Anvil PDF Generation API

Anvil PDF Generation API creates PDFs on demand from HTML and CSS or Markdown. Developers can set page dimensions and margins, add headers, footers and page numbers, use custom TTF fonts, and create fillable forms or variable-length documents. Markdown conversion uses a default theme, with an option to supply CSS. Anvil lists SDKs for C#/.NET, JavaScript, Python and TypeScript; Go, Java, PHP and Ruby are marked as coming soon. A Zapier integration can automate paperwork workflows, including filling PDFs or starting or pre-filling a Workflow. The cloud API lists SOC 2 and HIPAA compliance, and email support. Free mode is limited to UI use; API key access requires a credit card or upgrade. Test mode is free and unlimited on every plan, but test documents carry watermarks and use demo signatures. API PDF fill or generation costs $0.10 per use; enabling metered usage with a valid card provides 2,500 starter credits. Custom fonts must be TTF; OTF and WOFF are not supported.

Anvil offers PDF generation and filling through an API, with document controls, SDKs and a Zapier integration. Check the API access requirements, per-use charge and font format limits before adopting it.

Anvil PDF Generation API is presented for developers and agents who need to generate or fill PDFs programmatically. Technical teams working with high PDF volumes may also consider the listed AI Pack.

Overview

Anvil PDF Generation API converts HTML, CSS, or Markdown into PDFs on demand, with form filling and workflow automation alongside generation. It is best suited to developers and technical teams embedding document production in applications. Its flexibility is compelling, but API charges, card requirements and font restrictions deserve a close look before adoption.

Key features

HTML-to-PDF supports full CSS, page dimensions and margins, headers, footers, page numbers, and fillable forms. That control helps teams build branded documents and adapt layouts to variable-length content rather than force every output into a fixed page design. Custom fonts must be TTF; OTF and WOFF are unsupported, so teams using those formats may need to change their assets.

Markdown provides a more structured input path, including tables and images. It uses a default theme, but callers can supply CSS to shape the result. JSON data and dynamic, variable-length documents support outputs assembled from changing inputs, while reusable forms and data merge suit recurring paperwork.

SDKs are available for C#/.NET, JavaScript, Python, and TypeScript; Go, Java, PHP, and Ruby are marked as coming soon. Zapier can automate paperwork tasks such as filling a PDF or starting or pre-filling an Anvil Workflow. Test mode is free and unlimited on every plan, but test documents carry watermarks and demo signatures. Anvil lists SOC 2 and HIPAA compliance and says signed documents are encrypted with a 2048 RSA private key stored in a secure Hardware Security Module inaccessible to its developers.

Pricing

The Free plan costs nothing and allows 2 users, but is UI only. API key access requires adding a credit card or upgrading; enabling metered usage with a valid card provides 2,500 starter credits. The free tier is useful for trying the interface, while API evaluation can incur charges once credits are used.

API PDF fill or generation costs $0.10, paid once, billed at $0.10 per PDF Fill/Generation. Paid API use requires a valid credit card, and bulk quantities start at 25,000+. Test requests do not count against quotas or incur charges. This pay-as-you-go route suits teams with variable or modest usage, but costs scale with each live PDF.

The AI Pack costs $99 a month, billed $99/mo, for 5 users. It adds programmatic Document AI, a 50-page limit per AI-tagged PDF, and a higher rate limit of 40/s; it is aimed at technical teams handling high PDF volumes. The Product Pack costs $425 a month, billed $425/mo, also for 5 users, and includes AI Pack features plus white labeling and advanced signing features. It is the more relevant tier for teams needing those additions, but costs substantially more than metered generation alone.

Enterprise has custom pricing and unlimited users, with SSO, HIPAA, DPA, priority support, and customer success. It fits organizations that need those controls and support. The plans differ in users and features; the per-use API charge remains a separate cost consideration.

Platforms

Anvil is a cloud service with API and web access, plus email support. Its published SDKs cover C#/.NET, JavaScript, Python, and TypeScript. The API-centric design favors teams able to integrate software into their own workflows rather than people seeking a standalone PDF editor.

Who it's for

Choose Anvil when an application needs on-demand PDFs from structured or designed inputs, particularly if documents need variable length, fillable fields, or workflow automation. It is less suitable for teams that need OTF or WOFF fonts, want API access without a card, or prefer a fixed-cost model without per-document charges.

Pros and cons

• Pros: HTML/CSS control and Markdown input cover both designed layouts and structured content.
• Pros: Fillable forms, reusable forms, data merge, and Zapier workflows extend the API beyond simple conversion.
• Pros: Unlimited free test requests allow evaluation without consuming quotas or incurring charges.
• Cons: Live API use requires a valid credit card and costs $0.10 per PDF fill or generation.
• Cons: Custom fonts are limited to TTF, excluding OTF and WOFF.
• Cons: Free access is UI only for 2 users; the paid packs have 5-user limits.

Alternatives

CraftMyPDF is worth considering for a smaller free allowance: its Free plan includes 50 PDFs or images per month, 3 templates, and REST API, Zapier, Make.com, and Bubble.io integrations. DocRaptor offers a free plan capped at 5 documents per month and a Basic plan at $15 a month, making it an option for readers comparing a low-priced monthly tier. Carbone is another freemium API option, with a free cloud plan and support for self-hosted and desktop platforms.

PDF24 Compare PDF is a free option across web, desktop, and mobile platforms. Wondershare PDFelement offers paid plans across web, desktop, and mobile platforms. iText pdfOptimizer has API and self-hosted availability with a free plan and trial. PDF4me Merge & Split offers a limited free API tier and one-time call packs. ReportLab provides a free open-source PDF generation library for commercial use.

Browse PDF Creation Software or Document Template Management Software for more options.

Verdict

Anvil is a strong fit for developers who need flexible PDF generation, form filling, and paperwork workflows in one API. Its layout controls, dynamic document support, and Zapier integration make it more capable than a basic converter. Look elsewhere if your existing fonts are OTF or WOFF, API use cannot rely on a credit card, or per-document pricing is a poor match for your volume.