Joansaro Contratos

Contract e-signature system: field editor, digital signing and certified PDF output.

Code

E2E tests passing

17/17

Tamper evidence

SHA-256

Embedded signature fonts

About this project

Complete contract-signing platform built with Next.js 15 and Prisma on SQLite, from a custom design system. The owner creates documents (blank, template or uploaded PDF), places signature/date/text fields by dragging and resizing over the document, and sends a unique link to the signer. The client signs by drawing on canvas or typing with real calligraphic fonts, and both parties download a server-generated PDF with a Certificate of Completion page: timestamps, IP, device, SHA-256 hash and the full audit trail.

01. Problem

A signing flow has many moving parts: document states, a visual field editor, a public signer flow, and verifiable evidence of what was signed, when and by whom.

02. Solution

Next.js Server Actions as the single API layer, a Draft→Sent→Viewed→Signed/Declined state machine with an event timeline, a drag-and-drop editor with percentage coordinates, tokenized signer links, and pdf-lib PDF generation embedding the real signature fonts.

03. Outcome

Full cycle verified with a Playwright E2E suite (17/17): create, prepare, send, sign in another session and download the certified PDF with hash and IP.

Gallery

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