# Relayer Overview

This section describes how OpenLaw executes and schedules recurring smart contract calls.

# Challenges

Many commercial relationships involve ongoing transfers of assets between parties. Blockchains are not natively capable of executing and scheduling the transfer of assets between parties. OpenLaw has built tooling that makes it possible to create recurring smart contract calls to model out and execute more complex commercial relationships.

# How It Works

As described in our Markup Language guide, using OpenLaw, you can embed and execute smart contract code running on the Ethereum blockchain. In order to do so, you need to create a smart contract call, which can be embedded in a template and executed when all of the relevant parties sign the agreement. An example smart contract call is included below.


#Smart Contract to Pay Employee
[[@Payment in Wei = Payment in Ether * 1000000000000000000]]

[[Pay Vendor:EthereumCall(
interface:[{"name":"makePayment", "type":"function","inputs":
[{"name":"RecipientAddress", "type":"address"},
{"type":"uint","name":"PaymentInWei"}],"outputs": []}];
arguments:Recipient Ethereum Address,Payment in Wei;
startDate:Payment Start Date;
endDate:Payment End Date;
repeatEvery:"1 minute")]]


The OpenLaw agreement calls the smart contract found at the following Ethereum address 0xe532d1d1147ab40d0a245283f4457c733b5e3d41 (opens new window), (currently on the Rinkeby testnet). The smart contract contains a function "makePayment."

As you'll see the smart contract call contains some other arguments, including "startDate," "endDate", and "repeatEvery." If these arguments are set, OpenLaw will package and execute the smart contract at the interval set in the "repeatEvery" argument.

# Frequency of repeatEvery Argument

The frequency can be set in seconds, minutes, hours, days, weeks, months, and years (e.g., 30 seconds, 1 minute, 5 hours, 7 days, 2 weeks, 6 months, 1 year). You can also mix time units when setting the frequency (e.g., 2 minutes 30 seconds, 1 week 3 days).

# Impact of the OpenLaw Relayer

Because many ongoing relationships involve the transfer of payments or assets over an extended period of time, the underlying smart contracts necessary to facilitate an underlying transfer of payments/assets can be simplified. This increases the range of commercial relationships capable of being coordinated and facilitated via a blockchain.