Building an e-signature SaaS with Laravel 13 and React 19

The core requirement wasn't drawing a signature. It was evidence. Every action on a document is written to an append-only audit history, and the finished agreement comes with an audit certificate. If a signature is ever questioned, the record is there.

The application is Laravel 13 on PHP 8.4, with a React 19 and TypeScript front end rendered through Inertia. That gives a single-page app experience without maintaining a separate API layer for the UI. Tailwind CSS handles the interface and MySQL stores the data.

Queues and scheduled jobs handle the slow work, such as sending invitations and generating PDFs, so the interface stays fast.

There's no open sign-up. Platform admins create companies and invite their owners; owners invite their own team. Each company only ever sees its own agreements. Authentication uses Laravel Fortify with verified email, TOTP two-factor authentication and recovery codes.

Senders place signature, date and text fields directly on the document in the browser, using PDF.js to render the pages. Signers then follow a protected journey that only shows them what they need to complete.

Final documents are produced by a Python worker using pypdf, ReportLab and Pillow. Given the same inputs it produces the same output, which is what you want for documents that might end up as evidence. It generates both the completed PDF and its audit certificate.

The project ships with a reproducible Docker development stack (PHP 8.4, MySQL 8.4, Node 24, a queue worker, the scheduler and Mailpit for email) and an automated test suite, so changes can be made with confidence long after launch.