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

> Find email addresses and send cold emails

- Site: https://hunter.io
- Category: B2B Sales & Outreach SaaS
- Platforms: Web app, Browser extension
- Verdict: **Serious undertaking** (38/100 vibecodeable)
- Estimated effort: 4-6 weeks of dedicated development

## Verdict

Build a personal lead-lookup and outreach dashboard subset, but keep paying for the real platform because you cannot replicate their 81M-website indexing database or pristine SMTP deliverability.

While you can easily spin up a Next.js dashboard with a SQLite database to mimic the UI, the core engine of Hunter relies on two violently difficult subsystems: low-level SMTP mailbox verification handshakes (which require maintaining clean IP reputation so you aren't flagged as a spammer) and indexing millions of web domains to harvest naming patterns. Vibecoding agents can build the CRUD wrappers and sequence scheduler in a weekend, but writing reliable email verification and scraping engines that scale requires deep networking and anti-bot engineering.

### What you can't replicate

- Proprietary B2B database indexing over 81 million websites
- Enterprise-grade email deliverability and IP reputation warmth
- 7 million active user trust and browser extension distribution network

## What it does

An all-in-one B2B email outreach and lead generation platform featuring domain search, email finding, verification, and automated sequences.

### Core features

- Domain search parsing public web records for name-to-email patterns
- Email verifier performing direct SMTP handshakes and mailbox checks
- B2B lead database with filtering and search
- Cold email sequence manager with scheduling and follow-ups
- Browser extension for capturing emails while browsing company websites
- Analytics tracking for open rates and campaign metrics
- Credit quota system governing searches and verifications

## The business

### Pricing

- Free: $0/mo
- Starter: $49/mo
- Growth: $149/mo
- Scale: $299/mo

Founded 2015.
Team size: 20-50.

## The hard parts

- Low-level SMTP validation without getting server IPs blacklisted as spam generators
- Scraping and indexing millions of corporate websites reliably to build a B2B directory
- Managing robust IMAP/SMTP connection rotation and warm-up for email outreach sequences
- Handling strict data privacy frameworks (GDPR/CCPA) regarding public personal business data

## How to vibe code Hunter

### Prerequisites

- Node.js (free): Required runtime for running Next.js and TypeScript backend logic
- GitHub (free): Code repository and deployment source control
- Resend (free tier available): Transactional email API for sending application alerts

### Recommended AI tools

- Claude Code: Best-in-class terminal coding agent for scaffolding multi-file Next.js apps, writing complex backend SMTP validation scripts, and debugging database queries.
- Cursor: Ideal for fine-tuning React UI components, Tailwind tables, and sequence builder interfaces with side-by-side diff reviews.

### Stack

- Frontend: Next.js with Tailwind CSS and shadcn/ui components
- Backend: Next.js Server Actions and Node.js background workers
- Database: Turso (SQLite at the edge for storing domains, leads, and sequences)
- Auth: better-auth
- Payments: Stripe
- Other: Resend for transactional emails, PostHog for product analytics

### Hosting

- Cloudflare (Hosting the Next.js frontend and edge API routes via Workers): $0-5/mo
- Railway (Running persistent background worker processes for email verification and sequence automation): ~$5/mo

### Build guide

1. **Scaffold Next.js App and Database Schema** — Initialize the Next.js project with Tailwind CSS, shadcn/ui, and configure Turso SQLite connection for users, domains, leads, and sequences.

```
Create a new Next.js 16 project with TypeScript, Tailwind CSS, and App Router. Set up Turso (libSQL) database client configuration with Drizzle ORM. Define database schemas for users, domains, contacts, email_verifications, and outreach_sequences with proper relational foreign keys, indexes, and timestamps. Implement better-auth for email/password authentication.
```

2. **Build Domain Search and Email Pattern Engine** — Implement the core search logic that accepts a company website, parses public DNS MX records, and applies common email naming patterns (e.g., {first}.{last}@domain.com).

```
Build a Domain Search feature in Next.js. Create a server action that takes a domain name, checks a local cache table, and if missing, performs a basic web fetch or uses an AI extraction tool to identify employee names and roles. Implement pattern matching algorithms to generate probable email permutations (e.g., first.last@domain, flast@domain) and save discovered contacts to the database.
```

3. **Implement Email Verifier with SMTP Handshake** — Develop a backend verification utility that checks syntax, queries MX records, and connects to target mail servers to verify mailbox existence.

```
Create an Email Verifier module using Node.js net/dns modules. The function must: 1. Validate email syntax with regex; 2. Query MX records for the domain; 3. Connect to the primary mail server via SMTP port 25; 4. Issue HELO, MAIL FROM, and RCPT TO commands to check if the mailbox responds with 250 OK without sending an actual email. Handle timeouts, greylisting gracefully, and return status codes (valid, invalid, risky, unknown) while updating the user's credit quota.
```

4. **Build Lead Discover and Search Interface** — Create a searchable dashboard view for exploring saved leads with filtering by department, location, and seniority.

```
Build a Discover leads dashboard page using shadcn/ui data tables and filters. Include multi-select filters for departments, countries, and seniorities. Connect the table to a backend API route that queries the contacts table with dynamic SQL WHERE clauses, pagination, and sorting. Add a 'Save to Leads' button that adds records to the user's personal list.
```

5. **Construct Cold Email Sequence Manager** — Build an outreach sequence creator supporting multi-step campaigns, delays, tracking, and recipient limits.

```
Build a Sequences feature in the Next.js app. Create database tables for sequences, sequence_steps (step number, delay days, email template subject/body), and sequence_recipients (tracking status: queued, sent, opened, replied). Build a visual builder UI allowing users to add steps and personalize templates using variables like {{first_name}} and {{company}}.
```

6. **Implement Background Sequence Dispatcher** — Set up a robust cron worker or background job runner to dispatch scheduled sequence emails respecting daily sending quotas.

```
Write a background worker script using Node.js and node-cron (to be deployed on Railway) that polls the sequence_recipients table every minute for due steps. The worker must fetch active sequence messages, personalize them with recipient data, dispatch them via configured SMTP/Resend integrations, log delivery status, and handle rate-limiting and daily send caps per account.
```

### Cost vs paying

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

- Domain name for self-hosted instance: $12/yr
- Total: ~$12 one-time

**Ongoing costs (monthly):**

- Cloudflare Workers / Railway hosting: ~$5/mo
- Total: ~$5/mo

- Paying for the SaaS instead: $49/mo (Starter plan)
- Build time: 45-60 hours
- AI tool credits: ~$20 (Claude Pro)
- Break-even: 1 month

## Sources

- [Hunter Official Website](https://hunter.io)
- [Hunter Pricing Page](https://hunter.io/pricing)
- [Hunter About Us Page](https://hunter.io/about)
- [Hunter Security Policy](https://hunter.io/security)