SimplyFill vs Anvil: focused PDF filling or the full paperwork suite?
Anvil and SimplyFill both let you fill PDFs from your application data with an API call, but they're built around different bets. Anvil's bet is that you want one platform for all paperwork — webforms to collect data, workflows to route it, e-signatures to finish it, and a PDF API underneath. SimplyFill's bet is that you already have an application, and what you want is document generation as clean infrastructure: data in, filled PDFs out, nothing else to adopt.
Neither bet is wrong. The right one depends on how much of the paperwork lifecycle you want to outsource versus own.
At a glance
| SimplyFill | Anvil | |
|---|---|---|
| Scope | PDF filling API | Suite: PDF API, Webforms, Workflows, Etch e-sign, Document AI |
| Field setup | AI proposes semantic aliases from visible labels; you review with confidence scores | Document AI tags fields, including lines/boxes in flat PDFs; Document Editor for templates |
| API style | REST | REST and GraphQL |
| SDKs | Node.js, Python | Node.js/TypeScript, Python, C#, Java, plus React components |
| Multi-document output | Envelopes — one payload, a packet of PDFs | Workflows orchestrate multi-document processes |
| E-signatures | Sign-ready output for the e-sign tool you already use | Built in (Etch e-sign) |
| Hosted data collection | No — your app owns the UI | Webforms, mobile-friendly, embeddable |
| XFA forms | Auto-flattened on upload | Not prominently documented |
| Environments | Dev/staging/prod template versions with promotion | Test mode |
| Pricing model | Plan tiers — see pricing | Free tier, then pay-as-you-go ($0.10/PDF fill, $1.00/workflow submission, $1.50/e-sign packet) plus feature packs at $99–$425/mo (as of June 2026) |
Where Anvil is strong
Anvil has built a genuinely broad platform, and several pieces of it are best-in-class for what they do.
- The suite is real. Webforms, workflow routing, and embedded white-label e-signing are all first-party. If you need to collect data from end users, route it through approvals, sign it, and archive it — without building any of that UI — Anvil covers the whole arc.
- Document AI on flat PDFs. Anvil can detect fields in PDFs that have no native form fields at all, inferring boxes and lines from the page image. That's a hard problem and a real capability.
- Generous free tier. As of June 2026, Anvil's free plan includes unlimited templates and workflow submissions with pay-as-you-go API pricing past the starter credits. For a side project or a low-volume internal tool, you may never pay much.
- Wide SDK coverage. First-party libraries for Node, Python, C#, and Java, plus React components and a GraphQL API if that fits your stack.
If your team is small, has no front-end capacity to spare, and wants the data-collection UI handled too, Anvil is a strong pick.
Where SimplyFill is different
SimplyFill is intentionally narrow: it's the PDF-filling layer, built for teams whose application already owns the user experience.
- No platform adoption tax. With a suite, the integration pulls you toward its webforms, its workflow model, its signing ceremony. SimplyFill's surface area is a handful of REST endpoints — templates, mappings, generate — so the blast radius in your architecture stays small, and so does the cost of ever leaving.
- Mapping as the product, not a setup step. SimplyFill's AI reads each
field's visible label and context and proposes a semantic alias with a
confidence score and an evidence note. The resulting mapping is a versioned,
server-side object: your code sends
{ "fullName": "Jane Doe" }forever, even when the underlying form revision renames its internals. (More on the problem this solves in why PDF form fields have meaningless names.) - Envelopes without workflow machinery. When one event needs to produce a packet of documents, that's a single API call with N template references — not a workflow definition.
- Government-form reality. XFA forms are auto-flattened at upload, and output PDFs are flattened and sign-ready for whichever e-sign vendor you already use rather than assuming you'll switch to a bundled one.
- Environment promotion. Templates move dev → staging → production explicitly, so a mapping edit can't silently change what production renders.
Pricing
The models differ more than the prices. Anvil is usage-based: free to start, then $0.10 per PDF fill past your credits, with the AI Pack at $99/month and the Product Pack at $425/month unlocking programmatic Document AI and advanced signing respectively (as of June 2026 — check their pricing). Pure usage pricing is great at low volume and unpredictable at high volume: 50,000 fills a month is $5,000 before discounts.
SimplyFill uses plan tiers — current numbers on the pricing section. The comparison worth doing is at your projected volume, including the months after the project succeeds.
When to choose which
Choose Anvil if:
- You need hosted webforms, routing, and e-signing and don't want to build or integrate any of it.
- Your PDFs are flat scans with no form fields, where Anvil's Document AI detection earns its keep.
- Your volume is low enough that pay-as-you-go stays cheap.
Choose SimplyFill if:
- Your application already collects the data and owns the user experience — you want infrastructure, not a second platform.
- Your forms are field-heavy PDFs (especially government/XFA ones) where automated semantic mapping saves the most time.
- You want predictable plan pricing and per-environment template versioning as workflows scale.
The five-minute test
Both products let you start without a sales call. Take a representative form, run it through SimplyFill's quickstart, and compare the upload-to-first-filled-PDF experience directly — including how much of the field setup you had to do yourself.