontail is a Node.js application for streaming logs to the browser. It's a tail -F with UI.

Build Status Version

Quick start


  • log rotation
  • auto-scrolling
  • marking logs
  • number of unread logs in favicon
  • themes (default, dark)
  • highlighting
  • search (Tab to focus, Esc to clear)
  • tailing multiple files and stdin
  • basic authentication


npm i frontail -g

or use Docker image

docker run -d -P -v /var/log:/log mthenw/frontail /log/syslog


frontail [options] [file ...]


  -h, --help                    output usage information
  -V, --version                 output the version number
  -h, --host <host>             listening host, default
  -p, --port <port>             listening port, default 9001
  -n, --number <number>         starting lines number, default 10
  -l, --lines <lines>           number on lines stored in browser, default 2000
  -t, --theme <theme>           name of the theme (default, dark)
  -d, --daemonize               run as daemon
  -U, --user <username>         Basic Authentication username, option works only along with -P option
  -P, --password <password>     Basic Authentication password, option works only along with -U option
  -k, --key <key.pem>           Private Key for HTTPS, option works only along with -c option
  -c, --certificate <cert.pem>  Certificate for HTTPS, option works only along with -k option
  --pid-path <path>             if run as daemon file that will store the process id, default /var/run/
  --log-path <path>             if run as daemon file that will be used as a log, default /dev/null
  --ui-hide-topbar              hide topbar (log file name and search box)
  --ui-no-indent                don't indent log lines
  --ui-highlight                highlight words or lines if defined string found in logs, default preset
  --ui-highlight-preset <path>  custom preset for highlighting (see ./preset/default.json)

Web interface runs on[port].

Tailing multiple files

[file ...] accepts multiple paths, *, ? and other shell special characters(Wildcards, Quotes, Back Quotes and Apostrophes in shell commands).


Use - for streaming stdin:

./server | frontail -


--ui-highlight option turns on highlighting in UI. By default preset from ./preset/defatult.json is used:

    "words": {
        "err": "color: red;"
    "lines": {
        "err": "font-weight: bold;"

which means that every "err" string will be in red and every line with "err" will be bolded. Custom preset can be provided by

New presets are very welcome. If you don't like default or you would like to share your, please create PR with json file.