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This is Yaws, a webserver for dynamic content written in Erlang.

Build Status

Yaws Mailing List

The erlyaws-list is used to discuss Yaws. You might find the erlyaws-list archives helpful.

Prepare build

Get and install an Erlang system (

To compile Yaws, Erlang/OTP 22.0 or higher is required.

If you've cloned the source from github and you want to build using autotools, note there is no ./configure script in the source, so create one:

$> autoreconf -fi

Install build dependencies. Required packages to compile Yaws are (based on debian packages):

  • build-essential
  • autoconf/automake/libtool
  • erlang - Required apps:
  • erlang-{kernel/stdlib/sasl/erts}
  • erlang-compiler
  • erlang-crypto
  • erlang-xmerl
  • libpam0g-dev

To build the documentation (optional), you also need to install:

  • texlive-latex-base
  • texlive-latex-recommended
  • texlive-fonts-recommended
  • texlive-font-utils
  • texlive-extra-utils
  • ghostscript

On Ubuntu/debian this is pretty much equal to:

$> apt-get build-dep yaws

On MacOS and OS X, be sure the necessary Xcode command-line tools and development environment are set up correctly by running the following command:

xcode-select --install

Finally, to run the testsuites, yaws need to install:

  • git
  • wget
  • curl
  • erlang-eunit
  • erlang-inets
  • erlang-mnesia
  • erlang-ssl
  • cadaver


You can build via autotools:

$> ./configure --prefix=/usr/local

or via rebar3 on the rebar3-support branch:

$> git switch rebar3-support
$> rebar3 compile

If using rebar3, you'll get a "local installation" that you can run via rebar3 shell.

If using autotools, the build will be configured by default for installation under /usr/local. For more information about installation directories and other supported options, see the configure help. Useful options are:

--with-defaultcharset=CHARSET specify default charset, i.e UTF-8
--with-extrainclude=DIR       dir to include if e.g. pam is installed in some odd place
--with-erlang=PREFIX          prefix where Erlang is installed (optional)

Note to packagers (rpm, deb ...) All install targets support the DESTDIR variable. Thus, if we do

$> ./configure --prefix=/usr; make

we can subsequently do:

$> make install DESTDIR=/foo/bar

All Yaws files will be installed under DESTDIR, but all code will assume Yaws should be installed under /usr.

Main make targets:

  • all : compile Yaws
  • debug : compile Yaws with debug flags
  • clean : remove files produced by all or debug target
  • install : do a proper install of Yaws
  • doc or docs : build the documentation
  • check or test : launch tests
  • cleantest : remove files produced by check target
  • dialyzer : run dialyzer on Yaws
  • mkinstaller : build an installer for windows
  • cleaninstaller: remove files produced by mkinstaller target
  • apps : compile Yaws applications (chat,mail,wiki,yapp)
  • cleanapps : remove files produced by apps target
  • installapps : install Yaws applications
  • fullinstall : install + installapps
  • fullclean : clean + cleantest + cleanapps + cleaninstaller

Reproducible builds

It is possible to build deterministically, thus enabling reproducible builds of Yaws.

A deterministic build is enabled either by running configure with options --enable-deterministic-build and --with-source-date-epoch:

$> ./configure --enable-deterministic-build \

or by setting the environment variables YAWS_DETERMINISTIC_BUILD and SOURCE_DATE_EPOCH before running autoreconf and configure, respectively:

$> export YAWS_DETERMINISTIC_BUILD=true # set to any value will enable
%> autoreconf -fi
$> export SOURCE_DATE_EPOCH=$known_unix_timestamp
$> ./configure

After either of the two configurations above are done, build as usual:

$> make all doc

The above configurations for enabling deterministic builds add the erlc flag +deterministic, drop the +debug_info flag, generate a deterministic yaws_generated.beam, and set e.g. creation date in and yaws.pdf from the value of SOURCE_DATE_EPOCH, which is expected to be an integer reflecting a number of seconds since the Unix epoch. (One way to get an epoch integer value is via the command date '+%s' on Linux or macOS, for example. If you're using the bash shell version 4.2 or newer, printf '%(%s)T\n' -1 gives an epoch integer value, and starting at version 5, the bash shell provides the $EPOCHSECONDS variable.)

Note that various paths in configuration files, templates, examples etc. are generated from the configured installation prefix config files; thus they will vary if the installation prefix is different across builds. This can be mitigated by using DESTDIR when installing (see the Build section above for more details).

Test your build

With autotools, to test the build, you should install it somewhere:

$> ./configure --prefix=$PWD/_inst && make install
$> $PWD/_inst/bin/yaws -i

If you used rebar3 to build Yaws, you can alternatively start Yaws with

$> rebar3 shell

Either approach will start a webserver at Terminate through ^C, or ^G followed by q, or

> init:stop()

NOTE: If you've used rebar3 to build the system, none of the following directions apply.

Install and run

NOTE: following commands may require root privileges, depending of the installation prefix.

Just run:

$> make install

Then, to run Yaws, you should use its script:

$> ${bindir}/yaws -i

This starts an interactive system.

With the default yaws.conf file, this will create a webserver at http://${host} and one at https://${host}.

You can adapt Yaws configuration by editing '${sysconfig}/yaws/yaws.conf'.

Daemonize Yaws

Start it using '--daemon' and '--heart' options:

$> ${bindir}/yaws --daemon --heart

This will start a daemon (--daemon) which will be autorestarted when/if it crashes or hangs (--heart). Also, for most unices, we create proper start scripts in ${sysconfdir}/init.d


$> autoreconf -fi
$> ./configure --sysconfdir=/etc
$> make && make install
$> /etc/init.d/yaws start

Security Policy

To report security vulnerabilities or other security-related issues, please refer to the Yaws security policy.