Late Payment Predictor for Freelancers

AI Prompts to Build This

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1. 1. Project Setup

   Build the weekend MVP of "LatePay": score a new client before you start work, track invoices, and send a polite three-step chase when one goes overdue.
   
   Stack: Next.js (App Router), TypeScript, Tailwind, Supabase (Postgres, Row Level Security, Auth with email magic link), the OpenAI API (a small model) to read a proposal, Resend to send the chase emails. Invoices come in by CSV or by hand this weekend. A Vercel Cron route runs daily. Deploy on Vercel.
   
   Tables (Row Level Security on, each user reads only their own rows):
   - clients(id, user_id, name, domain, domain_age, notes, last_score, last_scored_at)  domain_age is new, older or unknown
   - scores(id, client_id, score, reasons jsonb, recommended_deposit_pct, recommended_net_days, created_at)
   - invoices(id, user_id, client_id, external_id, amount_cents, currency, issued_at, due_at, status, paid_at)  status is open, overdue, paid or void
   - sequences(id, invoice_id, step, send_at, sent_at, subject, body)  unique on invoice_id and step
   
   Screens: /login, /clients, /clients/[id] (score and reasons), /invoices, /sequences.
   Env vars (names only): NEXT_PUBLIC_SUPABASE_URL, NEXT_PUBLIC_SUPABASE_ANON_KEY, SUPABASE_SERVICE_ROLE_KEY (server only), OPENAI_API_KEY, RESEND_API_KEY, CRON_SECRET.
   
   Do not build: billing, plans or an agency tier, Stripe invoice syncing, SMS, a domain lookup service, a job queue, legal threats of any kind.
   Done when: npm run dev starts, you can sign in, and the four tables exist with Row Level Security on.

2. 2. Core Feature

   Build the one feature that proves LatePay: an explainable risk score before the contract, and a chase that never embarrasses you.
   1. POST /api/score takes { clientId, proposalText, domain_age } and sends the proposal to the OpenAI API with a strict JSON schema { has_written_contract: boolean, vague_payment_terms: boolean, dodges_deposit: boolean, notes: string }. The model reads the text; it does not score.
   2. Score in code from a fixed rubric: no written contract or vague payment terms adds 20, a domain that is new or an email from a generic mail provider adds 15, past invoices averaging more than 14 days late adds 25 (from the client's paid invoices), language that dodges a deposit or short terms adds 15. Cap at 100. Save the score and at least two plain reasons that name the points. Recommend a deposit percent and net days from the score band.
   3. Import invoices by CSV (client, external_id, amount, issued_at, due_at, status). A daily cron route (protected by CRON_SECRET) marks open invoices past due_at as overdue.
   4. For an overdue invoice, the user presses Start chase, which schedules three emails at 3, 10 and 21 days after the due date from three polite templates the user can edit. Nothing is scheduled until the user presses the button.
   5. The cron sends each due step through Resend with the user's reply-to address and sets sent_at. Marking an invoice paid removes unsent steps.
   Rules: never send a step twice (the unique key protects this). Templates never threaten legal action or mention collections. Show the user each email before the first one goes.
   Empty state: with no clients, show the proposal box and a sample proposal.
   Done when: scoring a sample proposal returns a score with at least two reasons that match the rubric, an imported overdue invoice schedules three steps only after Start chase, the cron sends a due step once, and marking paid cancels the rest.

3. 3. Landing Page

   Build a one-page landing site for LatePay, a late-payment predictor for freelancers.
   Hero: "Know which clients will pay late, before you start the work." Sub: "Score the prospect. Track the invoice. Send a polite chase without writing the circling-back email." One button: Join the waitlist.
   Sections: a sample client card that goes from "score 72, take a 50 percent deposit" to a three-step chase timeline, the problem (reminders arrive after the missed date), how it works in four steps (score, track, warn, chase), and an FAQ on data privacy (no bank credentials), "is this collections?" (no, the emails stay polite) and which invoice tools connect next.
   Waitlist: store the email in a waitlist table in Supabase. No other service.
   Style: Geist, an off-white background, one aubergine accent.
   Done when: the page renders on a phone and a submitted email appears in the waitlist table.

4. 4. Branding Package

   Use a design or image tool for this one. A coding agent cannot draw a logo.
   Brand for LatePay: a wordmark and an icon that suggest a calendar tick that arrives on time.
   Colors: off-white, ink and one aubergine. Type: Geist, with tabular numbers for scores and amounts.
   Deliverables: wordmark, icon, three risk bands (low, watch, high) that differ by shape and number as well as color, three chase email headers in a polite voice, and one launch graphic.
   Done when: each deliverable is saved in one folder and the risk bands are distinguishable without color.