/HomeHugoBlox Kit (https://hugoblox.com)enWed, 12 Aug 2026 00:00:00 +0000/media/icon_hu_8b792fc0bcdf6699.png//about/Wed, 12 Aug 2026 00:00:00 +0000/about/<p>Zugferdchen 🐴 is a free, anonymous debugging tool for electronic invoices, built around the <a href="https://www.mustangproject.org/" target="_blank" rel="noopener">Mustang (Mustangproject)</a> ZUGFeRD / Factur-X / XRechnung validator.</p> <p>No account, no login, no API key. Uploaded invoices live only for the duration of the request that carries them &ndash; invoice bytes, extracted XML and finding text are never written to disk and never logged. The only durable state is an anonymized <a href="/app/stats">usage counter</a>.</p> <h2 id="rate-limits">Rate limits</h2> <p>Six actions per minute per IP. An <em>action</em> is a validation or an XML extraction; loading a page, reloading it, or reading the stats costs nothing.</p> <h2 id="api">API</h2> <p>Two stateless, unauthenticated endpoints:</p> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-bash" data-lang="bash"><span class="line"><span class="cl">curl -X POST -F <span class="s2">&#34;file=@invoice.pdf&#34;</span> https://www.zugferdchen.de/api/v1/validate </span></span><span class="line"><span class="cl">curl -X POST -F <span class="s2">&#34;file=@invoice.pdf&#34;</span> https://www.zugferdchen.de/api/v1/xml </span></span></code></pre></div><p><code>validate</code> returns the verdict, standard/profile/version and findings. <code>xml</code> returns the embedded CII as both a nested JSON tree and base64 XML.</p> <h2 id="try-it-here">Try it here</h2> <p>The same widget the home page uses, embedded in a plain Markdown page via a shortcode:</p> <link rel="stylesheet" href="/static/css/embed.css" /> <script type="module" src="/static/vendor/datastar.js"></script> <div class="flyferd" data-signals="{status: 'idle', filename: ''}"> <h2 class="font-display text-3xl sm:text-4xl font-bold tracking-tight leading-[1.05]">Validate an invoice</h2> <form method="dialog" enctype="multipart/form-data" class="mt-8 mx-auto max-w-2xl" data-on:submit__prevent="$filename && ($status = 'validating', @post('\/app\/validate', {contentType: 'form'}))" > <label class="dropzone relative flex flex-col items-center justify-center gap-3 px-6 py-12 text-center cursor-pointer" > <svg class="size-8 text-[var(--color-indigo)]" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.6" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true" > <path d="M12 15V3m0 0L8 7m4-4 4 4" /> <path d="M4 15v4a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2v-4" /> </svg> <span class="font-medium"> <span data-show="!$filename">Drag an invoice here, or click to choose</span> <span class="code text-[var(--color-ink)]" data-show="$filename" data-text="$filename"></span> </span> <span class="eyebrow">PDF or XML · up to 20 MB</span> <input type="file" name="file" accept=".pdf,.xml,application/pdf,application/xml,text/xml" class="absolute inset-0 h-full w-full cursor-pointer opacity-0" data-on:change="$filename = evt.target.files.length ? evt.target.files[0].name : ''" /> </label> <div class="mt-5 flex items-center justify-center gap-3"> <button type="submit" class="btn btn-lg" data-attr:disabled="!$filename || $status === 'validating'" > <span data-show="$status !== 'validating'">Validate invoice</span> <span data-show="$status === 'validating'">Validating…</span> </button> <button type="reset" class="btn btn-outline btn-lg" data-show="$filename" data-on:click="$filename = ''; $status = 'idle'" > Clear </button> </div> </form> <div data-show="$status === 'validating'" class="mt-10 flex items-center justify-center gap-3 text-[var(--muted-foreground)]" > <span class="inline-block size-4 rounded-full border-2 border-[var(--border)] border-t-[var(--color-indigo)] animate-spin" ></span> <span class="code text-sm">Running Mustang validation…</span> </div> <div id="result" aria-live="polite"></div> </div>