What Developers tools are?

Dapp development requires an understanding of the Web3 Javascript API, the JSON RPC API, and the Solidity programming language.


There are developer tools that help you develop, test, and deploy dapps in a way that automatically utilizes the resources listed below.

  • Web3 JavaScript API – This is the main JavaScript SDK to use when you want to interact with an Expanse node.

  • JSON RPC API – This is the low level JSON RPC 2.0 interface to interface with a node. This API is used by the Web3 JavaScript API.

  • Solidity Docs – Solidity is the Expanse developed Smart Contract language, which compiles to EVM (Expanse Virtual Machine) opcodes.

  • Test Networks – Test networks help developers develop and test Expanse code and network interactions without spending their own Expanse on the main network. Test network options are listed below.

  • Dapp development resources. This assists you in developing, debugging, and deploying Expanse applications.







Mix is the official Expanse IDE that allows developers to build and deploy contracts and decentralized applications on top of the Expanse blockchain. It includes a Solidity source code debugger. Mix


Below are developer frameworks and IDEs used for writing Expanse dapps.

  • Truffle – Truffle is a development environment, testing framework and asset pipeline for Expanse.

  • Dapple – Dapple is a tool for Solidity developers to help build and manage complex contract systems on Expanse-like blockchains.

  • Populus – Populus is a Smart Contract development framework written in python.

  • Eris-PM – The Eris Package Manager deploys and tests smart contract systems on private and public chains.

  • Embark – Embark is a Ðapp development framework written in JavaScript.


Commandline console for Expanse nodes.

Ethconsole connects to an Expanse node running in the background (tested with exp and gexp) via IPC and provides an interactive javascript console containing the web3 object with admin additions.

Here you could find a list of available commands expanse node control commands

To use this console you would need to start a local expanse node with ipc communication socket enabled (file gexp.ipc in data directory). By default ipc socket should be located at you local home directory in .expanse after you started a node. You could also set –test option to use specific node test commands.

In the console you could then type

Here the defenition of –test mode node commands:

More information about node configuration file.




Swarm is a distributed storage platform and content distribution service, a native base layer service of the Expanse web 3 stack. The primary objective of Swarm is to provide a sufficiently decentralized and redundant store of Expanse’s public record, in particular to store and distribute dapp code and data as well as block chain data. From an economic point of view, it allows participants to efficiently pool their storage and bandwidth resources in order to provide the aforementioned services to all participants.

From the end user’s perspective, Swarm is not that different from WWW, except that uploads are not to a specific server. The objective is to peer-to-peer storage and serving solution that is DDOS-resistant, zero-downtime, fault-tolerant and censorship-resistant as well as self-sustaining due to a built-in incentive system which uses peer to peer accounting and allows trading resources for payment. Swarm is designed to deeply integrate with the devp2p multiprotocol network layer of Expanse as well as with the Expanse blockchain for domain name resolution, service payments and content availability insurance.

ÐΞVcon talks on swarm

Code and status

Storage on and offchain


A marketplace that facilitates scheduling transactions to occur at a later time. Serves a similar role to things like crontab in unix, or setTimeout in javascript.


A marketplace that facilitates verifiable execution of computations off-chain. Allows for very expernsive computations to be used within the EVM without having to actually pay the high gas costs of executing them on-chain.




Random number * https://www.reddit.com/r/expanse/comments/49yld7/eli5_how_does_a_service_like_szabodice_grab_a/


The Expanse Virtual Machine (EVM) is the runtime environment for smart contracts in Expanse. It is not only sandboxed, but actually completely isolated, which means that code running inside the EVM has no access to network, filesystem, or other processes. Smart contracts even have limited access to other smart contracts.

Contracts live on the blockchain in an Expanse-specific binary format (EVM bytecode). However, contracts are typically written in an Expanse high level language, compiled into byte code using an EVM compiler, and finally uploaded on the blockchain using an Expanse client.

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