# How to Obtain Free API Keys for Integration Testing
To run integration tests with real external APIs, you need to obtain free API keys for the following services:
| Service | Free Tier | Sign Up URL |
|------------------------|------------------------|------------------------------------------------------------------|
| **FRED** | 120,000 calls/day | [Get FRED API Key](https://fred.stlouisfed.org/docs/api/api_key.html) |
| **BLS** | 500 calls/day | [Get BLS API Key](https://www.bls.gov/developers/api_signature_v2.htm) |
| **Alpha Vantage** | 25 calls/day | [Get Alpha Vantage API Key](https://www.alphavantage.co/support/#api-key) |
| **Census Bureau** | No limit | [Get Census API Key](https://api.census.gov/data/key_signup.html) |
| **NASDAQ Data Link** | 50 calls/day | [Get NASDAQ Data Link API Key](https://data.nasdaq.com/sign-up) |
## Step-by-Step Instructions
1. **FRED (Federal Reserve Economic Data)**
- Go to the [FRED API Key page](https://fred.stlouisfed.org/docs/api/api_key.html).
- Log in or create an account.
- Request your API key and copy it.
2. **BLS (Bureau of Labor Statistics)**
- Visit the [BLS API registration page](https://www.bls.gov/developers/api_signature_v2.htm).
- Fill out the registration form.
- Your API key will be sent to your email.
3. **Alpha Vantage**
- Go to the [Alpha Vantage API key page](https://www.alphavantage.co/support/#api-key).
- Enter your email address.
- You will receive your API key by email.
4. **Census Bureau**
- Visit the [Census API key signup page](https://api.census.gov/data/key_signup.html).
- Fill out the form and submit.
- Your API key will be displayed instantly.
5. **NASDAQ Data Link (formerly Quandl)**
- Go to the [NASDAQ Data Link sign-up page](https://data.nasdaq.com/sign-up).
- Create an account.
- After logging in, find your API key in your account settings.
## Add Keys to Your .env File
Once you have your keys, add them to your `.env` file like this:
```
FRED_API_KEY=your_fred_api_key_here
BLS_API_KEY=your_bls_api_key_here
ALPHA_VANTAGE_API_KEY=your_alpha_vantage_key_here
CENSUS_API_KEY=your_census_key_here
NASDAQ_DATA_LINK_API_KEY=your_nasdaq_key_here
```
You can now run integration tests as described in the [API Integration Testing Guide](./api-reference.md).
