# AWS Lambda Tips and Notes - Running a 0.5GB Lambda for a full month costs about $ 7-8 / month - Lambda CPU power scales up as you increase the memory of a lambda - JIT languages (Java, C#) can use compilation flags to reduce the cold-start times - Lambda functions can be invoked from CloudWatch action/events to create lambdas - Client Libraries need to be used to call other AWS services, including other Lambdas - Client Libraries might use constant or exponential retries, depending on the library used - Use Lambda Layers to use (large, many-MB-sized) libraries in your Lambda - Step Functions can be used to make multiple calls in parallel, but requires a **static** call graph - Note that SQS is a pull-based queue, so it cannot be itself be used as a buffer for rate limiting without adding a specialized/custom poller or Kinesis directly - Therefore, rate-limited lambdas/services should not be used as sinks for SQS and the native poller