Troubleshooting Guide: 10 Common Gateway Integration Errors

Gateway integration errors can bring your applications to a grinding halt, frustrating users and costing valuable time and resources. Whether you're dealing with payment gateways, API gateways, or LLM gateways, understanding common errors and their solutions is crucial for maintaining smooth operations.

As developers increasingly rely on gateway services to connect different systems, the complexity of troubleshooting has grown exponentially. This comprehensive guide walks you through the 10 most common gateway integration errors and provides practical solutions to get your systems back online quickly.

1. Transaction Declines

Transaction declines are among the most frustrating errors for both developers and end-users. These occur when payments are rejected by the gateway or bank, often due to insufficient funds, incorrect card details, or suspected fraud.

Common Causes:

  • Insufficient funds in the customer's account

  • Incorrect or expired card information

  • Fraud prevention systems flagging legitimate transactions

  • Mismatched billing information

Resolution Steps:

  • Verify all payment information is correct and up-to-date

  • Review and adjust fraud prevention settings to reduce false positives

  • Implement retry logic with exponential backoff

  • Avoid repeated retries with invalid cards to prevent account flags

For LLM applications processing payments or handling sensitive financial data, Requesty's guardrails can help ensure compliance and security while maintaining smooth transaction flows.

2. Gateway Connection Issues

Connection failures between your application and the gateway can cause intermittent errors that are difficult to diagnose. These issues often manifest as timeout errors or complete connection failures.

Common Causes:

  • Network connectivity problems

  • Firewall blocking required ports

  • DNS resolution failures

  • Gateway service outages

Resolution Steps:

  • Check network connectivity and DNS resolution

  • Monitor gateway status dashboards for service interruptions

  • Ensure required firewall ports and FQDNs are open

  • Implement connection pooling and retry mechanisms

When working with LLM gateways, Requesty's failover policies automatically route requests to backup models when connection issues occur, ensuring your AI applications remain responsive even during gateway outages.

3. API Integration Errors

API integration errors are particularly common in modern applications, especially with the rise of serverless architectures and complex API Gateway setups.

Common Causes:

  • Incorrect or expired API keys

  • Outdated SDK libraries

  • Improper response formatting

  • Authentication failures

Resolution Steps:

  • Verify and regularly rotate API credentials

  • Keep SDK libraries updated to the latest versions

  • Ensure response formats match gateway requirements (especially for AWS API Gateway which expects specific JSON structure)

  • Test integrations thoroughly in sandbox environments

For developers working with multiple LLM APIs, Requesty's unified API eliminates the need to manage different integration patterns across 160+ models, significantly reducing API integration errors.

4. Currency Mismatch

Currency-related errors occur when the transaction currency doesn't align with gateway or merchant settings, leading to failed transactions or incorrect pricing.

Common Causes:

  • Misaligned currency settings between store and gateway

  • Incorrect currency conversion logic

  • Regional settings conflicts

  • Multi-currency configuration errors

Resolution Steps:

  • Align currency settings across all systems

  • Implement proper currency validation before processing

  • Update checkout processes for correct currency handling

  • Test with multiple currency scenarios

When building global AI applications, proper currency handling becomes even more critical. Requesty's enterprise features include user budgets and spend limits that automatically handle multi-currency scenarios.

5. Fraud Alerts and Holds

Overly aggressive fraud prevention can block legitimate transactions, creating a poor user experience and lost revenue.

Common Causes:

  • Strict fraud prevention rules

  • Unusual transaction patterns

  • Geographic restrictions

  • Velocity checks triggering false positives

Resolution Steps:

  • Balance fraud prevention settings between security and user experience

  • Implement manual review processes for flagged transactions

  • Use machine learning-based fraud detection when available

  • Maintain allowlists for trusted customers

Requesty's security features include intelligent guardrails that can help detect and prevent fraudulent API usage while minimizing false positives.

6. Payment Processing Delays

Processing delays can occur during high-traffic periods or due to backend infrastructure issues, leading to timeouts and failed transactions.

Common Causes:

  • High transaction volume during peak times

  • Network latency issues

  • Backend processing bottlenecks

  • Insufficient gateway resources

Resolution Steps:

  • Monitor and optimize for peak transaction times

  • Implement queue-based processing for non-critical operations

  • Use asynchronous processing where appropriate

  • Scale gateway resources based on demand

For LLM applications, Requesty's load balancing automatically distributes requests across multiple models, preventing delays during high-traffic periods.

7. Security Certificate Errors

SSL/TLS certificate issues can completely block secure communications, making payment processing and API calls impossible.

Common Causes:

  • Expired certificates

  • Invalid certificate chains

  • Hostname mismatches

  • Outdated TLS versions

Resolution Steps:

  • Set up automated certificate renewal

  • Validate certificate chains regularly

  • Ensure proper hostname configuration

  • Update to supported TLS versions

Requesty's secure infrastructure handles all certificate management automatically, ensuring your LLM API calls are always encrypted and secure.

8. Configuration Errors

Misconfigured gateway settings are often the root cause of persistent integration issues that can be difficult to diagnose.

Common Causes:

  • Incorrect endpoint URLs

  • Wrong environment settings (production vs. sandbox)

  • Missing required parameters

  • Improper webhook configurations

Resolution Steps:

  • Document all configuration settings

  • Use configuration management tools

  • Implement configuration validation

  • Maintain separate configs for different environments

With Requesty's smart routing, configuration complexity is reduced as the platform automatically selects the best model for each task without manual configuration.

9. Refund and Chargeback Issues

Problems with processing refunds or handling chargebacks can damage customer relationships and lead to compliance issues.

Common Causes:

  • Procedural errors in refund processing

  • Missing transaction records

  • Timeout during refund operations

  • Incorrect refund amounts

Resolution Steps:

  • Follow established procedures for refunds and chargebacks

  • Maintain comprehensive transaction logs

  • Implement idempotent refund operations

  • Set up automated reconciliation processes

For AI applications handling customer service, proper refund handling is crucial. Requesty's request metadata feature helps track all API calls for audit and dispute resolution.

10. Connectivity and Routing Issues

Network-level problems can cause intermittent failures that are particularly challenging to debug.

Common Causes:

  • Misconfigured IP addresses or subnet masks

  • Routing table errors

  • DNS propagation delays

  • Proxy configuration issues

Resolution Steps:

  • Use diagnostic tools like ping, traceroute, and tcpdump

  • Verify gateway IP and routing settings

  • Check proxy configurations and authentication

  • Monitor network performance metrics

Requesty's routing optimizations include automatic failover and intelligent routing that work around connectivity issues transparently.

Best Practices for Gateway Error Prevention

Monitoring and Logging

Comprehensive monitoring is your first line of defense against gateway errors:

  • Collect and analyze all gateway logs

  • Set up real-time alerts for critical errors

  • Use distributed tracing for complex integrations

  • Monitor key performance indicators

Requesty's analytics dashboard provides detailed insights into all your LLM API calls, making it easy to spot and diagnose issues before they impact users.

Error Handling Strategies

Robust error handling can turn potential failures into minor hiccups:

  • Implement exponential backoff for retries

  • Use circuit breakers to prevent cascade failures

  • Provide meaningful error messages to users

  • Log all errors with sufficient context for debugging

Security Best Practices

Security should never be an afterthought:

  • Apply strict firewall rules

  • Use API key rotation policies

  • Implement rate limiting

  • Enable audit logging for all transactions

Requesty's security features include built-in guardrails and compliance tools that protect your LLM applications without adding complexity.

Testing and Validation

Thorough testing prevents production issues:

  • Use sandbox environments for all testing

  • Implement automated integration tests

  • Perform load testing before major releases

  • Validate all configuration changes

Recent Trends in Gateway Management

The gateway landscape is evolving rapidly with several key trends:

Monthly Updates: Major vendors now release monthly updates, with only recent versions supported. This requires staying current with updates while ensuring stability.

Serverless Complexity: The rise of serverless architectures introduces new error patterns, particularly around response formatting and permissions.

Enhanced Security: Advanced fraud detection and security measures are becoming standard, requiring careful tuning to avoid blocking legitimate traffic.

Automation Focus: Automated monitoring and self-healing systems are becoming essential for maintaining reliable gateway operations.

For teams building with LLMs, Requesty's platform stays ahead of these trends by automatically handling updates, security, and optimization across 160+ models.

Practical Implementation Tips

For Payment Gateways

  • Always validate card information client-side first

  • Implement PCI compliance from the start

  • Use tokenization for recurring payments

  • Set up webhook handlers for async notifications

For API Gateways

  • Design with rate limits in mind

  • Implement proper API versioning

  • Use API keys with appropriate scoping

  • Monitor usage patterns for optimization

For LLM Gateways

  • Choose models based on task requirements

  • Implement caching for repeated queries

  • Use streaming for real-time responses

  • Monitor token usage and costs

Requesty's smart routing automatically handles model selection, while features like caching and streaming are built-in, saving up to 80% on costs.

Conclusion

Gateway integration errors are an inevitable part of modern application development, but they don't have to be a roadblock. By understanding common error patterns and implementing proper monitoring, error handling, and security practices, you can build resilient systems that gracefully handle failures.

For teams working with LLMs, the complexity of managing multiple model APIs adds another layer of potential errors. Requesty simplifies this by providing a unified gateway for 160+ models with built-in error handling, automatic failover, and intelligent routing. This means less time troubleshooting gateway errors and more time building amazing AI applications.

Whether you're dealing with payment gateways, API gateways, or LLM gateways, the key is to be proactive: monitor continuously, handle errors gracefully, and always have a backup plan. With the right tools and practices in place, gateway integration errors become manageable bumps rather than major roadblocks.

Ready to eliminate LLM gateway errors from your workflow? Get started with Requesty today and join 15,000+ developers who've simplified their AI infrastructure while saving up to 80% on costs.