Product Requirements Document: CashFlow Chaser Pro

1. Executive Summary

CashFlow Chaser Pro is a specialized accounts receivable automation platform designed for freelancers, digital agencies, and SMBs. By integrating directly with accounting software (QuickBooks/Xero) and payment gateways (Stripe/Plaid), the platform eliminates the manual effort of "chasing" late payments. It provides automated, multi-channel reminder sequences, a secure white-labeled payment portal, and AI-driven cash flow forecasting to ensure businesses maintain a healthy liquidity position.

2. Problem Statement

Small businesses and freelancers lose an average of 20 days per year manually following up on unpaid invoices. Manual tracking leads to "leaky" cash flow, where late payments (often 30+ days overdue) force owners to dip into personal savings or high-interest credit lines to cover operational costs. Existing accounting tools provide invoicing but lack the aggressive, automated "chasing" logic required to change client payment behavior.

3. Goals & Success Metrics

• Reduce Days Sales Outstanding (DSO): Target a 25% reduction in average payment time for users within the first 90 days.
• Automation Efficiency: 90% of follow-ups should be handled without manual intervention.
• Recovery Rate: Increase the percentage of "90-day+ overdue" invoices successfully collected.
• User Retention: High stickiness through deep integration with the user's primary financial stack (QuickBooks/Stripe).

4. User Personas

A. Sarah, the Freelance Designer

• Need: Wants to look professional but hates asking for money.
• Pain: Clients often "forget" her Net-15 terms.
• Goal: Set-and-forget automation that handles reminders politely but firmly.

B. Mark, the Agency Owner

• Need: High-volume invoice tracking across 50+ active clients.
• Pain: Needs to see which clients are "at risk" to prioritize account management calls.
• Goal: A centralized aging dashboard and white-labeled portal that matches his agency branding.

C. David, the Operations Manager (SMB)

• Need: Reconciliation between the bank and the ledger.
• Pain: Partial payments and ACH failures cause manual data entry nightmares.
• Goal: Secure ACH integration and automated "closed-loop" reconciliation.

5. User Stories

• As a user, I want to connect my QuickBooks account so that my invoices are automatically imported and synced in real-time.
• As a user, I want to define a sequence (e.g., Email at T-3 days, SMS at T+1 day) so that I don't have to manually check my calendar to follow up.
• As a client (payer), I want to click a single link in an email to pay via ACH or Credit Card without creating an account.
• As a user, I want to see an aging report (30/60/90 days) so that I can visualize my total outstanding revenue at a glance.

6. Functional Requirements

6.1 Integration & Sync

• Bi-directional sync with QuickBooks Online and Xero.
• Real-time webhook listeners for invoice status changes (Paid, Voided, Partially Paid).
• Automatic reconciliation: marking an invoice as "Paid" in the accounting software once Stripe confirms settlement.

6.2 Automation Engine

• Customizable "Chaser" templates with dynamic placeholders (e.g., {{invoice_amount}}, {{due_date}}).
• Multi-channel support: Email (Postmark/SendGrid) and SMS (Twilio).
• Escalation logic: Ability to change the tone of messages as the invoice ages.

6.3 White-Label Client Portal

• Unique, tokenized URLs for every invoice.
• Dynamic branding: Logo and primary color injection based on the sender's settings.
• Embedded payment options: Stripe Credit Card and Plaid-powered ACH.

6.4 Reporting & Analytics

• Visual Aging Dashboard using stacked bar charts.
• AI Probability Scoring: Predicting the likelihood of payment based on historical client behavior.

7. Technical Requirements

7.1 Tech Stack (2026 Standards)

• Frontend: React 19.2.x (utilizing React Compiler and Server Actions), TypeScript 6.0, Tailwind CSS 4.1.x (Oxide engine).
• Backend: NestJS 11.1.x (running on Node.js 24 LTS, using Express 5).
• Database: PostgreSQL with Row-Level Security (RLS) for strict tenant isolation.
• Task Queue: BullMQ (Redis-backed) for managing delayed reminder sequences and rate-limited API syncs.
• Identity: Clerk (Multi-tenant Organization management).

7.2 Core Integrations

• Payments: Stripe API (Payment Intents, Connect).
• Banking: Plaid API (for ACH auth).
• Accounting: Intuit (QuickBooks) and Xero OAuth2 flows.
• Communication: Twilio (SMS), Postmark (Transactional Email).

8. Data Model

| Entity | Attributes | Relationships | | :--- | :--- | :--- | | Organization | id, name, stripe_account_id, brand_settings (JSON) | 1:N Clients, 1:N Sequences | | Client | id, org_id, external_id, email, phone, avg_payment_days | N:1 Organization, 1:N Invoices | | Invoice | id, client_id, amount, status, due_date, tokenized_url | N:1 Client, 1:N Reminders | | Reminder | id, invoice_id, type (Email/SMS), scheduled_at, sent_at | N:1 Invoice |

9. API Specification (Sample Endpoints)

GET /api/v1/invoices/aging

• Description: Returns invoice totals grouped by 30/60/90 day buckets.
• Response:

  {
    "buckets": {
      "current": 4500.00,
      "30_days": 1200.50,
      "60_days": 800.00,
      "90_days": 250.00
    },
    "at_risk_count": 3
  }
  

POST /api/v1/portal/session

• Description: Validates a tokenized link and returns branding + invoice data for the public portal.
• Request: { "token": "abc-123-signed-hmac" }

10. UI/UX Requirements

• Dashboard: Must feature an ApexCharts-based stacked bar chart for aging.
• Onboarding Wizard: 3-step process: (1) Connect Accounting, (2) Link Stripe, (3) Choose Reminder Template.
• Mobile-First Portal: The client payment portal must be optimized for one-handed payment via mobile wallets (Apple/Google Pay).

11. Non-Functional Requirements

• Security: AES-256 encryption for OAuth tokens; PCI-DSS 4.0 compliance (no raw card data stored).
• Performance: Dashboard load time < 1.5s; Webhook processing < 2s to comply with Intuit's timeout.
• Scalability: BullMQ workers must scale horizontally to handle Monday morning "reminder spikes."

12. Out of Scope

• Full-scale accounting/bookkeeping features (we are a layer on top, not a replacement).
• Physical mail/letter reminders.
• Legal debt collection services (referral only).

13. Risks & Mitigations

• Risk: QuickBooks/Xero API Rate Limiting.
  • Mitigation: Implement BullMQ with per-tenant rate limiters and Exponential Backoff.
• Risk: Data Leakage between tenants.
  • Mitigation: Enforce PostgreSQL Row-Level Security (RLS) and AS RESTRICTIVE policies.

14. Implementation Tasks

Phase 1: Project Setup & Foundation

• [ ] Initialize NestJS 11.1.x backend with TypeScript 6.0
• [ ] Initialize React 19.2.x frontend with Tailwind CSS 4.1.x (Oxide engine)
• [ ] Set up PostgreSQL with RLS schema for multi-tenancy
• [ ] Configure Clerk for Organization-based identity management
• [ ] Set up BullMQ with Redis for background job processing

Phase 2: Accounting & Payment Integrations

• [ ] Implement OAuth2 flow for QuickBooks Online
• [ ] Implement OAuth2 flow for Xero
• [ ] Create background worker for initial invoice ingestion (full sync)
• [ ] Integrate Stripe Connect for user onboarding
• [ ] Integrate Plaid Link for ACH bank verification

Phase 3: Automation Engine

• [ ] Build Template Editor with placeholder support
• [ ] Implement "Reminder Sequence" logic (T-minus/T-plus triggers)
• [ ] Set up Twilio and Postmark service providers
• [ ] Create idempotency checks to prevent duplicate reminders

Phase 4: Client Portal & Dashboard

• [ ] Build white-label portal using CSS Variables for dynamic branding
• [ ] Implement "Pay Now" flow using Stripe Payment Element
• [ ] Build Aging Dashboard with ApexCharts (30/60/90 buckets)
• [ ] Implement "Payment Received" webhook for real-time dashboard updates

Phase 5: Testing & Deployment

• [ ] Run PCI-DSS 4.0 compliance audit on payment flows
• [ ] Load test BullMQ workers for 10k concurrent messages
• [ ] Deploy to AWS ECS (Backend) and Vercel (Frontend)
• [ ] Set up automated backup and failover for PostgreSQL RDS