Fintech

Bond Generator

Municipal Bond Certificate Generation Workflow

A tool that generates municipal bond certificates from uploaded DOCX templates, maturity schedules, and CUSIP data. Turns manual certificate assembly into a structured, auditable workflow, with Stripe subscription billing architecture available behind feature flags.

Portfolio Case Study

This entry uses sanitized screenshots, feature breakdowns, and architecture notes. These products are not publicly accessible.

The Challenge

Bond certificate generation requires merging complex financial data — maturity schedules, CUSIP numbers, interest rates, legal party names — into legal DOCX templates. One error invalidates the entire certificate series. Teams were doing this manually in Word, one certificate at a time.

What We Built

→DOCX template upload with tag-based field detection
→Maturity schedule parser handling Excel and CSV formats via the xlsx library
→CUSIP data parsing with field validation
→Editable data preview table before certificate generation
→Certificate assembly engine merging verified data into the template
→Draft save system for in-progress certificate jobs
→Stripe subscription billing architecture with trial period and webhook-confirmed access control (feature-flagged)
→Trial expiration email notifications (feature-flagged)

What Makes It Different

✦Tag-based DOCX template system — any template can be onboarded without code changes to the generation engine
✦Maturity schedule parser handles format variations from different bond counsel offices
✦Stripe webhook access gates — designed so subscription lapses can cut off certificate generation
✦Draft system preserves parsed data across sessions without re-uploading the schedule

Architecture Highlights

·Webhook-first Stripe integration — access control decisions are made server-side from verified webhook events when billing is enabled
·Template tag registry decouples template onboarding from the core generation engine
·Streaming generation response allows the UI to show progress on large bond series
·Supabase storage with per-user bucket policies for template and output isolation

Results

Launchable certificate-generation workflow with deterministic DOCX assembly, draft persistence, CI checks, and subscription billing architecture. Billing and trial surfaces are feature-flagged and not claimed as actively monetized here.

Tech Stack

Next.js 15SupabaseStripexlsxDOCXMUIZodSentry

Relevant For

Fintech and financial document tools
SaaS with Stripe billing and subscriptions
Document generation and assembly systems
Legal and compliance software
Data-to-document workflows

Tech Stack — How Each Piece Is Used

Next.js 15App Router with file upload API routes and streaming certificate generation responses

SupabaseAuth, DOCX template storage, draft persistence, and subscription state tracking

StripeSubscription management, trial periods, and webhook-driven access control — gated by environment feature flags

xlsxParses maturity schedule spreadsheets from any bond counsel into structured maturity records

DOCX toolingTag-based template detection and data-merged certificate output generation

MUIData grid UI for reviewing and editing parsed maturity and CUSIP records before generation

ZodStrict schema validation for maturity schedule formats and CUSIP input structures

SentryError tracking with certificate job context for debugging generation failures

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