Fillable vs Nitro PDF Pro

Fillable is a web and API service for turning PDFs into guided client workflows. It detects fields, accepts document uploads, supports signatures, and creates shareable completion links that clients can use without an account or app. Browser tools can fill, create, sign, merge, split, compress, convert, and OCR PDFs. Guided packs collect completed forms and requested documents; the free plan includes one active pack, all library templates and official forms, and a test API key. Teams can import existing PDFs, apply field validation and conditional logic, and export PDF or JSON. The REST API parses PDF fields and text into JSON and fills existing form fields. Each key allows 100 requests per calendar day, counting authenticated calls that succeed or return errors. It does not create PDFs from HTML, convert file formats, or add fields to flat PDFs. Core tools run in the browser; server-side conversions upload files and delete them afterward. Paid monthly plans start at $9/mo.

Nitro PDF Pro has no write-up on Specifiction yet; its figures are above.