Is there an upper size limit for a text variable in a flow? We are told there's a 4000 character limit for input variables, but I want to know about ordinary variables that are not being used for input or output.

I believe that Apex imposes no limit other than heap size (6MB) on string variables. Are flows relying on Apex strings?

I have a test flow where I have demonstrated that flow text variables can hold at least 8k. I can continue adjusting the test to get some idea of what the limit might be in practice, but I'm interesting in knowing if there are any published limits. I have not found any thus far.

1 Answer 1


The max size for a flow is apparently 4,194,304 characters. Once I got rid of that error, I found that the UI really doesn't like strings over about 1,000,000 characters for a default value. I finally found the maximum size for a default value, which is a paltry 65,535 characters, after which you get:

Text: data value too large: "my beautifully long string... (max length=65535)

I ran a doubler algorithm and found out that at 128MB of data, I would get an internal server error. It did get up to 64MB of data without crashing though...

So, it doesn't appear there's a programmed limit, but there is a hard limit before things break.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.