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18<p>Design, implement, consume, and document APIs with tools and libraries that work with simple API definitions.</p>
19<h2 class="anchor anchorTargetStickyNavbar_Vzrq" id="design">Design<a href="#design" class="hash-link" aria-label="Direct link to Design" title="Direct link to Design" translate="no">​</a></h2>
20<p>Use the <a class="" href="/editor">Live Editor</a> or any text editor to design your API using the simple <a class="" href="/define/fsd">FSD format</a>, or convert an <a class="" href="/define/swagger">OpenAPI</a> spec to FSD.</p>
21<p>Each method of your API has a name and a corresponding HTTP path. Clients POST the JSON request and receive a JSON response. Make your API less RPC-ish and more RESTful by adding <a class="" href="/define/fsd#attributes">attributes</a> to your FSD methods and data fields.</p>
22<p>Commit your API definition to source control for revision tracking and peer review. Run <a class="" href="/generate">command-line tools</a> from your automated builds to validate the syntax and ensure that generated code and documentation stays up-to-date.</p>
23<h2 class="anchor anchorTargetStickyNavbar_Vzrq" id="implement">Implement<a href="#implement" class="hash-link" aria-label="Direct link to Implement" title="Direct link to Implement" translate="no">​</a></h2>
24<p>Facility <a class="" href="/generate/csharp">generates a C# interface</a> with one method for each method of your API.</p>
25<p>You write a C# class that implements that interface and then <a class="" href="/generate/aspnet">integrate that class</a> into an ASP.NET app. Facility takes care of the HTTP mapping so you can focus on the implementation logic.</p>
26<p>Your C# class is easily unit tested, encourages good separation of concerns, and is more flexible than a hand-coded controller. Edit the FSD and regenerate the code to rapidly add new features to your API.</p>
27<p>Alternatively, <a class="" href="/define/swagger">convert your FSD to OpenAPI</a> and find support for your favorite API framework among the many <a href="https://swagger.io/tools/" target="_blank" rel="noopener noreferrer" class="">supported tools</a>.</p>
28<h2 class="anchor anchorTargetStickyNavbar_Vzrq" id="consume">Consume<a href="#consume" class="hash-link" aria-label="Direct link to Consume" title="Direct link to Consume" translate="no">​</a></h2>
29<p>Facility generates client libraries in <a class="" href="/generate/csharp">C#</a> and <a class="" href="/generate/javascript">JavaScript/TypeScript</a>.</p>
30<p>Publish to <a href="https://www.nuget.org/" target="_blank" rel="noopener noreferrer" class="">NuGet</a> and <a href="https://www.npmjs.com/" target="_blank" rel="noopener noreferrer" class="">npm</a> to make it easy for clients to use your API. The generated code is designed to avoid breaking changes even as your API evolves.</p>
31<p>Do not repeat yourself: The C# client library and the server implementation use the same C# interfaces and classes. Generate TypeScript to leverage type information while maintaining JavaScript compatibility.</p>
32<p>To build client libraries for other languages and frameworks, <a class="" href="/define/swagger">convert your FSD to OpenAPI</a> and use any of the <a href="https://swagger.io/tools/" target="_blank" rel="noopener noreferrer" class="">supported tools</a>.</p>
33<h2 class="anchor anchorTargetStickyNavbar_Vzrq" id="document">

33Document<a href="#document" class="hash-link" aria-label="Direct link to Document" title="Direct link to Document" translate="no">​</a></h2>
34<p><a class="" href="/generate/markdown">Generate Markdown documentation</a> for your API.</p>
35<p>Push the documentation to <a href="https://github.com/" target="_blank" rel="noopener noreferrer" class="">GitHub</a> for easy reading at your GitHub repository, or use the Markdown support of <a href="https://pages.github.com/" target="_blank" rel="noopener noreferrer" class="">GitHub Pages</a> to display the documentation on your project website.</p>
36<p>You can also <a class="" href="/define/swagger">convert your FSD to OpenAPI</a> and use <a href="https://swagger.io/swagger-ui/" target="_blank" rel="noopener noreferrer" class="">Swagger UI</a>.</p></div><footer class="theme-doc-footer docusaurus-mt-lg"><div class="row margin-top--sm theme-doc-footer-edit-meta-row"><div class="col noPrint_WFHX"><a href="https://github.com/FacilityApi/FacilityApi.github.io/tree/master/docs/README.md" target="_blank" rel="noopener noreferrer" class="theme-edit-this-page"><svg fill="currentColor" height="20" width="20" viewBox="0 0 40 40" class="iconEdit_Z9Sw" aria-hidden="true"><g><path d="m34.5 11.7l-3 3.1-6.3-6.3 3.1-3q0.5-0.5 1.2-0.5t1.1 0.5l3.9 3.9q0.5 0.4 0.5 1.1t-0.5 1.2z m-29.5 17.1l18.4-18.5 6.3 6.3-18.4 18.4h-6.3v-6.2z"></path></g></svg>Edit this page</a></div><div class="col lastUpdated_JAkA"></div></div></footer></article><nav class="docusaurus-mt-lg pagination-nav" aria-label="Docs pages"><a class="pagination-nav__link pagination-nav__link--next" href="/why"><div class="pagination-nav__sublabel">Next</div><div class="pagination-nav__label">Why Facility?</div></a></nav></div></div><div class="col col--3"><div class="tableOfContents_bqdL thin-scrollbar theme-doc-toc-desktop"><ul class="table-of-contents table-of-contents__left-border"><li><a href="#design" class="table-of-contents__link toc-highlight">Design</a></li><li><a href="#implement" class="table-of-contents__link toc-highlight">Implement</a></li><li><a href="#consume" class="table-of-contents__link toc-highlight">Consume</a></li><li><a href="#document" class="table-of-contents__link toc-highlight">Document</a></li></ul></div></div></div></div></main></div></div></div><footer class="theme-layout-footer footer footer--dark"><div class="container container-fluid"><div class="footer__bottom text--center"><div class="footer__copyright">Copyright © 2026 Ed Ball. Built with Docusaurus.</div></div></div></footer></div>
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