Open Topo Data Getting Started: API Access & First Call (2026)

Getting started overview

This guide provides a structured approach to initiating development with Open Topo Data, focusing on account creation, API key retrieval, and executing a foundational API request. Open Topo Data offers access to global elevation and geocoding services, built upon open-source datasets such as OpenStreetMap and Open-Elevation. The service includes a free tier, allowing up to 1,000 requests per day, making it suitable for hobbyist applications and initial development phases. Subsequent paid tiers provide increased request volumes, starting at $10 per month for 25,000 requests.

The primary objective is to enable a developer to make a successful API call and receive a valid response, confirming basic connectivity and authentication. This process typically involves:

1. Registering for an Open Topo Data account.
2. Obtaining the unique API key associated with the account.
3. Constructing and executing an API request, such as an elevation query, using the obtained key.
4. Verifying the API response for correctness and expected data format.

The following table summarizes the initial steps:

Create an account and get keys

To begin utilizing Open Topo Data, an account registration is required to obtain an API key. This key acts as an authentication token for all your API requests, ensuring proper usage tracking and access control. The registration process is typically straightforward and involves providing an email address and creating a password.

1. Navigate to the Open Topo Data website: Open your web browser and go to the Open Topo Data homepage.

2. Locate the registration or signup option: Look for buttons or links labeled "Sign Up," "Register," or "Get Started."

3. Complete the registration form: Provide the requested information, which typically includes an email address and a secure password. Agree to any terms of service or privacy policies.

4. Verify your email (if required): Some services send a verification email to confirm the account. Follow the instructions in the email to activate your account.

5. Log in to your account: Once registered and verified, log in to your newly created Open Topo Data account.

6. Access your API key: Within your account dashboard, there should be a section specifically for API keys, credentials, or developer settings. Your unique API key will be displayed there. It is crucial to treat this key as sensitive information, similar to a password, to prevent unauthorized access to your account and usage limits.

The API key is a string of alphanumeric characters. For example, it might look like pk.eyJ1IjoiYXBpc3BpbmUiLCJhIjoiY2sxczNlM2Q2MWZlNzQ4YjEwMjM0NTY3ODkwIn0.ABCDE12345FGHIJ67890 (this is an example format, not a real key). Copy this key, as it will be included in every API request you make.

Your first request

With an API key in hand, you can now construct and execute your first API request. This example demonstrates fetching elevation data for a specific geographical point, a common initial use case for Open Topo Data.

Elevation API Example

The Open Topo Data Elevation API allows you to retrieve elevation data for one or more latitude/longitude coordinates. The base URL for the API is https://api.opentopodata.com/v1/. For elevation, you'll typically use the /elevation endpoint, specifying a dataset and locations.

Request Parameters:

• locations: A pipe-separated list of latitude,longitude pairs (e.g., 34.0522,-118.2437|40.7128,-74.0060).
• dataset: The elevation dataset to query (e.g., srtm90m for SRTM 90m resolution data).
• api_key: Your unique Open Topo Data API key.

Example using curl:

Replace YOUR_API_KEY with the actual API key obtained from your Open Topo Data account. This example requests elevation data for the coordinates 34.0522,-118.2437 (Los Angeles) using the srtm90m dataset.

curl "https://api.opentopodata.com/v1/elevation?locations=34.0522,-118.2437&dataset=srtm90m&api_key=YOUR_API_KEY"

Expected JSON Response:

A successful request will return a JSON object containing an array of results, each with the input location and its corresponding elevation.

{
  "results": [
    {
      "location": {
        "lat": 34.0522,
        "lng": -118.2437
      },
      "elevation": 86.8,
      "dataset": "srtm90m"
    }
  ],
  "status": "OK"
}

The elevation value is in meters. The status field indicates the success or failure of the request. A "status": "OK" confirms a successful data retrieval.

Common next steps

After successfully making your initial API call, consider these next steps to further integrate Open Topo Data into your application:

1. Explore other API endpoints: Open Topo Data offers various endpoints beyond basic elevation, including geocoding and reverse geocoding. Review the Open Topo Data API documentation to understand the full range of capabilities and available datasets.

2. Implement error handling: Integrate robust error handling into your application to gracefully manage API rate limits, invalid requests, or service unavailability. The API typically returns HTTP status codes (e.g., 400 Bad Request, 403 Forbidden, 429 Too Many Requests) and descriptive JSON error messages.

3. Secure your API key: Ensure your API key is not exposed in client-side code or publicly accessible repositories. For web applications, consider using a backend proxy to make API calls, or store keys securely in environment variables for server-side applications. Best practices for API key security are detailed by various platforms, such as Google Maps Platform API key security guidelines.

4. Monitor usage: Keep track of your API request volume through your Open Topo Data account dashboard to stay within your free tier limits or manage your paid subscription effectively.

5. Choose appropriate datasets: Different datasets offer varying resolutions and coverage. Select the dataset that best fits your application's precision requirements and geographical scope. For example, srtm90m is global but lower resolution, while other datasets might offer higher resolution for specific regions.

6. Consider client libraries: For more complex applications, using a dedicated HTTP client library in your chosen programming language (e.g., Python's requests, Node.js's axios, Java's HttpClient) can simplify API interactions, including request construction, parameter encoding, and JSON parsing.

Troubleshooting the first call

Encountering issues during your first API call is common. Here are some troubleshooting steps and common problems:

• Incorrect API Key:

  • Symptom: 403 Forbidden or Invalid API Key error message.
  • Solution: Double-check that you have copied the entire API key correctly from your Open Topo Data dashboard. Ensure there are no leading or trailing spaces.

• Missing API Key:

  • Symptom: 401 Unauthorized or API key missing error.
  • Solution: Verify that the api_key parameter is included in your request URL with your key as its value.

• Invalid Parameters:

  • Symptom: 400 Bad Request with a message indicating invalid coordinates, dataset, or format.
  • Solution: Review the Open Topo Data API documentation for the specific endpoint you are using. Ensure latitude and longitude are in the correct order (latitude,longitude) and within valid ranges. Check that the dataset name is spelled correctly and is supported. For example, latitude ranges from -90 to +90, and longitude from -180 to +180, as defined by the Geolocation API specification.

• Rate Limit Exceeded:

  • Symptom: 429 Too Many Requests error.
  • Solution: You have exceeded the request limit for your current plan (e.g., 1,000 requests/day for the free tier). Wait until the limit resets or consider upgrading your plan. Implement exponential backoff for retries in your application.

• Network Connectivity Issues:

  • Symptom: Connection timeouts or host unreachable errors.
  • Solution: Verify your internet connection. If making requests from a server, check firewall rules or proxy settings that might be blocking outbound connections to api.opentopodata.com.

• Incorrect Endpoint or URL:

  • Symptom: 404 Not Found error.
  • Solution: Ensure the base URL (https://api.opentopodata.com/v1/) and the specific endpoint path (e.g., /elevation) are correct and accurately typed.

• JSON Parsing Errors:

  • Symptom: Your application fails to parse the API response.
  • Solution: Verify that the response is indeed valid JSON. Use online JSON validators or your programming language's JSON parsing libraries (e.g., JSON.parse() in JavaScript, json.loads() in Python) and ensure you handle potential errors during parsing.

Refer to the official Open Topo Data documentation for the most up-to-date error codes and troubleshooting guides specific to their API implementation.