You can add a Retryer in the FeignClientConfig

@Configuration
public class FeignClientConfig {

    @Bean
    public Retryer retryer() {
        return new Custom();
    }

}

class Custom implements Retryer {

    private final int maxAttempts;
    private final long backoff;
    int attempt;

    public Custom() {
        this(2000, 3);
    }

    public Custom(long backoff, int maxAttempts) {
        this.backoff = backoff;
        this.maxAttempts = maxAttempts;
        this.attempt = 1;
    }

    public void continueOrPropagate(RetryableException e) {
        if (attempt++ >= maxAttempts) {
            throw e;
        }

        try {
            Thread.sleep(backoff);
        } catch (InterruptedException ignored) {
            Thread.currentThread().interrupt();
        }
    }

    @Override
    public Retryer clone() {
        return new Custom(backoff, maxAttempts);
    }
}

Updated with sample Retryer example config based on the Retryer.Default.

Without additional configuration, Feign will retry on IOExceptions only. If you wish to retry based on status codes, you will need to create an ErrorDecoder that throws a RetryableException or derivative of, in order to trigger a retry.

Here is simple example:

class MyErrorDecoder implements ErrorDecoder {
    public Exception decode(String methodKey, Response response) {
        if (response.status() == 503) {
            throw new RetryableException(
                response.status(), 
                "Service Unavailable", 
                response.request().httpMethod(), 
                null);
        } else {
            return new RuntimeException("error");
        }
    }
}

For more examples, take a look at the Error Handling documentation.

Yes, here is the formula

long nextMaxInterval() {
      long interval = (long) (period * Math.pow(1.5, attempt - 1));
      return interval > maxPeriod ? maxPeriod : interval;
}

The number of attempt will decide how long the interval is and it's not over maxPeriod