Anvil Alternative

PDF Form Filling With a Human-in-the-Loop

Anvil is an API-first platform for generating and filling PDFs programmatically. It's great for fully automated workflows where no human review is needed: template-based document creation, e-signature packets, and bulk PDF filling via REST API. But many teams need a human to review, correct, or complete the form before submission. SimplePDF gives you that step: an embeddable editor where users see the actual PDF, fill in what automation missed, and submit. SimplePDF also supports programmatic filling via agent API endpoints, so you can pre-fill a PDF with data from your system and then hand it to a user for review and completion.

What you get with SimplePDF

A visual editor, not just an API

Anvil fills PDFs headlessly - there's no UI for the end user. SimplePDF gives users a visual editor where they can review and complete the form before submission.

Flat-rate pricing

Anvil charges per API call. SimplePDF is $99/mo with unlimited submissions. No per-document costs that scale with usage.

No template setup required

Anvil requires you to create templates and map fields before filling. SimplePDF auto-detects fields in any PDF - just point to a document and go.

Embeddable in one line

Anvil is API-only. SimplePDF embeds as a single iframe, giving your users a complete PDF editing experience inside your app.

Feature Comparison

Feature	Anvil	SimplePDF
Programmatic PDF filling	Yes (REST API)	Yes (agent API)
Visual PDF editor	No	Yes
Human-in-the-loop review	No	Yes
Form field auto-detection	No (template-based)	Yes
E-signatures	Yes (Etch signing)	Yes (draw, type, upload)
Template-based generation	Yes	No
Embeddable UI	No	Yes (one iframe)
Webhooks	Yes	Yes
White-label	No	Yes
BYOS	No	Yes (S3 & Azure)
Client-side processing	No (server-side)	Yes (in-browser)
Pricing	Per API call	From $99/mo (flat rate)

Integration Comparison

Anvil PDF fill API

const response = await fetch(
  'https://app.useanvil.com/api/v1/fill',
  {
    method: 'POST',
    headers: {
      Authorization: `Basic ${apiKey}`,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      title: 'My Document',
      data: {
        field1: 'value1',
        field2: 'value2'
        // Map every field manually
      }
    })
  }
);

SimplePDF (with human review)

<iframe
  src="https://yourcompany.simplepdf.com/editor"
  width="100%"
  height="800px"
/>

Where Anvil is the better fit

You need fully automated PDF generation and filling with no human interaction
You need template-based document creation at scale
You need Etch signing packets (multi-document, multi-signer workflows)
You need server-side PDF manipulation (merge, append, watermark) via API
Your workflow is entirely programmatic with no end-user-facing UI needed

Which SimplePDF product fits?

Embed

For teams that need users to review and complete pre-filled PDFs. The iframe editor can load a PDF with pre-filled data, letting users verify and add what's missing.

Learn about Embed

Portal

For non-technical teams who need to collect filled PDFs without API integration. Share a link, users fill the form, you get the completed document.

Learn about Portal

PDF-to-Web-Forms

Convert PDFs into web forms automatically. A no-code alternative to Anvil's template system for collecting form data without API integration.

Learn about PDF-to-Web-Forms

Got any questions?

Can Anvil show users the PDF before submitting?

Anvil is an API-first platform. It fills PDFs programmatically without showing the document to end users. If you need users to see, review, or edit the PDF before submission, you need a visual editor like SimplePDF.

What is the difference between Anvil and an embeddable PDF editor?

Anvil is a headless API for generating and filling PDFs programmatically. An embeddable PDF editor like SimplePDF provides a visual interface where end users interact with the document directly. Anvil is for automation; SimplePDF is for human-in-the-loop workflows.

Is there an Anvil alternative with a visual editor?

Yes. SimplePDF provides both a visual editor (embeddable via iframe) and programmatic API endpoints for PDF filling. This means you can pre-fill PDFs via API and then let users review and complete them in the visual editor.

Anvil vs SimplePDF for PDF form filling?

Choose Anvil if your workflow is fully automated (no human review needed) and you need template-based document generation. Choose SimplePDF if you need users to see, fill, or review PDFs before submission, or if you want to embed a PDF editor in your app.

PDF Editor Alternatives

Ready to try it?

See how SimplePDF adds a visual layer to PDF form filling.

Try the editor See pricing