Application Load Balancer payload limit?


Hello, I was curious what the maximum payload ammount is for an application load balancer? For example, what is the size limit that an ALB will allow a json request body to be for an HTTP post call. Is 100MB the limit?

i've checked for quotas but I'm not seeing payload listed.

3 Answers

Amazon Web Services (AWS) maximum payload to API gateway is 10 MB and maximum payload for Lambda is 6 MB and payload size for lambda behind ALB is 1MB, which cannot be increased. This includes both the request and response payloads. This limit includes headers, cookies, query strings, and any other data within the HTTP request or response. The following size limits for Application Load Balancers are hard limits that cannot be changed:

  • Request line: 16 K
  • Single header: 16 K
  • Entire response header: 32 K
  • Entire request header: 64 K

There's no inherent size limitation to the overall JSON request itself. The size limit for a JSON request body in an HTTP POST call can vary depending on several factors, including the web server, client libraries, and any intermediary components (like proxies or load balancers) involved in the communication. There is no fixed or standard size limit defined by the HTTP protocol itself.


answered 9 months ago

The max payload that ALB can handle will be a function of sum(request size + response size) x number of requests per minute. Higher the payload size lesser will be your number of requests that ALB can handle. There are more factors involved like HTTP vs HTTPS and also, whether backend connections are persistent or not. It will be best to open a support case and get ELB/ALB team to give a concrete answer.

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answered 2 years ago
  • Is there documentation where more info on this is available? In general this approach is a bit vague and makes it difficult to troubleshoot errors that may or may not be the result of a request payload that's too large.


In general, ALB will return an error when limits are exceeded. In the documentation there are limits on header sizes but I don't see any limit there on payload size.

What size of data are you trying to transfer?

profile pictureAWS
answered 9 months ago

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