SMS API integration seems simple — send a number, get delivery confirmation. But production SMS systems in Nigeria encounter edge cases and failure modes that catch developers off guard. These best practices, learned from real Nigerian production deployments, prevent the most common problems.
Never Hardcode API Keys
API keys in source code lead to secrets exposure in version control and unauthorized usage. Store API keys in environment variables or secret management services. Rotate keys immediately if exposed. Use different API keys for development, staging, and production environments.
Validate Phone Numbers Before Sending
Invalid phone numbers waste API credits and generate errors. Implement Nigerian phone number validation that: verifies the number is 11 digits (starting with 0) or 13 digits (starting with 234), confirms the prefix belongs to a valid Nigerian network, and rejects obvious test numbers before they reach the API.
Implement Exponential Backoff for Retries
Temporary API failures should trigger retries with exponential backoff — wait 1 second, then 2 seconds, then 4 seconds between retries, with a maximum retry count. Never retry indefinitely. Log failed sends after maximum retries for manual investigation.
Balance Management
Running out of SMS balance during a critical OTP or alert event is a production incident. Monitor your account balance via the API and set automated alerts at threshold levels (e.g., alert when balance drops below 10,000 messages remaining). Consider auto top-up for high-volume applications where balance exhaustion would cause a service outage.
Test All Error Paths
Happy path testing only reveals a fraction of potential issues. Test: insufficient balance behaviour, invalid phone number handling, network timeout handling, webhook signature validation, and DND number filtering. Each error path needs explicit handling in your application.
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