B2B SaaS · Document automation · Under NDA

Personalized documents generated, signed and tracked, at about 22 per second.

Personalized documents were produced one at a time: copy a row from a spreadsheet, paste into a template, export, rename, email, chase the signature. We built a multi-tenant platform that handles the whole document lifecycle, from template to signed PDF.

Client work under NDA. We show the problem, the system and the results, but not the client's name or screenshots. More detail is available on a call.

Measured throughput~22 docs/sImplementation-specific result; workload affects throughput.
  • Nuxt
  • NestJS
  • Rust
  • Prisma
  • PostgreSQL
  • DynamoDB
  • Redis
  • BullMQ
  • S3
— 01 The approach

How we framed it.

A template is a PDF plus a visual field layout. Authors drag fields onto a canvas, or let AI detect the fillable areas, with every AI-placed field held for human approval. Data binds from datasets, live spreadsheets or public forms, a high-performance rendering engine generates the PDFs, and e-signatures, delivery and status tracking close the loop.

— 02 How it works

Inside the build.

Visual template editor

25 field types across fillable fields, static elements and dataset-bound fields, with alignment guides, undo and redo, snippet libraries, watermarks and custom fonts.

AI field detection with human approval

A parsing service reads the page geometry and a model decides which regions are fillable. Every AI-placed field blocks saving until a person approves it.

Four ways to bind data

Uploaded datasets, a live-connected spreadsheet that generates documents for new rows on a schedule, public form links, or one form fanning out to several templates.

Rust rendering engine

A hand-rolled PDF writer generates, fills, flattens and repairs documents. Batches run in parallel, bringing per-document cost from about 200 to about 46 milliseconds.

Full document life

A searchable library, share links with expiry, exports to spreadsheets and cloud drives, branded email delivery and a complete e-signature flow with one-time-code verification.

— 03 Outcomes

What shipped.

  • About 200 milliseconds for a single document
  • A 100-document batch in about 4.5 seconds
  • AI-placed fields always approved by a person
  • Rate-limited and quota-metered per workspace

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