PayFlow

Freelancers lose $6K/year to unpaid invoices. PayFlow AI automatically sends escalating follow-up emails until you get paid. Set it once. Never chase a client again.

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PayFlow

Inspiration

Every freelancer has sent this email: "Hey, just following up on the invoice..." Then waited. Then sent it again. Then felt awful about it. Then let it go.

The average freelancer loses $6,000 a year to late-paying clients — not because clients refuse to pay, but because chasing payment is so uncomfortable that most freelancers give up. 71% report this as a chronic, recurring problem on every project.

We looked at every invoicing tool on the market — FreshBooks, Wave, HoneyBook — and realized they all solve the same problem: sending the invoice. Nobody owns what happens when the client doesn't pay. That silence between invoice sent and money received is where PayFlow was born.

What It Does

PayFlow is an AI-powered invoice escalation platform that automates the entire collections process for freelancers — from friendly reminder to legal demand — without the freelancer writing a single follow-up email.

Core features:

  • 5-stage AI escalation engine — automatically sends escalating emails (friendly reminder → firm nudge → formal notice → final warning → legal demand) triggered by days overdue, calibrated by AI to the client relationship tag (New / Repeat / VIP), sent directly from the freelancer's own Gmail
  • Universal invoice scanner — upload any PDF, JPG, or PNG invoice and Claude AI extracts all fields automatically
  • CSV batch import — import invoices from any existing tool in seconds
  • Complete financial dashboard — revenue tracking, recovery rate, top clients, monthly charts, invoice status breakdown
  • Client payment DNA — full financial history per client, reliability score, average days to pay
  • Tax summary export — monthly income breakdown ready for an accountant
  • Pricing tiers — Free ($0), Pro ($10/month), Shield+ ($30/month) with Stripe-connected checkout

How We Built It

Stack: Django + Django REST Framework (backend), React + TypeScript + Tailwind CSS (frontend), Claude AI via Vector LLM connector (AI email generation + invoice scanning), Google OAuth via Vector Auth, SMTP email delivery, SQLite with persistent storage.

Infrastructure: Built entirely on Vector AI — authentication, deployment, LLM connector, social signals monitoring, and email campaign tooling all provided by Vector out of the box.

AI integration: Every escalation email is generated by Claude with a prompt that includes client name, invoice amount, days overdue, relationship tag, and escalation stage. The tone calibrates automatically — a VIP client 7 days overdue gets a different email than a new client 30 days overdue.

GTM: Used Vector's Social Signals to monitor Reddit (r/freelance, r/webdev), LinkedIn, and X for freelancers actively posting about late payments. Identified 37 high-intent prospects in 4 hours. Sent a real escalation email to a real inbox during the hackathon as proof of end-to-end functionality.

Challenges We Ran Into

libSQL compatibility — Vector's database uses libSQL which does not support Django's django_datetime_extract function. Every date-based ORM query (__year, __month, TruncMonth) broke silently or threw 500 errors. We had to audit the entire codebase and replace all date extractions with Python-level datetime arithmetic using timedelta and date range filters.

Gmail OAuth scope — Getting real emails to land in client inboxes required the gmail.send scope on top of the standard OAuth flow. Wiring this through Vector's auth system while keeping credentials secure took several iterations.

Data persistence across restarts — Vector's sandbox environment reset the SQLite database on server restarts. We resolved this by anchoring the database path to BASE_DIR and running migrate --run-syncdb on every server start.

Scope creep — We started with a simple demand letter generator and ended up building a complete financial platform. Keeping the core wedge (escalation engine) as the lead feature while positioning everything else as supporting depth required deliberate restraint.

Accomplishments That We're Proud Of

  • End-to-end email delivery — a real AI-written escalation email was sent from a real Gmail account to a real client inbox during the hackathon. Not mocked. Not simulated. Live.
  • Universal invoice scanner — upload any invoice in any format and Claude reads it. This alone replaces hours of manual data entry.
  • 37 real leads identified in 4 hours using Vector's Social Signals — people actively posting about unpaid invoices on Reddit and LinkedIn right now.
  • Complete financial command center built in under 24 hours — revenue tracking, client profiles, recovery analytics, tax exports, and a 5-stage AI escalation engine all working end to end.
  • Zero to production in one day on a stack we hadn't used before.

What We Learned

  • The workflow wedge matters — starting with one specific, painful workflow (chasing late invoices) gave us a clear entry point and prevented us from building a platform before proving the core.
  • Distribution is as hard as building — finding 37 real prospects in 4 hours using intent signals was more valuable than any feature we built. The product can be perfect; it means nothing without someone to use it.
  • AI calibration over AI generation — the insight that made the escalation engine feel real was not just generating emails, but calibrating tone to relationship type and days overdue. Same technology, completely different result.
  • Vector removes the boilerplate — auth, payments, deployment, LLM connector, and GTM tooling all out of the box let us focus entirely on product logic instead of infrastructure plumbing.
  • Urgency is a business model — free tier converts to paid not through habit but through the exact moment when a client ignores Stage 2. Building a product where the upgrade trigger is the problem itself is a fundamentally different kind of growth.

What's Next for PayFlow

  • Stripe/FreshBooks/Wave sync — pull invoices directly from existing tools instead of CSV upload
  • Client reply interpreter — paste in what a client responded and AI classifies it (Promising / Disputing / Stalling / Ghosting) and drafts the perfect reply
  • Recovery probability score — AI predicts likelihood of payment per invoice based on days overdue, client history, and industry
  • Legal demand PDF — state-specific, professionally formatted demand letter downloadable at Stage 5
  • Small claims court form auto-fill — pre-populate the correct filing form for the freelancer's state
  • WhatsApp escalation — one-click escalation to WhatsApp when email isn't working at Stage 3+
  • Mobile app — freelancers are always on the go; PayFlow should work from the truck, the coffee shop, anywhere

Built With

  • githubapi
  • vector
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