# Add a link domain

Source: https://jointextkit.com/docs/api/link-domains/create
Index: https://jointextkit.com/llms.txt

`POST /v1/link-domains`

Add a subdomain of your own (links.example.com) to carry short links (`shorten_links` on POST /messages). Carriers filter shared shorteners, so short links only ever go on your own domain. The response lists two DNS records to add: a CNAME to our link host and a TXT that proves the domain is yours. Then call POST /link-domains/{id}/verify. Once both records check out, verify turns it on (`active`). A bare domain, one of ours, a public shortener or a look-alike of a known brand is refused. Recorded in the audit log as link_domain.created. Scope: links.

Send your API key as a bearer token: `Authorization: Bearer ssms_sk_...`. Test keys run this endpoint against the [sandbox](/docs/sandbox); see [Authentication](/docs/authentication) for key modes and scopes.

## Request body

JSON (`Content-Type: application/json`).

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `domain` | string | Yes | Example: `links.example.com`. |

## Responses

| Status | Meaning | Body |
| --- | --- | --- |
| 201 | Added, with the DNS records to create | `LinkDomain` |
| 400 | Not a usable domain, or 3 already | `Error` |
| 401 | Missing, malformed, or revoked API key | `Error` |
| 402 | Billable live calls only: the prepaid credit balance cannot cover the call (insufficient_credits); nothing was done or charged | `Error` |
| 409 | Already on this account or another (invalid_state) | `Error` |
| 429 | Rate limit or quota exceeded | `Error` |

### 201: `LinkDomain` fields

| Field | Type | Description |
| --- | --- | --- |
| `id` | string | Example: `ld_a1B2c3D4e5F6`. |
| `object` | `link_domain` |  |
| `domain` | string | Example: `links.example.com`. |
| `status` | `pending_dns`, `dns_verified`, `active` | `pending_dns`: add the records and verify. `dns_verified`: the records check out and it is being turned on. `active`: `shorten_links` uses it. |
| `dns_records` | array of object | The records to create at your DNS host. |
| `dns_records[].type` | `CNAME`, `TXT` |  |
| `dns_records[].name` | string | Example: `links.example.com`. |
| `dns_records[].value` | string | Example: `links.jointextkit.com`. |
| `dns_records[].purpose` | string |  |
| `created_at` | string (date-time) |  |
| `verified_at` | string (date-time) | Nullable. |
| `activated_at` | string (date-time) | Nullable. |
| `last_check` | object | Nullable. |
| `last_check.at` | string (date-time) |  |
| `last_check.cname` | boolean |  |
| `last_check.txt` | boolean |  |

## Errors

| Status | When |
| --- | --- |
| 400 | Not a usable domain, or 3 already |
| 401 | Missing, malformed, or revoked API key |
| 402 | Billable live calls only: the prepaid credit balance cannot cover the call (insufficient_credits); nothing was done or charged |
| 409 | Already on this account or another (invalid_state) |
| 429 | Rate limit or quota exceeded |

Every error has the same JSON shape, and `request_id` matches the `X-Request-Id` response header. [Errors](/docs/errors) lists every code and what to do about it.

```json
{
  "error": {
    "code": "invalid_request",
    "message": "What went wrong, in plain words.",
    "param": "the_field",
    "request_id": "req_a1B2c3D4e5F6g7H8"
  }
}
```

## Examples

### Node.js

The Node.js SDK does not wrap this endpoint yet; call it over HTTP.

```javascript
const res = await fetch('https://api.jointextkit.com/v1/link-domains', {
  method: 'POST',
  headers: {
    Authorization: `Bearer ${process.env.TEXTKIT_API_KEY}`,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "domain": "links.example.com"
  }),
});

if (!res.ok) throw new Error((await res.json()).error.message);
const data = await res.json();
```

### PHP

```php
<?php

$ch = curl_init('https://api.jointextkit.com/v1/link-domains');
curl_setopt_array($ch, [
    CURLOPT_CUSTOMREQUEST => 'POST',
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        'Authorization: Bearer ' . getenv('TEXTKIT_API_KEY'),
        'Content-Type: application/json',
    ],
    CURLOPT_POSTFIELDS => json_encode([
        'domain' => 'links.example.com',
    ]),
]);

$data = json_decode(curl_exec($ch), true);
```

### Python

The Python SDK does not wrap this endpoint yet; call it over HTTP.

```python
import json, os, urllib.request

req = urllib.request.Request(
    "https://api.jointextkit.com/v1/link-domains",
    method="POST",
    headers={
        "Authorization": f"Bearer {os.environ['TEXTKIT_API_KEY']}",
        "Content-Type": "application/json",
    },
    data=json.dumps({
        "domain": "links.example.com"
    }).encode(),
)
with urllib.request.urlopen(req) as res:
    data = json.load(res)
```

### Ruby

```ruby
require "net/http"
require "json"

uri = URI("https://api.jointextkit.com/v1/link-domains")
req = Net::HTTP::Post.new(uri)
req["Authorization"] = "Bearer #{ENV["TEXTKIT_API_KEY"]}"
req["Content-Type"] = "application/json"
req.body = {
  "domain": "links.example.com"
}.to_json

res = Net::HTTP.start(uri.host, uri.port, use_ssl: true) { |http| http.request(req) }
data = JSON.parse(res.body)
```

### Go

```go
package main

import (
	"fmt"
	"io"
	"net/http"
	"os"
	"strings"
)

func main() {
	body := strings.NewReader(`{
	  "domain": "links.example.com"
	}`)
	req, _ := http.NewRequest("POST", "https://api.jointextkit.com/v1/link-domains", body)
	req.Header.Set("Authorization", "Bearer "+os.Getenv("TEXTKIT_API_KEY"))
	req.Header.Set("Content-Type", "application/json")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	data, _ := io.ReadAll(res.Body)
	fmt.Println(res.Status, string(data))
}
```

### Rust

```rust
// cargo add reqwest --features blocking,json
// cargo add serde_json
use serde_json::json;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let key = std::env::var("TEXTKIT_API_KEY")?;
    let res = reqwest::blocking::Client::new()
        .post("https://api.jointextkit.com/v1/link-domains")
        .bearer_auth(key)
        .json(&json!({
          "domain": "links.example.com"
        }))
        .send()?
        .error_for_status()?;
    let data: serde_json::Value = res.json()?;
    println!("{data}");
    Ok(())
}
```

### Java

```java
import java.net.URI;
import java.net.http.*;

public class Main {
    public static void main(String[] args) throws Exception {
        var request = HttpRequest.newBuilder(URI.create("https://api.jointextkit.com/v1/link-domains"))
            .header("Authorization", "Bearer " + System.getenv("TEXTKIT_API_KEY"))
            .header("Content-Type", "application/json")
            .method("POST", HttpRequest.BodyPublishers.ofString("""
                {
                  "domain": "links.example.com"
                }
                """))
            .build();

        var response = HttpClient.newHttpClient().send(request, HttpResponse.BodyHandlers.ofString());
        System.out.println(response.statusCode() + " " + response.body());
    }
}
```

### .NET

```csharp
using System.Net.Http.Headers;
using System.Text;

var http = new HttpClient();
http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(
    "Bearer", Environment.GetEnvironmentVariable("TEXTKIT_API_KEY"));

var body = new StringContent("""
    {
      "domain": "links.example.com"
    }
    """, Encoding.UTF8, "application/json");
var res = await http.PostAsync("https://api.jointextkit.com/v1/link-domains", body);
res.EnsureSuccessStatusCode();

var data = await res.Content.ReadAsStringAsync();
```

### cURL

```bash
curl -X POST "https://api.jointextkit.com/v1/link-domains" \
  -H "Authorization: Bearer $TEXTKIT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "domain": "links.example.com"
}'
```

## Related

- [All link domains endpoints](/docs/api#link-domains)
- [API reference](/docs/api)