Development of a Java-SDK

The JS SDK supports state channels

For the unit conversion, there are no specific guidelines afaik.

AE supports Java sdk? Where can I find it?

are you sure that the JS SDK supports state channels? haven’t found the respective code in the repo :sweat_smile:

yes, Æternity has a (community developed) Java-SDK. we are actively developing it here:

you can follow the progress of new features here:

if you want to have access to new features in our dev-branch which aren’t released yet you can always use the most recent SNAPSHOT version :slight_smile:


Thank you for sharing. Thank you for working hard for the prosperity of the AE community.

@marc0olo super sure! The integration tests are here

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we’re currently working on the fee calculation in our JavaSDK, according to the MINERVA hardfork upcoming. Is there any possibility to activate the new fee calculation adaptions to our local test chain?
Additionally, do some example transactions with the new fee calculation exist for validating?
Thanks and greets,

ok I talked about that with Dimitar on telegram. so in our case (running default settings with network ae_devnet) the new fee structure automatically starts on block height 1.

it’s all fine.

I also talked with him about the best way to implement a calculation for the minimum required fees and came to the following process:

  • create and serialize the tx without adding a fee
  • then calculate fee based on the specification
  • create a new tx with the calculated fee (plus some fix amount assumed to be needed on top because bytesize of new serialized tx is bigger)

if anybody has a better approach. please tell us :slight_smile:

Yes that’s the way to go!
It can be a bit confusing because sometime the docs are not very accurate, here is how the calculation is done in python:

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Also don’t forget you can use the goggles app to verify the fee.

thank you! :slight_smile:

you should consider providing an endpoint for googles where people can check validity through api calls :wink: … I think it would be great to have such an endpoint in the core of aeternity if thats not too expensive

That is a very good idea, but I am afraid that it will be misused and taken as a service provided for transaction verification, and I am not sure about that.

I also thought about that. So maybe it should only be active in debug-mode. I posted this question in the public developer hangout thread :slight_smile:

we managed to calculate the minimum fees according to your solution, but we found an issue concerning the documentation
it says, the gas price multiplier is 1000000 (
which is not sufficient
according to the python implementation, we choose 1000000000, which worked well
@noandrea - do you have an idea where this gap might come from?
Thanks and regards :slight_smile:

yes, the 1M is the minimum gas price set at governance level (it can never be lower than that since it is part of the consensus), while 1Bn is the minimum configured value set for miners, and it can be changed.

So if you set 1M as minimum gas price you are correct on a governance level but it will be included only if the miner has changed the default value for gas price to 1M. Therefore I suggest you to put the base value to 1Bn but leave it configurable for the future.


@noandrea - thanks for the clarification, we will keep it configurable

Today we published a new release v1.1.0 that allows creation/recovery of HD wallets as well as automated fee calculation for transactions:


Hi @marc0olo, @peter-nexpur is building an integration for Generalbytes ATM and he is using your Java SDK.

Are you by any change in and could give him a hand and some feedback?

Best regards

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currently I am not in the devchat. I tried to join with my github-account but I always get an error message User is not activated. do I need to register normally?

of course we can help and give feedback :slight_smile:

I’m sorry for that, what is your (registered) name or part of your e-mail i’ll get you in.

Edit: found it and you are activated now and can login.
Edit2: welcome to the aeternity Developers Chat :slight_smile:

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