— User Guide to Start Using Smart Contracts 1/3

Here is a user guide of smart contracts for Home Browser. We introduce here how to connect with MetaMask, and create new contracts by using Home Browser’s current interactive markets view from its map. Finally, you see how to edit states of contract and close it away from market when no more use for it exists.

Table of Content

• Intall MetaMask
  • Connecting 1st time to wallet
• The sandbox & real deals
• Loading in new toy cash & coins
  • Finding some fresh ETHs
  • Swapping to USDC / … / DAI stablecoins
• Creating new real estate contracts fast
• Editing all states of contract
  • Closing contract, requesting refund & new owner
  • Changing prices
    • Deal’s price
    • Home’s bid / ask price
  • Contract’s deadline
• Buying existing contract’s deal
• Final agreements by seller and buyer

During this user guide we are going to work & finish ready a public smart contract for RE private showings as an example from the real market’s situation as it was during publish of this text. So, this is hands-on demo how buyer & seller meets each other virtually using their crypto wallets for the deal.

INSTALL METAMASK

To use this guide right away just get MetaMask’s secure Ethereum wallet to yourself (https://metamask.io) on laptop. There are extensions for Chrome and Firefox browsers existing today. Just follow the wallet’s guides and create new accounts with it after that.

Connecting 1st time to wallet

When you open any page of Home Browser that uses smart contract very 1st time the things are little different.

MetaMask’s wallet will ask you permissions to connect with the web page once. This is happening normally so that MetaMask will give you the list of your all accounts so that you can agree which accounts you want to use with the whole web site.

IMPORTANT: be sure to accept 1st connection of wallet only to our domains tere-tech.eu or tere-tech.com !

Next times when you come to Home Browser’s page and start to use smart contracts MetaMask let you just Unlock and asks password for the wallet.

The sandbox & real deals

It is a very good idea to test smart contracts with no real risk of capital and that is possible to do with Home Browser too on the following way.

Home browser supports Ropsten, Goerli, Mumbai Test Networks (… at least …) as a sandbox so that you can get used to smart contracts with no risk of real ETH units in transactions.

When you are ready you just switch to Etherium mainnet and then activate your real money on MetaMask’s wallet by one click. All things work just similar but now the ETH flows in real network of Ethereum.

Loading in some toy cash & coins

Since you need to have some ETHs in wallet before anything can happen with smart contracts here are a few tips how to receive the first toy funds for testing purposes only. You should select Ropsten test network at first in use with your crypto wallet & copy its current account address ready.

Finding some fresh ETHs

• You can ask totally free ETHs from many Ropsten’s ”faucets” very easily:
  • https://faucet.egorfine.com/
  • https://faucet.metamask.io/
  • https://faucet.ropsten.be/

Swapping to USDC / DAI / other… stablecoins

When you have get some ETH’s from faucet the most easiest way is to swap some of them into your wished stablecoins. There are many swapping sites to use with different competing exchange rates but since this is now just ”toy coin” you can go fast to next link and in no time to exchange some ETH native crypto into USDC or DAI. This service also supports Goerli’s test network.

• https://app.uniswap.org/

Nice bonus is that it suggests automatic addition of your converted stablecoins into MetaMask’s wallet: that is often one painful extra step for beginners.

When you have ETH’s and little bit of stablecoins on wallet you are ready to go ahead here 🙂

Getting those real cryptos & stablecoins

When you move from training mode to the real thing a good way to get some real ETHs is to join in some main crypto exchanges (eq Coinbase, Binance, ec…) for that goal.

There you can buy at the best price all needed ETHs, preferred stablecoins, and Matic when converting them from fiat euros.

After getting them on exchanges client’s account just withdrawing them to your own MetaMask wallet is usually just one easy step at the end.

Note: withdrawing costs can be very different from exchange to exchange and it is a good idea to check them out before becoming customer.

Creating new real estate contracts fast

When you open Home Browser as logged in user (eq home’s seller/buyer, developer or investor levels) you can find the current market’s situation for each quarter of Tallinn at once.

Every cubicle’s icon here on the map means one home’s current active sale and by opening it you will find also another button for creating new deal at the bottom of that bubble.

By selecting this you will start simple 1-step dialog window that is helping for building data of new contract on blockchain.

All details of popup window must be filled before you can go ahead and let the Home Browser then create new smart contract for you on fast & easy way.

Most important things are: your role, the prices (service fee + home’s offer), unit of stablecoins in use, and the selected deal’s service type. When you publish open contract on blockchain here and somebody accepts it you need to deliver just what promised. Otherwise, you take a risk of expiring contract over its deadline as active contract keep on going open & locked until both agree it by wallets. Some suggestions prices are put in automatically for you.

Home’s ask/bid field is automatic estimation for objective fair price to flat based on current market’s conditions and our ad-hoc smart BI rules. Its figure based on similarities of sales around your selected home and some past history of executed prices on the area.

After accepting this form by its button MetaMask pops up again to verify that you accept to spend estimated max costs of gas (= in ETH / Matic, etc) to create new contract on selected network of blockchain. This is the most expensive gas cost with our contracts always.

When contract is successfully created it is the time to fund it with your chosen service fee and MetaMask pops up once again to confirm the transfer of those stablecoins into new contract. This is much cheaper to do in gas than printing of new contract.

Next, interaction continues automatically and normally leads to new funded contract on blockchain after some delay of Ethereum’s network when you just need to wait & wait … just another moment.

Finally, Home Browser shows that all is ready (2 steps) and suggest to go look at your deal’s management & advertising page that was created automatically too.

NOTE HERE: when creating the very 1st time smart contract you need to allow pop up windows with the browser for our website.

See it yourself: this contract is very permanently there on test network, & find all its new transactions that happen in public out there. Seeing is believing 🙂

Now, you have them both out there: own monitoring/AD page on Home Browser’s site + its linked smart contract on blockchain that is storing your real funds in a very secure way.

New smart contract belongs only to your own MetaMask’s wallet when new deal was created and nobody else can control it.

TIP: It is very good practice to use the same account for selling / buying of these smart contracts at the beginning when just training how everything works with MetaMask’s wallet & try keep amount of accounts & tokens minimum other ways too. It takes some time to get used to how all is working at first and you must follow the famous ”KISS” -principle to prevent any bigger mistakes. Practicing by toy tokens can not make any damage to your real deposits – just do it.

CONGRATULATIONS ! You just did print & publish your 1st new smart contract in a few minutes !

Editing all states of contract

Contract’s own info page is the tool that let to follow what is going on with each already existing contract on blockchain and edit its behavior being its owner.

That is how you can also change the state of contracts nicely when you are a part of deal. By navigating to the bottom of monitoring web page you can find buttons that are available based on current situation of deal & your wallet’s account.

Normally, you can sleep, abort, change owner, and also sign final agreements of existing contracts there.

Be extra careful when cancelling any of your contracts because that leads to refund of deposits but also destroys the existing contracts all actions for the future at the same time permanently.

Closing contract, requesting refunds & new owner

There are three options to close running contract: taking it out for a moment, cancel it permanently or move to new owner. All of these works only when the contract is still unsold on market.

Closing the deal away by its button uses MetaMask so that the wallet sets contract in sleeping state & away from public use. All of its stored data & funds stay unchanged. Later, you can come back to same contract and wake it up back again. This is good option to you when something happens with the sale’s process that is not finally ending the efforts yet surely.

The cancel button is sending the request to blockchain to refund your contract permanently and close all of its operations from future’s use.

So, cancelling is best to use very carefully when the sale is really over for that property permanently and there is no need for the smart contract.

Moving smart contract is easy way to recycle cheaply working contract to new person without risk of loosing own funds. When this starts there is only on question: receiving new account of wallet presented. After that all goes smoothly by MetaMask into the blockchain and new owner can continue with its contract’s sale.

These two important things happen automatically before new owner gets contract in another wallet’s account:

• All its stored funds return back to your original wallet and contract’s balance becomes zero.
• Smart contract is closed to sleeping state on blockchain when changing its ownership. So, new owner has chance to set new service fee + check other changeable fields of contract before publishing it again.

NOTE: new owner needs to be customer of Home Browser in order to manage contract’s states & stored funds properly.

Typically, the recycling of contract happens naturally between two brokers when they want to change sale’s assignments with each other. This is very cheap & economical solution. It keeps running old smart contracts as long as needed from broker to broker on blockchain when that sale of home still continues. There is no limit how many times existing contract can recycle on this way !

Changing prices

Every existing contract has its service fee set for selected service type, home’s bid/ask price, and ending deadline. These can be updated flexible ways until contract is sold to any buyer & becomes locked. This action is only possible for unique owner of each contract.

Deal’s price

The price of service can go up and down just the way contract’s owner hopes. There is a little tiny pen symbol next to deal’s price on the page that opens popup window for this update.

Normally, this operation goes very smoothly via MetaMask’s wallet to the blockchain and leads to permanent update of funds in smart contract which then shows in wallet’s account in real-time.

The balance of wallet goes down when the owner of contract asks higher price of service when funds are sent to network. Opposite happens when the owner makes the service cheaper and the funds are flowing back to wallet.

Important to know here:

• Special case is when the owner set service fee zero eq asks all deposits back to own wallet: smart contract shuts down the contract into the sleeping state automatically. It just thinks that promising any service for nothing is not a good business !
• When trying to increase service fee bigger than there is available balance left on wallet’s account leads to fast error: this request is cancelled & not spending any ETH (/ other gas’s units) for gas. There is no chance to fund contract more than you have.

Home’s bid / ask price

Home’s bid / ask price can change freely starting from 10 € minimum up & higher. These updates of sale are stored permanently on the blockchain and they become locked when the contract is sold out. Let’s be careful what to promise here !

Contract’s deadline

Setting new deadline & ending time creates the owner nice choice to extend existing deal on blockchain as long as is needed with the minimum amount of payments. This is very good solution together with sleeping mode together: once created sale’s contract can live as lons as needed by switching ON/OFF for clients + change its running period flexible ways depending on how sale is going on.

Every sale’s contract is unique story of different events on blockchain and when you extend its period all other details remain untouched.

Normally, the owner of contract can expect to see around 10X cheaper updating cost when just extending (/decreasing) deadline compared to that to the cost of creating same smart contract from the start. Typically, setting of new deadline costs around 0.2 – 1 € / update depending on network’s load & traffic at that moment.

Buying existing contract’s deal

Buying any existing open deal & lock it yourself is easy when you have received its direct URL link to Home Browser’s public page somehow. Also, you need to be logged in as a basic user at least.

Here you have two options to do:

1. You can get the link directly from home’s seller (email, SMS, social media etc):
2. You will find the icon of interesting contract from Home Browser’s active sale’s map view

Every icon has clickable bubble that tells you main points of deal and let you go to its linked contract’s page fast too.

After you have clicked contract’s page open on the browser you can find the buying button at the bottom of page after checking carefully all details before that.

By accepting this MetaMask checks that you have enough balance in account to pay contract’s including service fee and comes then to verify the full transaction.

When you confirm window, service fee (using a small fee of gas in ETH) starts to move into the contract directly from wallet. After a while this transaction is then confirmed and permanently recorded in blockchain. The deal becomes locked between you and seller at once.

CONGRATULATIONS ! you have just bought 1st deal by paying it from own crypto wallet !

Final agreements by seller and buyer

When seller and buyer meet physically and agree about terms together for the property both need to sign the agreement ready once again from very same accounts of Metamask’s accounts that were used at first.

Contract’s buying did lead to the status where no other wallets (+ accounts) can go ahead with it. Only those two persons being part of deal can do that with their own wallets.

Accepting button is there for ending real deal and it is visible on deal’s page at the bottom.

Pressing that leads to this: MetaMask is sending just signature of accept (= 0 stablecoins / any funds sent out) from wallet(s)…

By doing with both wallets (contract’s seller & buyer) of the deal leads to end contract & sharing back all its deposits by the shares where seller (/broker) of home receives always that bigger part and home buyer smaller as it is told exactly in our previous text over here. Now when anybody opens this public contract they can find it did end normally before deadline.

Note: here in a short example we decreased in purpose the balance of contract down to 5 USDC before buyer’s act so that that the sharing of 1/3 between them was even more clear from total of 10 USDC.

The only exception for this outcome is when the deal is expired over its deadline already when the rules are more tight and one party has to admit doing something not so right.

Here are public hands-on links for this introduction:

• Smart contract’s details & demo page for private showings of home service
• Etherscan’s transactions on Ropsten’s testnet

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