# How to Vibe Code Your Own ChartMogul (and Stop Paying for It)

> Subscription analytics and revenue growth platform for SaaS

- Site: https://chartmogul.com
- Category: Web app
- Verdict: **Serious undertaking** (35/100 vibecodeable)
- Estimated effort: 4-6 weeks of dedicated development

## Verdict

Build a subset with a single billing provider, but expect severe challenges handling out-of-order webhooks and precise MRR movement calculations.

Writing a personal clone that ingests Stripe webhooks and calculates simple MRR charts is straightforward, but replicating ChartMogul's robust data hygiene engine for out-of-order events, plan mid-cycle changes, and currency conversions requires a complex event-sourcing architecture that will consume weeks of debugging.

### What you can't replicate

- Integrations with 30+ proprietary billing APIs and their weird edge cases
- Global benchmark data sets
- SOC 2 compliance and institutional trust

## What it does

Aggregates, cleans, and analyzes billing data from multiple payment gateways to track critical SaaS metrics like MRR, ARR, churn, LTV, and NRR.

### Core features

- Multi-gateway webhook ingestion (Stripe, Chargebee, Paddle)
- Idempotent event-sourcing data pipeline
- MRR movement calculation (New, Expansion, Churn, Reactivation)
- Customer lifetime value & cohort analysis engines
- Data segmentation & filtering interface
- Subscription event-driven workflow automations

## The business

### Pricing

- Free: $0 / month
- Starter / Pro: $59 - $949+ / month
- Enterprise: $19,900+ / year

### Funding

$4M raised.
- Seed
Investors: European angel investors

Founded 2014.
Team size: 60-67.

## The hard parts

- Normalizing disparate billing schemas and webhook payloads into a unified subscription timeline
- Idempotent out-of-order event processing to prevent historical MRR corruption
- Optimized analytical aggregation queries for rolling cohort and retention windows
- Handling complex plan migrations, refunds, trials, and multi-currency FX conversions

## How to vibe code ChartMogul

### Prerequisites

- Node.js (free): Required runtime for Next.js full-stack development and TypeScript execution.
- GitHub (free): Source control and deployment pipeline integration.
- Stripe Account (free): Source of test subscription events and webhooks for ingestion testing.

### Recommended AI tools

- Claude Code: Best-in-class agentic coding tool for scaffolding complex multi-file data pipeline logic and database schemas.
- Cursor: Ideal for fine-tuning the analytics dashboard UI and complex charting components.

### Stack

- Frontend: Next.js with Tailwind CSS and Recharts
- Backend: Next.js API Routes / Server Actions
- Database: Neon (Serverless Postgres)
- Auth: better-auth
- Payments: Stripe (as data source only)
- Other: PostHog for product analytics, Sentry for error monitoring

### Hosting

- Vercel (Hosting the Next.js frontend and serverless API endpoints): $0/mo (Hobby tier)
- Neon (Serverless Postgres database for storing normalized subscription events and metrics): $0/mo (Free tier)

### Build guide

1. **Scaffold Database Schema and Authentication** — Initialize a Next.js project with Tailwind CSS, configure better-auth for single-user admin access, and set up Neon Postgres tables for organizations, customers, subscriptions, invoices, and raw webhook events.

```
Create a new Next.js 16 project with TypeScript and Tailwind CSS v4. Set up better-auth connected to a Neon Postgres database using Drizzle ORM. Define database schemas for tenants, customers, subscriptions (with status, plan_id, current_period_start, current_period_end), invoices (amount_paid, currency, status, created_at), and raw_webhook_events (id, provider, payload, processed_at, error). Ensure proper indexing on customer_id and subscription_id foreign keys.
```

2. **Stripe Webhook Ingestion Engine** — Build an idempotent webhook ingestion endpoint that receives Stripe events (customer.subscription.created, updated, deleted, invoice.payment_succeeded), stores raw payloads, and handles duplicate deliveries safely.

```
Implement a secure API route at `/api/webhooks/stripe` that verifies Stripe webhook signatures. Store every incoming event in the `raw_webhook_events` table with idempotency checks based on Stripe's event ID. Parse the event payload and upsert corresponding records into customers, subscriptions, and invoices tables without throwing unhandled exceptions if events arrive out of order.
```

3. **MRR Calculation & Event Sourcing Pipeline** — Develop background worker logic or utility functions to compute Monthly Recurring Revenue (MRR) movements—New, Expansion, Contraction, and Churn—on a daily or monthly calendar basis.

```
Create a calculation engine function in TypeScript that processes subscription state transitions from the database. Implement logic to calculate monthly recurring revenue (MRR) per customer, classifying changes between consecutive months into New MRR, Expansion MRR, Contraction MRR, Churned MRR, and Reactivation MRR. Store computed historical snapshots in a daily_metrics table.
```

4. **Core Metrics Dashboard UI** — Build the main analytics dashboard displaying high-level SaaS KPI cards (MRR, ARR, ARPU, Churn Rate, LTV) and time-series charts using Recharts.

```
Build a dashboard page in Next.js using Tailwind CSS and Recharts. Create KPI summary cards for MRR, ARR, Churn Rate, and ARPU based on data queried from the daily_metrics table. Add interactive area charts showing MRR growth broken down by movement components (New, Expansion, Contraction, Churn) over the last 12 months.
```

5. **Customer Segmentation and Detail View** — Implement a customer table view with search, filtering by plan or status, and a detailed customer drawer showing timeline history and LTV metrics.

```
Create a customers list page with search filtering by email and status (active, trialing, canceled). Clicking a customer opens a detail view displaying their full subscription timeline, total revenue generated, active plans, and invoice history. Ensure all queries are optimized with proper database indexes.
```

### Cost vs paying

**Starting costs (one-time):**

- AI Coding Assistant (Claude Pro): $20.00
- Total: $20.00 one-time

**Ongoing costs (monthly):**

- Vercel Hobby & Neon Free Tier: $0.00/mo
- Total: $0.00/mo

- Paying for the SaaS instead: $59/mo - $949+/mo
- Build time: 40-60 hours
- AI tool credits: $20 (Claude Pro)
- Break-even: Immediate

## Sources

- [ChartMogul Official Website](https://chartmogul.com)
- [ChartMogul Pricing Page](https://chartmogul.com/pricing)
- [Himalayas - ChartMogul Tech Stack Profile](https://himalayas.app/companies/chartmogul/tech-stack)