> ## Documentation Index
> Fetch the complete documentation index at: https://docs.signalhire.com/llms.txt
> Use this file to discover all available pages before exploring further.

# API Authentication

> To access the SignalHire API, you need to authenticate using an API key. The API key serves as a unique identifier and ensures that only authorized requests are processed.

All requests must include the API key in the request header.

## Obtaining an API Key

1. Register for a [SignalHire account](https://www.signalhire.com/registration?package=trial)
2. Open the left sidebar and navigate to **Other tools → Integrations & API**
3. Click **Create new API Key**, then copy the generated key using the copy icon next to it

<Frame caption="Integrations & API under Other tools in the left sidebar">
  <img src="https://mintcdn.com/signalhire/pod96eCHEkujyXWp/images/api-integrations.png?fit=max&auto=format&n=pod96eCHEkujyXWp&q=85&s=9a37435513cfc031ec086dc84d5eab69" alt="Integrations and API in the left sidebar" width="652" height="602" data-path="images/api-integrations.png" />
</Frame>

<Frame caption="Creating and copying your API key">
  <img src="https://mintcdn.com/signalhire/pod96eCHEkujyXWp/images/api-key.png?fit=max&auto=format&n=pod96eCHEkujyXWp&q=85&s=969c7d0df9ebfcc286321f02cb4bb357" alt="Create new API Key button and copy icon" width="1755" height="1086" data-path="images/api-key.png" />
</Frame>

## Using the API Key

Include the `apikey` header in every request:

<CodeGroup>
  ```bash cURL theme={null}
  curl -X POST https://www.signalhire.com/api/v1/candidate/search \
  -H 'apikey: your_secret_api_key' \
  --data '{"items": [...], "callbackUrl": "https://yourdomain.com/callback"}'
  ```

  ```python Python theme={null}
  import requests

  response = requests.post(
  "https://www.signalhire.com/api/v1/candidate/search",
  headers={"apikey": "your_secret_api_key"},
  json={
  "items": [...],
  "callbackUrl": "https://yourdomain.com/callback"
  }
  )
  ```

  ```javascript Node.js theme={null}
  const axios = require('axios');

  const response = await axios.post(
  'https://www.signalhire.com/api/v1/candidate/search',
  {
      items: [...],
      callbackUrl: 'https://yourdomain.com/callback'
  },
  {
      headers: { apikey: 'your_secret_api_key' }
  }
  );
  ```

  ```java Java theme={null}
  import java.net.http.*;
  import java.net.URI;

  HttpClient client = HttpClient.newHttpClient();

  HttpRequest request = HttpRequest.newBuilder()
  .uri(URI.create("https://www.signalhire.com/api/v1/candidate/search"))
  .header("apikey", "your_secret_api_key")
  .header("Content-Type", "application/json")
  .POST(HttpRequest.BodyPublishers.ofString(
  "{\"items\": [...], \"callbackUrl\": \"https://yourdomain.com/callback\"}"
  ))
  .build();

  HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
  ```

  ```ruby Ruby theme={null}
      require 'net/http'
      require 'json'

      uri = URI('https://www.signalhire.com/api/v1/candidate/search')
      http = Net::HTTP.new(uri.host, uri.port)
      http.use_ssl = true

      request = Net::HTTP::Post.new(uri)
      request['apikey'] = 'your_secret_api_key'
      request['Content-Type'] = 'application/json'
      request.body = {
      items: [...],
      callbackUrl: 'https://yourdomain.com/callback'
  }.to_json

      response = http.request(request)
  ```
</CodeGroup>

<Warning>
  API keys must be kept secure. Exposing a key in public repositories or sharing it with unauthorized parties allows others to make API calls consuming paid credits.
</Warning>

## Checking Remaining Credits

The `X-Credits-Left` header is included in every API response and shows the current credit balance.

```http theme={null}
    HTTP/2 201
    Content-Type: application/json
    X-Credits-Left: 243
```

Credits can also be checked explicitly — see [Get Remaining Credits](/person-api/credits).