Nothing’s more frustrating than setting up an API Gateway, only to get hit with a 403 Forbidden error. I’ve been there too.
Here’s how I troubleshoot it:
1️⃣ Check Resource Policies
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Go to API Gateway → Permissions
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Ensure the resource policy allows access to the intended users or services.
2️⃣ Verify IAM Roles & Policies
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Go to IAM → Policies
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Confirm that the IAM role associated with the API has the correct permissions to invoke the resource.
3️⃣ Check Lambda Execution Role (If Using Lambda)
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Go to IAM → Roles → Your Lambda Execution Role
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Ensure it has
lambda:InvokeFunctionpermissions for the API to trigger the function.
4️⃣ Review CloudWatch Logs
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Go to CloudWatch → Log Groups → API Gateway Logs
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Look for detailed error messages that indicate why the request is failing.
5️⃣ Inspect AWS WAF Rules (If Applicable)
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Go to AWS WAF → Web ACLs
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Check if any rules are blocking requests to your API.
Note: Always check CloudTrail logs to track any changes that might have impacted API access.
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