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Overview

The Semust API uses custom header authentication. All requests must include two authentication headers with your API credentials.

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Required Headers

HeaderTypeDescription
SEMUST-API-USERstringYour API user username
SEMUST-API-PASSWORDstringYour API user password
Both headers are required. Missing either header will result in a 401 error.

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Creating API Users

To create API credentials:
1

Access the Dashboard

Go to the API Access page in your dashboard.
2

Create API User

Click “Create API User” to generate new credentials.
3

Copy Credentials

Copy the username and password. Use them in the SEMUST-API-USER and SEMUST-API-PASSWORD headers in your requests.
You can create multiple API users per account for different applications or environments.
Security: Never expose your API credentials in client-side code or public repositories. Store them securely in environment variables.

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Code Examples

curl -X POST https://data.semust.com/v1/serp \
  -H "Content-Type: application/json" \
  -H "SEMUST-API-USER: your_username" \
  -H "SEMUST-API-PASSWORD: your_password" \
  -d '{"keyword": "best seo tools"}'

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Authentication Errors

If authentication fails, you will receive a 401 status code with the following error:
Error Response
{
  "error": "Authentication failed — invalid username or password",
  "code": "INVALID_API_KEY"
}
StatusCodeDescription
401INVALID_API_KEYThe provided credentials are invalid
Double-check that both SEMUST-API-USER and SEMUST-API-PASSWORD headers are present and contain the correct values from your API Access page.