Rate Limits

FHIRfly uses rate limiting to ensure fair usage and maintain service quality for all users.

Default Limits

Plan	Rate Limit	Monthly Quota
Free	10 req/sec	10,000 requests
Developer	50 req/sec	100,000 requests
Pro	100 req/sec	250,000 requests
Business	200 req/sec	500,000 requests
Enterprise	Custom	Custom

See our Pricing page for full plan details.

Rate Limit Headers

Every API response includes headers showing your current rate limit status:

X-RateLimit-Limit: 120
X-RateLimit-Remaining: 115
X-RateLimit-Reset: 1704067200

Header	Description
`X-RateLimit-Limit`	Maximum requests per minute
`X-RateLimit-Remaining`	Requests remaining in current window
`X-RateLimit-Reset`	Unix timestamp when the window resets

Handling Rate Limits

When you exceed your rate limit, the API returns a 429 Too Many Requests response:

{
  "error": "rate_limit_exceeded",
  "error_description": "Rate limit exceeded. Try again in 45 seconds.",
  "retry_after": 45
}

Best Practices

Implement exponential backoff - Wait longer between retries
Use batch endpoints - Fetch multiple items in one request
Cache responses - NDC and NPI data changes infrequently
Monitor the headers - Slow down before hitting limits

Example: Exponential Backoff

async function fetchWithRetry(url, options, maxRetries = 3) {
  for (let i = 0; i < maxRetries; i++) {
    const response = await fetch(url, options);

    if (response.status === 429) {
      const retryAfter = response.headers.get('Retry-After') || Math.pow(2, i);
      await new Promise(resolve => setTimeout(resolve, retryAfter * 1000));
      continue;
    }

    return response;
  }
  throw new Error('Max retries exceeded');
}

Batch Requests

Use batch endpoints to fetch multiple items efficiently:

curl -X POST "https://api.fhirfly.io/v1/ndc/_batch" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"codes": ["0069-0151-01", "0069-0152-01", "0069-0153-01"]}'

Batch requests count as 1 request toward your rate limit, regardless of how many items you fetch.

Quota Management

Track your monthly usage in the Dashboard. You'll receive email alerts at:

80% of quota used
90% of quota used
100% of quota used (requests will be rejected)