Building a Better Way to Track Domain Prices: My Journey Creating TLDSpy API

Arnaud DE SAINT JEAN — Sun, 16 Feb 2025 14:18:00 +0000

Hey everyone,

I wanted to share a side project I've been working on, something born out of my own frustration and, hopefully, something that might be useful to others here in the dev community.

The Backstory: A Domain Portfolio Manager Needs Accurate Data

I'm building a domain portfolio manager (it's still a work in progress!). As part of that project, I needed a reliable source of domain pricing data, specifically for comparing prices across different registrars. I was surprised at how difficult it was to find something that met my needs. Scraping was a nightmare (constantly breaking!), existing APIs were either incomplete, provided wrong data, or didn't offer the specific endpoints I was looking for.

So, like any indie hacker, I decided to build my own. That's how TLDSpy API came to life. I've now decided to make this stand-alone and provide this as a service.

TLDSpy API: What It Does

TLDSpy API is designed to provide accurate and comprehensive domain pricing and information. Here's a quick overview of what it offers:

Price Comparison: Compare registration, renewal, and transfer prices across multiple registrars.
Domain Info: Access WHOIS, DNS, SSL, and domain status data.
Price History Tracking: Since February 2025 for historical insights.

A Little Technical Dive: Getting Started

The API is pretty straightforward to use. Here's an example of how you can find the cheapest registrars for a .com domain using curl:

curl -X GET "https://api.tldspy.com/api/v1/prices/cheapest?tlds=com&limit=3"
-H "X-API-Key: YOUR_API_KEY"

This returns a JSON response like this:

{
  "results": {
    "com": {
      "registrar_count": 42,
      "avg_prices": {
        "register": 12.99,
        "renew": 14.99,
        "transfer": 12.99
      },
      "cheapest_register": [
        {
          "rank": 1,
          "registrar_name": "Cloudflare",
          "register_price": 8.57,
          "renew_price": 8.57,
          "transfer_price": 8.57,
          "total_cost_1_year": 8.57,
          "total_cost_3_year": 25.71,
          "total_cost_5_year": 42.85
        },
        {
          "rank": 2,
          "registrar_name": "Porkbun",
          "register_price": 8.88,
          "renew_price": 9.48,
          "transfer_price": 8.88,
          "total_cost_1_year": 8.88,
          "total_cost_3_year": 27.84,
          "total_cost_5_year": 46.80
        }
      ]
    }
  }
}

Here's another example to compare registrar prices for multiple TLDs:

curl -X GET "https://api.tldspy.com/api/v1/prices?tlds=com,net,org&registrars=namecheap,cloudflare" \
  -H "X-API-Key: YOUR_API_KEY"

This call would give you a JSON response like this:

{
  "results": {
    "com": {
      "namecheap": {
        "register_price": 9.99,
        "renew_price": 12.99,
        "transfer_price": 9.99,
        "last_updated": "2024-01-15T10:30:00Z"
      },
      "cloudflare": {
        "register_price": 8.57,
        "renew_price": 8.57,
        "transfer_price": 8.57,
        "last_updated": "2024-01-16T12:00:00Z"
      }
    },
    "net": {
      "namecheap": {
        "register_price": 11.99,
        "renew_price": 14.99,
        "transfer_price": 11.99,
        "last_updated": "2024-01-15T10:30:00Z"
      },
      "cloudflare": null
    },
    "org": {
      "namecheap": {
        "register_price": 10.99,
        "renew_price": 13.99,
        "transfer_price": 10.99,
        "last_updated": "2024-01-15T10:30:00Z"
      },
      "cloudflare": null
    }
  },
  "stats": {
    "total_tlds": 3,
    "time_elapsed": "2.186208ms",
    "last_updated": "2024-01-16T12:00:00Z"
  },
  "unsupported_registrars": [],
  "meta": {
    "restricted_tlds": [],
    "upgrade_message": null
  }
}

For those needing to perform bulk lookups, the API offers a batch domain lookup endpoint. Here's an example of how to check WHOIS and SSL information for multiple domains:

curl -X POST "https://api.tldspy.com/api/v1/domains" \
  -H "Content-Type: application/json" \
  -H "X-API-Key: YOUR_API_KEY" \
  -d '{
    "domains": ["example.com", "example.net"],
    "options": {
      "whois": true,
      "ssl": true
    }
  }'

{
  "results": {
    "example.com": {
      "domain": "example.com",
      "whois": {
        "domain": "example.com",
        "registrar": "Namecheap, Inc.",
        "registrar_key": "namecheap",
        "registrar_iana_id": "1068",
        "registrar_url": "https://www.namecheap.com",
        "creation_date": "1995-03-16T05:00:00Z",
        "expiry_date": "2025-03-17T05:00:00Z",
        "last_updated": "2024-02-28T14:48:12Z",
        "status": [
          "clientTransferProhibited"
        ],
        "nameservers": [
          "ns1.example.com",
          "ns2.example.com"
        ],
        "source_library": "whois-go",
        "is_available": false
      },
      "dns": {
        "a_records": [
          "93.184.216.34"
        ],
        "aaaa_records": [
          "2606:2800:220:1:248:1893:25c8:1946"
        ],
        "mx_records": [
          "10 mail.example.com"
        ],
        "txt_records": [
          "v=spf1 -all"
        ],
        "ns_records": [
          "ns1.example.com",
          "ns2.example.com"
        ],
        "cname_records": [
          "www.example.com"
        ],
        "dnssec": {
          "enabled": true,
          "ds_records": [
            "12345 13 2 ABCDEF123456789..."
          ]
        }
      },
      "ssl": {
        "valid": true,
        "issuer": "DigiCert Inc",
        "subject": "example.com",
        "version": "3",
        "serial_number": "0123456789ABCDEF",
        "not_before": "2024-01-01T00:00:00Z",
        "not_after": "2025-01-01T23:59:59Z",
        "san_list": [
          "example.com",
          "www.example.com"
        ]
      },
      "status": {
        "available": true,
        "status_code": 200,
        "response_time_ms": 245,
        "protocol": "https",
        "checked_at": "2024-01-15T10:30:00Z",
        "error": null
      },
      "available": false,
      "errors": null
    },
    "example.net": {
      "domain": "example.net",
      "whois": {
        "domain": "example.net",
        "registrar": "Namecheap, Inc.",
        "registrar_key": "namecheap",
        "registrar_iana_id": "1068",
        "registrar_url": "https://www.namecheap.com",
        "creation_date": "1997-01-29T05:00:00Z",
        "expiry_date": "2025-01-30T05:00:00Z",
        "last_updated": "2024-02-28T14:48:12Z",
        "status": [
          "clientTransferProhibited"
        ],
        "nameservers": [
          "ns1.example.net",
          "ns2.example.net"
        ],
        "source_library": "whois-go",
        "is_available": false
      },
      "dns": {
        "a_records": [
          "93.184.216.34"
        ],
        "aaaa_records": [
          "2606:2800:220:1:248:1893:25c8:1946"
        ],
        "mx_records": [
          "10 mail.example.net"
        ],
        "txt_records": [
          "v=spf1 -all"
        ],
        "ns_records": [
          "ns1.example.net",
          "ns2.example.net"
        ],
        "cname_records": [
          "www.example.net"
        ],
        "dnssec": {
          "enabled": true,
          "ds_records": [
            "12345 13 2 ABCDEF123456789..."
          ]
        }
      },
      "ssl": {
        "valid": true,
        "issuer": "DigiCert Inc",
        "subject": "example.net",
        "version": "3",
        "serial_number": "0123456789ABCDEF",
        "not_before": "2024-01-01T00:00:00Z",
        "not_after": "2025-01-01T23:59:59Z",
        "san_list": [
          "example.net",
          "www.example.net"
        ]
      },
      "status": {
        "available": true,
        "status_code": 200,
        "response_time_ms": 245,
        "protocol": "https",
        "checked_at": "2024-01-15T10:30:00Z",
        "error": null
      },
      "available": false,
      "errors": null
    }
  },
  "stats": {
    "total_domains": 2,
    "successful": 2,
    "failed": 0,
    "time_elapsed": "1.234s"
  }
}

More examples

You can find more detailed documentation, including endpoints for WHOIS, DNS lookups, and more examples in multiple languages (Python, JavaScript, Go, Ruby) here: https://api.tldspy.com/docs

Why I'm Sharing (and Asking for Feedback)

I've reached a point where I think TLDSpy API could be valuable to others, especially those working on domain-related projects, tools, or even just trying to make informed decisions about domain registration.

I'd love to get your feedback on this:

Is this something you'd find useful in your projects?
Are there any features or endpoints you'd like to see added?
Any thoughts on the pricing structure?

I'm currently offering a free tier with access to several popular TLDs. You can get started here: https://tldspy.com No credit card required.

I'm really eager to hear your thoughts and suggestions. Thanks for taking the time to read about my project!

Happy coding,

Arnaud

DEV Community: Arnaud DE SAINT JEAN

Building a Better Way to Track Domain Prices: My Journey Creating TLDSpy API