Anvil

Anvil is a document workflow API combining PDF template filling, electronic signature collection, and workflow orchestration — enabling agents to generate filled PDFs from structured data, send them for signature, and retrieve the completed documents in a single integrated workflow. The combination of document generation and signature collection in one API surface reduces integration complexity compared to maintaining separate PDF generation and e-signature services.

Authentication uses API keys for the REST and GraphQL APIs. Keys are organization-scoped. Anvil's pricing model is usage-based — teams should monitor API call volumes for cost predictability in high-volume document generation workflows.

Documentation covers the PDF filling API, e-signature flows, and GraphQL schema clearly. The template setup documentation — explaining how to define fillable PDF fields — is important for teams setting up their first Anvil integration. Teams evaluating Anvil versus Dropbox Sign or DocuSign for document workflows should compare the integrated PDF generation capability, which is distinctive to Anvil versus pure e-signature platforms.

The API covers PDF filling (populating PDF templates with structured data), e-signature (Etch E-Sign for embedded or email-based signing), and Weld (workflow builder for multi-step document processes). Agents can fill PDF templates with applicant or customer data, attach them to signature requests, track signing status, and retrieve signed documents. The GraphQL API provides the primary programmatic interface for workflow management.

Reliability is appropriate for a document workflow platform. Anvil handles PDF rendering, signature collection infrastructure, and document storage. Teams with mission-critical document workflows should implement webhook-based status monitoring and appropriate error handling for PDF generation failures on complex templates.