JavaScript file upload form
Build a file upload form with plain JavaScript and no upload API. Post the raw FormData with fetch so the browser sets the multipart boundary, and the file lands in your inbox with the other fields. Copy the code and add your access key.
How to build it
- Create a form in your Formpaste dashboard and copy its access key.
- Connect Storage in the dashboard so the form can accept uploads.
- Copy the form and script above, add your access key, then publish.
Prompt for your AI coding agent
Add a Formpaste file upload form to my page with vanilla JavaScript. Use a real form with enctype multipart/form-data and a file input, plus a submit listener that POSTs new FormData(form) directly (not URLSearchParams) to https://api.formpaste.com/submit with a hidden access_key input. Do not build an upload endpoint of my own.Or connect the Formpaste MCP server to Claude Code, Codex, Cursor, Claude Desktop, VS Code, or any mcp-remote client. See the setup guide.
JavaScript gotchas
A vanilla JavaScript contact form is plain HTML plus a submit listener. Point the form at Formpaste, add a script that calls preventDefault and posts the FormData with fetch, and the visitor stays on the page. No framework, no build step, no backend.
It is a form plus a listener
Keep the real form markup with an action pointing at the Formpaste endpoint, then add a submit listener that calls preventDefault and posts with fetch. There is no framework and nothing to install, so the same snippet works in a static site, a CMS template, or a hand-written page.
Progressive enhancement is free
Because the markup is a real form with an action, it still submits if your script fails to load or JavaScript is switched off. The listener is an upgrade that keeps the visitor on the page, not a requirement.
Post FormData, not a hand-built object
Build the body with new FormData(form) so every field comes along by name, including the hidden access_key. Wrap it in URLSearchParams for a normal text form, or post the FormData directly when the form has a file input.
Handle the response yourself
The endpoint returns JSON (success, message, id). Await the fetch and show your own success or error message, then call form.reset(). Or set a redirect URL in the dashboard and let the plain form post do the work with no script at all.
What to get right
A file means multipart, not urlencoded
As soon as the form has a file input, it must post multipart form data. The generated code sets enctype and sends the raw FormData, so the file rides along with the other fields. No upload endpoint of your own is needed.
The upload is client to Formpaste, direct
The browser posts the file straight to Formpaste, so your app never buffers or parses the upload. That sidesteps serverless body-size and runtime limits entirely.
Set expectations on size and type
Tell people what you accept. File uploads are a Pro feature; connect Storage in the dashboard first, and keep the input honest about accepted types and size.
How it works
Three simple steps for form submissions to land in your email inbox.
Create your form, set your form's action URL to Formpaste's endpoint, and add your access key.
Create your form
Sign up, verify your email, and create an access key in your dashboard.
Copy the code
Paste the snippet above into your project. Pick CSS or Tailwind to match your site.
<form id="form" action="https://api.formpaste.com/submit" method="POST" enctype="multipart/form-data" class="mx-auto flex w-full max-w-md flex-col gap-4 rounded-xl border border-gray-200 bg-white p-6 shadow-sm dark:border-gray-800 dark:bg-gray-950">
<input type="hidden" name="access_key" value="YOUR_ACCESS_KEY_HERE">
<label class="flex flex-col gap-1.5 text-sm font-medium text-gray-900 dark:text-gray-100">Name
<input type="text" name="name" required class="rounded-md border border-gray-300 bg-white px-3 py-2 text-sm text-gray-900 shadow-sm outline-none focus-visible:ring-2 focus-visible:ring-gray-900 dark:border-gray-700 dark:bg-gray-900 dark:text-gray-100 dark:focus-visible:ring-gray-100" />
</label>
<label class="flex flex-col gap-1.5 text-sm font-medium text-gray-900 dark:text-gray-100">Email
<input type="email" name="email" placeholder="you@example.com" required class="rounded-md border border-gray-300 bg-white px-3 py-2 text-sm text-gray-900 shadow-sm outline-none focus-visible:ring-2 focus-visible:ring-gray-900 dark:border-gray-700 dark:bg-gray-900 dark:text-gray-100 dark:focus-visible:ring-gray-100" />
</label>
<label class="flex flex-col gap-1.5 text-sm font-medium text-gray-900 dark:text-gray-100">File
<input type="file" name="file" required class="rounded-md border border-gray-300 bg-white px-3 py-2 text-sm text-gray-900 shadow-sm outline-none focus-visible:ring-2 focus-visible:ring-gray-900 dark:border-gray-700 dark:bg-gray-900 dark:text-gray-100 dark:focus-visible:ring-gray-100" />
</label>
<label class="flex flex-col gap-1.5 text-sm font-medium text-gray-900 dark:text-gray-100">Message
<textarea name="message" class="min-h-28 rounded-md border border-gray-300 bg-white px-3 py-2 text-sm text-gray-900 shadow-sm outline-none focus-visible:ring-2 focus-visible:ring-gray-900 dark:border-gray-700 dark:bg-gray-900 dark:text-gray-100 dark:focus-visible:ring-gray-100"></textarea>
</label>
<button type="submit" class="w-full rounded-md bg-gray-900 px-4 py-2 text-sm font-medium text-white shadow-sm transition-colors hover:bg-gray-800 disabled:opacity-60 dark:bg-white dark:text-gray-900 dark:hover:bg-gray-200">Upload</button>
</form>
<script>
const form = document.getElementById("form");
form.addEventListener("submit", async (e) => {
e.preventDefault();
await fetch("https://api.formpaste.com/submit", { method: "POST", body: new FormData(form) });
form.reset();
});
</script>Add your access key
Replace the placeholder with your access key to start receiving submissions.
<input type="hidden" name="access_key" value="YOUR_ACCESS_KEY_HERE">JavaScript file upload form FAQ
Paste a form. Get submissions.
Instantly without setting up any backend, servers or databases. 250 submissions/mo free - no credit card.