Invokes a Lambda function. You can invoke a function synchronously (and wait for the response), or
asynchronously. To invoke a function asynchronously, set
For synchronous invocation, details about the function response, including errors, are included in the response body and headers. For either invocation type, you can find more information in the execution log and trace.
When an error occurs, your function may be invoked multiple times. Retry behavior varies by error type, client, event source, and invocation type. For example, if you invoke a function asynchronously and it returns an error, Lambda executes the function up to two more times. For more information, see Error handling and automatic retries in Lambda.
For asynchronous invocation, Lambda adds events to a queue before sending them to your function. If your function does not have enough capacity to keep up with the queue, events may be lost. Occasionally, your function may receive the same event multiple times, even if no error occurs. To retain events that were not processed, configure your function with a dead-letter queue.
The status code in the API response doesn't reflect function errors. Error codes are reserved for errors that
prevent your function from executing, such as permissions errors, quota errors, or issues with your function's code and
configuration. For example, Lambda returns
TooManyRequestsException if running the
function would cause you to exceed a concurrency limit at either the account level
ConcurrentInvocationLimitExceeded) or function level
For functions with a long timeout, your client might disconnect during synchronous invocation while it waits for a response. Configure your HTTP client, SDK, firewall, proxy, or operating system to allow for long connections with timeout or keep-alive settings.