Anvil PDF Generation API

Overview

Anvil PDF Generation API turns HTML, CSS, Markdown, and JSON data into PDFs for applications and automated paperwork. It is best suited to developers who need both document generation and form workflows in one service. Its strongest case is flexible, dynamic output; per-use API charges and a narrow custom-font format may complicate adoption.

Key features

HTML-to-PDF gives developers control over CSS, page dimensions, margins, headers, footers, page numbers, and fillable form fields. That makes it a good fit for branded or variable-length documents rather than simple printouts. Custom fonts must be TTF: OTF and WOFF are not supported, which can force font changes in an existing design system.

Markdown offers a more structured route, including tables and images. It starts with a default theme, though callers can supply CSS to adapt the presentation. Support for dynamic, variable-length documents and JSON data is useful when output changes with each request, while reusable forms can serve recurring paperwork.

SDKs are available for C#/.NET, JavaScript, Python, and TypeScript; Go, Java, PHP, and Ruby are marked as coming soon. Zapier can connect PDF filling with paperwork workflows, including starting or pre-filling an Anvil Workflow. Anvil lists SOC 2 and HIPAA compliance. It says signed documents are encrypted using a 2048 RSA private key kept in a secure Hardware Security Module that its developers cannot access.

Pricing

The Free plan costs nothing and supports two users, but is UI-only until a credit card is added or the account is upgraded to enable API key access. Enabling metered usage with a valid credit card provides 2,500 starter credits. API PDF fill or generation then costs $0.10, paid once; paid API use requires a valid credit card, and bulk quantities start at 25,000+.

The AI Pack is $99 a month, billed $99/mo, for five users. It adds programmatic Document AI, a limit of 50 pages per AI-tagged PDF, and a higher rate limit of 40/s. It is the relevant step up for technical teams handling high PDF volumes, but it does not replace the per-use charge for PDF filling or generation.

The Product Pack is $425 a month, billed $425/mo, for five users. It includes AI Pack features, white labeling, and advanced signing features, making the higher price relevant when those capabilities matter. Enterprise has custom pricing and unlimited users, with SSO, HIPAA, DPA, priority support, and customer success.

Every plan includes free, unlimited test mode. Test requests do not count toward quotas or incur charges, but generated documents are watermarked and use demo signatures, so this is for evaluation rather than production output. There is no free trial.

Platforms

Anvil is a cloud service with API and web access. Email support is available, and Zapier provides an integration path for paperwork automation.

Who it's for

Choose Anvil if you are building an application or automated workflow that needs configurable PDF output, fillable forms, and programmatic access. It is less suitable if your design depends on OTF or WOFF fonts, or if you want API access without a credit card and metered billing.

Pros and cons

• Pros: HTML/CSS layout controls, Markdown input, JSON data, and variable-length documents cover several generation needs in one API.
• Pros: Unlimited free test mode lets teams exercise requests without consuming quotas or incurring charges.
• Pros: Fillable forms, reusable forms, Zapier, and listed SOC 2 and HIPAA compliance make it relevant to paperwork workflows.
• Cons: Production API use is metered at $0.10, paid once and requires a valid credit card.
• Cons: Free-plan API access requires adding a card or upgrading, despite the plan's two-user allowance.
• Cons: Custom fonts are limited to TTF, and test documents carry watermarks and demo signatures.

Alternatives

For a broader comparison, browse Document Template Management Software and PDF Creation Software.

Consider Docxtemplater if you want an open-source option with a free tier or need its broader platform coverage, including self-hosted and mobile environments. Carbone is another freemium option, with a free trial and self-hosted platform support. Documentero may suit teams that want a stated free allowance of 50 documents, three templates, and unlimited pages and fields. Legito is worth considering when document lifecycle management, customizable workflows, approvals, and electronic signatures are the priority.

PDFMonkey offers a free tier capped at 20 documents per month, with one-day retention and a 30-second generation limit. Docassemble is a free, self-hosted alternative, though hosting typically costs $10–$40 per month or more depending on performance, availability, and support needs. Fluent by Apryse is a paid option whose entry-level packages start at $1,500, with pricing varying by features, document volume, and deployment. Marq is web-only and has a free plan limited to one user, 25 MB of cloud storage, and three projects.

Verdict

Anvil is a strong fit for developers who need on-demand PDFs, fillable forms, and automated paperwork in a single cloud API. Its free test mode lowers evaluation risk, but production usage is metered and the Free plan gates API keys behind a card or upgrade. Look elsewhere if you need OTF or WOFF fonts, or prefer a self-hosted or flat-cost approach.