index.html

---
title: Crystal
layout: home
custom_body_classes:
- main
---
<div class="banner center sponsorship no-select">
  <div class="flag">
    Fund Crystal and help it keep growing at
    <div class="flag-logos">
      <a href="https://opencollective.com/crystal-lang" target="_blank">
        <img src="/assets/oc.png" class="oc-logo">
      </a>
    </div>
  </div>
</div>

<div class="container">
  <div class="row center">
    <div class="col s12">
      {% assign latest_release = site.releases | reverse | first %}
      <h2 class="latest-release">Latest release <a href="{{ latest_release.url }}">{{ latest_release.version }}</a></h2>
      <p>{{ latest_release.date | date: "%d %B %Y" }} - <a href="/blog#release_notes" class="gray-link">More release notes</a></p>
    </div>
  </div>

  <hr class="fullwidth" />

  <div class="row">
    <div class="col s12">
      <h2>Syntax</h2>
      <p>Crystal’s syntax is heavily inspired by Ruby’s, so it feels natural to read and easy to write, and has the
        added benefit of a lower learning curve for experienced Ruby devs.</p>
      <div class='code_section'>
        {% include sample_server.md %}
      </div>
      <p class="read-more"><a href="https://crystal-lang.org/reference/getting_started/">Start learning Crystal with the Language
          Reference</a></p>
    </div>
  </div>

  <div class="row">
    <div class="col s12">
      <h2>Type system</h2>
      <p>Crystal is statically type checked, so any type errors will be caught early by the compiler rather than fail on
        runtime. Moreover, and to keep the language clean, Crystal has built-in type inference, so most type annotations
        are unneeded.</p>
      <div class="code_section">
        {% include sample_type_system.md %}
      </div>
      <p class="read-more"><a href="https://crystal-lang.org/reference/syntax_and_semantics/types_and_methods.html">Read more
          about Crystal's type system</a></p>
    </div>
  </div>

  <div class="row">
    <div class="col s12">
      <h2>Null reference checks</h2>
      <p>All types are non-nilable in Crystal, and nilable variables are represented as a union between the type and
        nil. As a consequence, the compiler will automatically check for null references in compile time, helping
        prevent the dreadful <a href="https://www.infoq.com/presentations/Null-References-The-Billion-Dollar-Mistake-Tony-Hoare" target="_blank">billion-dollar mistake</a>.</p>
      <div class="code_section">
        {% include sample_null.md %}
      </div>
      <p>Running the previous file:</p>
      <div class="code_section">
        <figure class="highlight console">
          {% include sample_null_refs.html %}
        </figure>
      </div>
    </div>
  </div>

  <div class="row">
    <div class="col s12">
      <h2>Macros</h2>
      <p>Crystal’s answer to metaprogramming is a powerful macro system, which ranges from basic templating and AST
        inspection, to types inspection and running arbitrary external programs.</p>
      <div class="code_section">
        {% include sample_macros.md %}
      </div>
      <p class="read-more"><a href="https://crystal-lang.org/reference/syntax_and_semantics/macros.html">Read more about
          macros</a></p>
    </div>
  </div>

  <div class="row">
    <div class="col s12">
      <h2>Concurrency Model</h2>
      <p>Crystal uses green threads, called fibers, to achieve concurrency. Fibers communicate with each other using
        channels, as in Go or Clojure, without having to turn to shared memory or locks. </p>
      <div class="code_section">
        {% include sample_concurrency.md %}
      </div>
      <p class="read-more"><a href="https://crystal-lang.org/reference/guides/concurrency.html">Read more about Crystal's
          concurrency model</a></p>
    </div>
  </div>

  <div class="row">
    <div class="col s12">
      <h2>C-bindings</h2>
      <p>Crystal has a dedicated syntax to easily call native libraries, eliminating the need to reimplement low-level
        tasks.</p>
      <div class="code_section">
        {% include sample_bindings.md %}
      </div>
      <p class="read-more"><a href="https://crystal-lang.org/reference/syntax_and_semantics/c_bindings/">Learn how to bind to
          C libraries</a></p>
    </div>
  </div>

  <div class="row">
    <div class="col s12">
      <h2>Dependencies</h2>
      <p>Crystal libraries are packed as Shards, and distributed via Git without needing a centralised repository. Built
        in commands allow dependencies to be easily specified through a YAML file and fetched from their respective
        repositories.</p>
      <div class="code_section">
        {% include sample_dependencies.md %}
      </div>
      <p class="read-more"><a href="https://github.com/crystal-lang/shards">Read more about Shards in the repo</a></p>
    </div>
  </div>

  <div class="row center">
    <div class="col s12">
      <div class="flag">
        <h3>Crystal top sponsors</h3>
        <a href="/sponsors">Meet all</a>
      </div>
    </div>
  </div>

  <div class="row">
    <div class="col s12">
      <div class='sponsors-list'>
        <a href='https://manas.tech/' target='_blank' class="sponsor">
          <img src="/assets/manas-orange.svg" />
          <span class="small">Manas Technology Solutions</span>
        </a>
        <a href='https://www.84codes.com/' target='_blank' class="sponsor">
          <img src="/assets/sponsors/84.png" />
          <span class="small">84 codes</span>
        </a>
        <a href='https://nikolamotor.com/' target='_blank' class="sponsor">
          <img src="/assets/sponsors/nikola_motor_company.png" />
          <span class="small">Nikola Motor Company</span>
        </a>
        <a href='https://place.technology/' target='_blank' class="sponsor">
          <img src="/assets/sponsors/placeos.png" />
          <span class="small">PlaceOS</span>
        </a>
      </div>
    </div>
  </div>

  <div class="row center">
    <div class="col s12">
      <div class="flag">
        <h3>Some of our CI runs here</h3>
      </div>
    </div>
  </div>

  <div class="row">
    <div class="col s12">
      <div class='sponsors-list'>
        <a href='https://developer.arm.com/solutions/infrastructure/works-on-arm' target='_blank' class="sponsor">
          <img src="/assets/sponsors/woa.png" />
          <span class="small">Works on Arm</span>
        </a>
      </div>
    </div>
  </div>

  <hr class="fullwidth">
  <div class="row">
    <div class="col s12">
      <h2>Articles from our blog</h2>
      {% assign articles = site.posts %}
      {% for post in articles limit: 3 %}
      {% include blog_row.html post=post %}
      {% endfor %}
      <p><a href="/blog">More articles</a></p>
    </div>
  </div>

  <div class="row">
    <div class="col s12">
      <h2>Release Notes</h2>
      <table class="bordered no-underline">
        <tbody>
          {% assign releases = site.releases | reverse %}
          {% for post in releases limit: 10 %}
          <tr>
            <td></td>
            <td><a href="{{ post.url }}">
                {{ post.title }}
              </a></td>
            <td>{{ post.date | date_to_string }}</td>
            {% endfor %}
        </tbody>
      </table>
      <p><a href="/blog#release_notes">More release notes</a></p>
    </div>
  </div>

  <div class="row center">
    <div class="col s12">
      <div class="flag">
        <h3>Community channels</h3>
        <a href="/community">Show all</a>
      </div>
    </div>
  </div>

  <div class="row">
    <div class="col s12">
      <div class='row community-list center'>
        <div class="col s12 m12 l3">
          <a href='https://github.com/crystal-lang/crystal/' target='_blank' class="item">
            <span class="small">Code repository</span>
            <i class="extra-icons github"></i>
            <span class="with_icon">crystal-lang/crystal</span>
          </a>
        </div>
        <div class="col s12 m12 l3">
          <a href='https://forum.crystal-lang.org' target='_blank' class="item">
            <span class="small">General discussion</span>
            <i class="material-icons">forum</i>
            <span class="with_icon">forum.crystal-lang.org</span>
          </a>
        </div>
        <div class="col s12 m12 l3">
          <a href='https://gitter.im/crystal-lang/crystal' target='_blank' class="item">
            <span class="small">Chat room</span>
            <i class="extra-icons gitter"></i>
            <span class="with_icon">crystal-lang/crystal</span>
          </a>
        </div>
        <div class="col s12 m12 l3">
          <a href='https://twitter.com/CrystalLanguage' target='_blank' class="item">
            <span class="small">General announcements and events</span>
            <i class="extra-icons twitter"></i>
            <span class="with_icon">@CrystalLanguage</span>
          </a>
        </div>
      </div>
    </div>
  </div>

</div>

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