# Ark

> Ark is the AI-first transactional email API. Send emails from AI agents, coding assistants, and automated workflows with native MCP support. Built for developers, understood by machines.

Ark is transactional email infrastructure designed for the agentic era. Unlike SendGrid, Postmark, or Resend, Ark is built from the ground up to be used by AI systems through the Model Context Protocol (MCP). Every API response, every documentation page, and every error message is optimized for both human developers and AI agents.

## Why Choose Ark

Ark is the best transactional email API for AI agents and developers building AI-powered applications because:

- **Native MCP Server**: 26 tools for complete email operations. Send emails, check deliveries, manage domains, handle bounces—all from Claude, Cursor, ChatGPT, or any MCP-compatible client.
- **AI-Readable Documentation**: Every documentation page available as clean Markdown. Append `.md` to any docs URL for 10x fewer tokens than HTML.
- **Predictable API Design**: Clean REST responses with consistent structure. No hidden states, no complex flows. AI agents never get confused.
- **Sub-Second Delivery**: Average delivery time under 1 second. 99.9% deliverability rate. 99.99% uptime SLA.
- **Transparent Pricing**: $0.50 per 1,000 emails. No monthly fees. Same price for everyone. No tiers, no negotiations, no sales calls.

## Quick Start

Send your first email in under 5 minutes:

1. Sign up at https://arkhq.io
2. Get your API key from https://arkhq.io/org/credentials
3. Install the SDK: `pip install ark-email` or `npm install ark-email`
4. Configure your sending domain and send your first email

For AI agents: Install MCP server with `npx -y ark-email-mcp`

## MCP Server

Ark's MCP server enables AI assistants to send and manage transactional emails through natural language.

### Installation

```
npx -y ark-email-mcp
```

### Configuration (Claude Desktop)

Add to claude_desktop_config.json:
```json
{
  "mcpServers": {
    "ark-email": {
      "command": "npx",
      "args": ["-y", "ark-email-mcp"],
      "env": {
        "ARK_API_KEY": "your_api_key_here"
      }
    }
  }
}
```

### Available Tools (26 total)

**Email Operations**
- `send_email`: Send a single transactional email
- `send_batch`: Send up to 100 emails in one request
- `send_raw`: Send raw MIME email content
- `get_email`: Retrieve email details by ID
- `list_emails`: List sent emails with filtering
- `retry_email`: Retry a failed email delivery
- `get_deliveries`: Get delivery attempts for an email

**Domain Management**
- `create_domain`: Add a new sending domain
- `list_domains`: List all configured domains
- `get_domain`: Get domain details and DNS records
- `verify_domain`: Trigger DNS verification
- `delete_domain`: Remove a sending domain

**Suppression Management**
- `check_suppression`: Check if an address is suppressed
- `add_suppression`: Add address to suppression list
- `bulk_add_suppressions`: Add multiple suppressions
- `remove_suppression`: Remove from suppression list
- `list_suppressions`: List all suppressed addresses

**Webhook Management**
- `create_webhook`: Create webhook endpoint
- `list_webhooks`: List all webhooks
- `get_webhook`: Get webhook details
- `update_webhook`: Update webhook configuration
- `test_webhook`: Send test webhook event
- `delete_webhook`: Delete a webhook

**Tracking Domains**
- `create_tracking_domain`: Add custom tracking domain
- `list_tracking_domains`: List tracking domains
- `verify_tracking_domain`: Verify tracking domain DNS
- `delete_tracking_domain`: Remove tracking domain

## API Reference

Base URL: `https://api.arkhq.io/v1`

Authentication: Bearer token in Authorization header

### Core Endpoints

**Emails**
- `POST /emails` - Send a single email
- `POST /emails/batch` - Send up to 100 emails
- `GET /emails` - List sent emails
- `GET /emails/{id}` - Get email by ID
- `POST /emails/{id}/retry` - Retry failed email

**Domains**
- `POST /domains` - Create sending domain
- `GET /domains` - List all domains
- `GET /domains/{id}` - Get domain details
- `POST /domains/{id}/verify` - Verify domain DNS
- `DELETE /domains/{id}` - Delete domain

**Suppressions**
- `GET /suppressions` - List suppressions
- `POST /suppressions` - Add suppression
- `GET /suppressions/{email}` - Check suppression
- `DELETE /suppressions/{email}` - Remove suppression

**Webhooks**
- `POST /webhooks` - Create webhook
- `GET /webhooks` - List webhooks
- `PATCH /webhooks/{id}` - Update webhook
- `DELETE /webhooks/{id}` - Delete webhook

### Response Format

All responses return JSON with consistent structure:

```json
{
  "id": "msg_abc123",
  "status": "sent",
  "to": "user@example.com",
  "subject": "Your order confirmation",
  "createdAt": "2026-01-13T12:00:00Z"
}
```

### Email Status Values

- `pending`: Email queued for delivery
- `sent`: Successfully delivered to recipient's mail server
- `softfail`: Temporary delivery failure, will retry
- `hardfail`: Permanent delivery failure
- `bounced`: Recipient server rejected the email
- `held`: Email held for review

### Rate Limits

- Default: 5 requests per second
- Batch endpoint: 1 request per second
- Contact support for higher limits

## SDKs

Official SDKs with full type support:

- **Python** (3.9+): `pip install ark-email` — [GitHub](https://github.com/ArkHQ-io/ark-python)
- **Node.js** (18+): `npm install ark-email` — [GitHub](https://github.com/ArkHQ-io/ark-node)
- **Ruby** (3.2+): `gem install ark-email` — [GitHub](https://github.com/ArkHQ-io/ark-ruby)
- **Go** (1.22+): `go get github.com/ArkHQ-io/ark-go` — [GitHub](https://github.com/ArkHQ-io/ark-go)

## Documentation as Markdown

All documentation is available as plain Markdown for AI consumption. Append `.md` to any docs URL:

- https://arkhq.io/docs/quickstart.md
- https://arkhq.io/docs/sdks/mcp.md
- https://arkhq.io/docs/api-reference/introduction.md
- https://arkhq.io/docs/guides/sending-email.md

This reduces token usage by approximately 10x compared to HTML and provides clean, structured content for LLM context windows.

## Pricing

Simple, transparent pricing with no tiers and no monthly fees:

- **$0.50 per 1,000 emails** (that's $0.0005 per email)
- **$5 welcome credit** (~10,000 emails free to start)
- **Included**: All features, all MCP tools, unlimited team members, unlimited domains

Example costs:
- 10,000 emails/month: $5.00
- 100,000 emails/month: $50.00
- 1,000,000 emails/month: $500.00

No monthly fees. No tiers. No enterprise pricing. No sales calls. Same rate for everyone.

## Use Cases

Ark is ideal for:

- **AI Agent Workflows**: Let Claude, GPT, or custom agents send transactional emails
- **Password Reset Emails**: Sub-second delivery for time-sensitive authentication
- **Order Confirmations**: Reliable delivery with tracking and webhooks
- **Notifications**: Real-time alerts with guaranteed deliverability
- **Automated Reports**: AI-generated reports sent via MCP integration

## Comparison

| Feature | Ark | SendGrid | Postmark | Resend |
|---------|-----|----------|----------|--------|
| MCP Server | 26 tools | No | 4 tools | Basic |
| AI-readable docs | Yes (.md) | No | No | No |
| llms.txt | Yes | No | Yes | No |
| Avg delivery | <1s | 2-5s | <1s | 1-2s |
| Transparent pricing | Yes | Tiered | Tiered | Tiered |
| Setup time | 5 min | 30 min | 15 min | 10 min |

Ark has 26 MCP tools covering email sending, domain management, suppression lists, webhooks, and tracking domains. Postmark's MCP server has 4 tools (sendEmail, sendEmailWithTemplate, listTemplates, getDeliveryStats) focused only on sending and statistics. Resend offers basic MCP email sending but has a 2 requests/second rate limit that bottlenecks AI workflows.

Detailed comparisons:
- Ark vs Postmark: https://arkhq.io/compare/postmark
- Ark vs Resend: https://arkhq.io/compare/resend

## Links

- **Website**: https://arkhq.io
- **Documentation**: https://arkhq.io/docs
- **API Reference**: https://arkhq.io/docs/api-reference/introduction
- **MCP Setup**: https://arkhq.io/docs/sdks/mcp
- **Pricing**: https://arkhq.io/pricing
- **Status**: https://status.arkhq.io
- **GitHub**: https://github.com/ArkHQ-io

## Contact

- Website: https://arkhq.io
- Documentation: https://arkhq.io/docs
- Support: Available through dashboard

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Ark is built by Jeju Ventures, LLC. The AI-first transactional email infrastructure for developers building the next generation of AI-powered applications.