API Integration Checklist | MacraSMS Developer Guide

1. Authentication Setup

Proper authentication is the foundation of secure API integration. Follow these steps:

Generate API Key: Create a unique API key from your MacraSMS dashboard under Settings > API Keys
Store Securely: Never hardcode API keys in source code. Use environment variables or secrets management tools
Verify Sender ID: Ensure your registered Sender ID matches exactly what you pass in API requests
Test Credentials: Make a test request using sandbox credentials before switching to production
Rotate Regularly: Plan to rotate API keys every 90 days as a security best practice

Critical Security Rule

Never commit API keys to version control systems like Git. Use .env files excluded from repositories or cloud-native secrets managers.

2. Environment Configuration

Configure your application environments correctly:

Setting	Sandbox	Production
Base URL	`https://sms.macrasms.com/api/v1/sandbox/`	`https://sms.macrasms.com/api/v1/`
API Key	Sandbox-specific key	Production API key
Sender ID	TESTID (pre-approved)	Your registered brand Sender ID
Rate Limit	10 req/min	100 req/min (standard tier)
Billing	Free test credits	Deducted from account balance

3. Error Handling

Implement comprehensive error handling for all API responses:

HTTP 400: Validate request parameters before sending. Log invalid requests for debugging
HTTP 401: Trigger immediate alert if authentication fails. Check API key validity and expiration
HTTP 402: Handle insufficient balance gracefully. Notify admin and pause non-critical sends
HTTP 429: Implement exponential backoff when rate limited. Never ignore rate limit headers
HTTP 5xx: Retry with exponential backoff up to 3 attempts. Log server errors for monitoring
Timeout: Set 30-second timeout for all requests. Handle timeouts as transient failures

// Example: Robust error handling pattern
try {
    const response = await fetch(apiUrl, options);
    
    if (!response.ok) {
        switch(response.status) {
            case 401: throw new AuthError('Invalid credentials');
            case 402: throw new BalanceError('Insufficient funds');
            case 429: throw new RateLimitError('Rate limited');
            default: throw new ApiError(`HTTP ${response.status}`);
        }
    }
    
    return await response.json();
} catch (error) {
    logger.error('SMS API failed', { error: error.message });
    // Implement fallback or notification logic
}
            

4. Retry Logic

Transient failures are inevitable. Implement smart retry strategies:

Exponential Backoff: Start with 1s delay, double after each attempt (1s → 2s → 4s)
Maximum Retries: Cap at 3 attempts to avoid infinite loops
Jitter: Add random jitter (±25%) to prevent thundering herd problems
Idempotency: Use unique message IDs to prevent duplicate sends on retry
Circuit Breaker: Stop retrying after consecutive failures to protect system stability

Retry Caution

Only retry on transient errors (5xx, timeouts, 429). Never retry on 400, 401, or 402 errors - these require manual intervention.

5. Webhook Setup

Configure webhooks for real-time delivery status updates:

Endpoint Security: Protect webhook endpoints with signature verification using shared secret
Response Time: Respond within 5 seconds to avoid carrier timeout retries
Idempotent Processing: Handle duplicate webhook deliveries gracefully using message IDs
Error Logging: Log all webhook payloads for debugging and audit purposes
Fallback Polling: Implement periodic status polling as backup if webhooks fail

6. Testing Procedures

Thoroughly test before going live:

Sandbox Testing: Send test messages to verified numbers using sandbox credentials
Error Simulation: Test all error scenarios (invalid key, insufficient balance, invalid number)
Bulk Testing: Send batch of 10+ messages to verify bulk endpoint behavior
Webhook Testing: Verify webhook reception and processing with test delivery statuses
Load Testing: Simulate peak traffic volume to validate rate limiting and performance
User Acceptance: Have stakeholders verify message content, timing, and opt-out functionality

7. Security Hardening

Protect your integration against common vulnerabilities:

Input Validation: Sanitize all phone numbers and message content before API calls
HTTPS Only: Never make API calls over HTTP. Enforce TLS 1.2+
Secret Management: Rotate API keys quarterly. Revoke compromised keys immediately
Access Control: Restrict API access to authorized services only via IP whitelisting
Audit Logging: Log all API requests with timestamps, IPs, and response codes
Dependency Scanning: Regularly update SDKs and dependencies to patch security vulnerabilities

Security Bonus

Enable two-factor authentication on your MacraSMS dashboard account to add an extra layer of protection for API key management.

8. Pre-Launch Verification

Final checklist before enabling production traffic:

✅ Production API key configured and tested
✅ Registered Sender ID approved and active
✅ Sufficient account balance for expected volume
✅ Error handling and retry logic implemented
✅ Webhook endpoint secured and tested
✅ Monitoring and alerting configured for failures
✅ Opt-out mechanism functional and compliant
✅ Privacy notice displayed at consent capture points
✅ Team trained on API usage and incident response
✅ Rollback plan documented for emergency situations

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