[Music]

All right. What's up? I'm Austin

Griffith. Uh, like Pascal said, I work

for the uh I work for Ethereum at the

EF. My goal here is teaching folks how

to build on Ethereum, and we're going to

speedrun through building with the best

tool out there, Scaffold. Uh if you want

to get started, there's lots of material

ethereum.org. It's a great resource.

If you if you have a uh a university, go

join us at uh ethereum on tour. It's

tour.ethereum.org.

Uh if you are a developer getting

started and you know how to build some

things, but you're like, "What do I

build?" You need to go build a whole

bunch of things. Go to

speedrunthereum.com

and get started building. If you uh want

to know, want to just build some things,

that's what you got to do. That's what

we're going to do here with Scaffold

ETH. So, here we go. We're going to get

started with Scaffold ETH uh right away.

You can ask questions in the chat. Let

me see if I can even find the chat. Oh,

yeah. I got it. I got it here. Here we

go. Feel free to drop questions in the

chat. I'm going to drop scaffold.io in

the chat. This is what we're going to

use. We're going to use a tool. We're

going to try to build something uh in 30

minutes here and uh hopefully deploy

something to production. So, uh let's

get started. So, Scaffold ETH uses MPX

create ETH latest. We're going to paste

that in and we're going to create uh I

don't know. Let's let's see what is

this. ETH online

2025.

Yeah, there we go. Let's let's create

this. So, uh here's your first kind of

choose your own adventure, right? You

have either hard hat or foundry. We we

use either one of these. Uh whichever

one you like the best. Um if you're

using either one of these, it's going to

be all the same commands within Scaffold

ETH. So you'll do yarn deploy and it

will deploy whether you're using hard

hat or you're using foundry. Um I think

a lot of the cracked engineers like to

use foundry because you're writing your

tests in solidity and it's a little bit

faster. Uh I think there's a lot of

older projects that are using hard hat

and also um it's I don't know maybe a

little friendlier for deploying. I don't

know some some people like to use hard

hat still. We have both. You'll find a

lot of things like this in the ecosystem

where there's multiple options and that

creates uh diversity and uh it works

great for a decentralized ecosystem. My

WETH node over here died the other day

and if we were only using just you know

Ethereum would have been in a lot of

trouble but thankfully we have GE and

other uh consensus and execution layer

clients and a strong diversity leads to

a stronger ecosystem. Okay, so scaffold

ETH starts out with this one command and

uh you CD into your build and you're

going to need to fire up a few things.

You'll run a chain which uh is Anvil or

the other one. Basically, you get a

local host uh blockchain and it has a

bunch of addresses that allow you to uh

you know send Ether around, do whatever

you want. It's just like a little copy

of Ethereum. And then you can yarn

deploy and that's going to deploy a uh

placeholder smart contract. And we'll

also need to start up a new window for

yarn start which is our front end. And

there we go. That's the whole setup.

That's how you get started. You have

your chain, you have your front end, and

then you can kind of deploy over here uh

in this terminal. And we'll come back

here and we'll deploy a bunch of things

uh in this terminal. But feel free to

ask questions in the chat if you're if

you're joining along. We're going to let

scaffold ETH load up here. And we're

going to use cursor today. We're we're

using a lot of AI, right? So, I'm going

to open up cursor. And that's going to

be over here. Let's see. How do I shrink

this? There we go. I'm going to shrink

this and put it over here. I don't know

if it's even useful. And scaffold comes

up. This is what scaffold looks like.

This is your front end. You've got um

burner wallets and a faucet. And you got

you have this debug contracts tab. And

this is where you'll probably spend a

lot of time at first. Uh hitting that.

Let me see if I can get some light here.

Let's go. Let's get some Which button is

it I'm hitting. Oh, there we go. Really

bright. Okay. So, uh let's see. We've

got our debug contracts page. This is

where we can poke at our smart contract

and scaffold the ETH foundry contracts.

Let's get in here and look at our

starter contract. So, scaffold comes

with a starter contract. Uh in this

case, it's kind of a greeter contract.

You can see here there's a set greeting

function and it updates some string

storage, right? And so if we go over

here and look at it, here is kind of our

interface where we can interact with

that contract. And we can see we could

set the greeting to hello world. So this

is going to fail. And when I hit this,

it's going to say, hey, you don't have

any gas. Oh yeah, I've got to go to the

faucet and grab some gas. Right? You'll

also notice that as I make this

transaction, there's no pop-ups for

chain ID or moving me over to the right

network or anything like that. Uh, we

don't have to sign any transactions

because we're going to use burner

wallets. When I hit send here, it just

makes the transaction. You'll notice

there's a nice little counter. Watch. I

can make that counter click, click,

click, click, click, and go. So, this is

really nice for testing when you're on

local host. You can just hit buttons and

interface with your smart contract. Poke

at it, get it to do the things you want

it to do. I always like to, let's see,

we've got this total counter here. I

always like to make a new function

called like count by three or something

like that. And no, not return three.

What we want it to do is do total

counter plus equals three. something

like that where every time you run this

function, it's going to increment your

total count by three. Uh, it's not

liking that. Let's let's ship it. See

what it says. If it doesn't deploy,

we'll we'll let uh AI fix it. So, let's

redeploy our contract.

And we're going to add a reset there to

make sure we force a new contract out

there. Oh, yeah. It's not letting me do

that. Uh oh, we don't want to return

anything. Needs to not be pure. There we

go. It just added some extra things in

there. That's why. Okay, here we go.

Let's redeploy our contract. So, this

lets you kind of tinker around. It lets

you quickly tinker with Solidity, deploy

a smart contract, and then interface

with that smart contract. We we can see

that old address, now we have a new

address. It kind of hot reloads, and now

we have this new count by three button,

right? And when I click that, there we

go. Our counter increments by threes for

some reason, right? Now you can imagine

we you know make this payable

and we maybe come up with some uh UN 256

public

price and set it to you know 0.001 001

ether. And then maybe we require that

they pay the price. And then maybe we do

something really cool where we say price

equals

price uh times 104

divided by 100. Right? You kind of have

to do this numerator denominator thing

because you can't use decimals. Uh EVM

doesn't do floatingoint math. You learn

all these things as you start tinkering

with solidity. But now we have some

count by three function that you have to

pay to use and there's some price and

that price will go up on a price curve.

Just kind of randomly tinkering with

solidity. We're playing around here. Now

we have to pay money, right? We have to

pay this much which also is 0.001 ether.

And you have to take that times 10 to

the 18. And you'll notice that as we hit

this uh our price goes up. If I try to

pay that again, it's going to fail. So,

we have to pay, you know, it it's going

up by 4% each time on a nice little

price curve. And we can see that price

going up. And also something interesting

is happening here. Our contract is

collecting money, right? There's money

loading up in this contract. You're

literally programming money. So, this is

uh how you get started with Scaffold

ETH. Go to scaffold.io, run that

command. You'll have to bring up your

local blockchain, your front end, and

then your yarn deploying all all you

want here with with any changes. You've

got burner wallets and smart contract uh

kind of hot reload adapting to your

contract. As you add new things, this

debug page changes. Then eventually you

move over to this kind of frontend area

here and you kind of edit out your front

end to talk to your smart contracts.

Maybe you're going to talk to an

existing smart contract. You add them

into like your external contracts in in

scaffold ETH and then you could maybe

like I don't know have something that

like puts money into unis swap or

something with a button push here. All

of that is good for tinkering and

getting started. Uh what I want to do

today I think the title of the talk is

the best tool I should show the docs

real quick. Um the best tool for

building apps on Ethereum uh is scaffold

ETH. It's great for building apps

quickly. There's a video here that

watches me. I think I build a whole app

in eight minutes. Very similar to what

I'm doing here. Um, if you want to

interact with your, we were talking

about external contracts, you could go

to the docs, right, and and find this.

Let's let's paste the docs into the chat

just so folks have it. Boom, there it

is. Uh, if you're interacting with your

smart contracts, though, you're going to

use these two important hooks. This is

the hook that you would use to read from

your contract. This is the hook you

would use to write to your contract. And

there's nice little examples here you

can copy paste into your code and get

started. So that's how you would do it

the manual way. Today we're talking

about uh the best tool for oneshotting

apps. So we're going to use uh Claude

and Cursor and we're going to try to uh

oneshot some kind of an app. Uh I've

been uh a lot of times on the tour. I

think I already shilled this, but let me

shill it one more time just because

we're shilling. On the tour, I do a lot

of uh where uh talks where we build a

voting app and we show how you can build

an app where people can vote and I show

a centralized example and then I rug the

simpleized example because it's uh it's

centralized. I can rug it and I can

change the vote and I can censor it. And

so then we build a a smart contract

version that you can't rug which is kind

of fun. Uh but uh let's build something

interesting here. I was thinking about

FOMO 3D. If anybody uh remembers FOMO

3D, it was this app that you would uh

you had to like keep pushing the button

and if you the last person to push the

button when the time ran out get paid

got paid all the money in the contract.

And that was such a funny uh mechanism.

It was basically a bounty to break the

the chain. I feel like we should try to

oneshot something like that. So uh

here's what we have. We have uh scaffold

ETH up. It has uh our smart contract

here, but there's also a cursor rules

file. So, it knows how to make the front

end. It knows how to make the back end.

Uh we're not gonna let's let's not even

mess with our contract at all. We're

going to start with like a complete

blank thing. No context, not talking to

anything, just the cursor rules. I'm

just going to try to oneshot into

scaffold eth and see if it builds it. I

don't know if it will. Let's see what

happens. Um, but let's build an app like

FOMO 3D

where there is a single big button and a

countdown.

So after it deploys, let's see,

the counter starts counting down.

for let's see from like five minutes or

something like that, right? Well, it's

not it's going to be hard. We're we're

going to hardly have any time to test

this if we put it out there, but uh

let's say 2 minutes.

Uh if it gets to the end, anyone can run

a function

that pays

all the money in the contract to the

last person who hit the button, right?

So,

uh, so when you click the button, this

is a terrible description.

I hope I can figure out. Click the

button. Uh, the time,

uh, adds two minutes and keeps track of

the last person to click the button.

Right? That's that's the whole smart

contract. The front end should just be a

button and a countdown.

Something like that. Let's see what

happens. We're using Claude and cursor

here. Uh let's see if it's able to write

our smart contract. Yes, FOMO 3D. So,

this is FOMO 3D in 2025. Uh you know, we

don't have millions of hours spent

pouring over the Solidity, making sure

it's perfect. We probably should and AI

may not be at the point where you should

be writing smart contracts with it yet,

but I think uh we're going to try it

today. Maybe it will have a giant bug in

it. Uh if we have time, I'll put it out

on a public network just to tinker with

it, but let's see where we go. Okay, so

it looks like it's already writing a

contract for us. Let's go look at it and

see how it looks. There is Yeah, so

there's the last clicker. There's the

time increase. There's the how much it

costs. That's kind of expensive. Maybe

we should make it a little cheaper. Uh

let's see. So, uh when we deploy it, it

will have it will start at 2 minutes.

When you click the button, it's going to

probably add the time increase to to the

game end time.

We're keeping track of total clicks for

some reason. That's going to cost money.

We probably should put this on an L2,

not uh Ethereum mainet.

Uh and then you get to claim your prize.

There's time remaining. Get pot size.

Let's look at claim prize. Let's look at

the require statements, right? We're

making sure the game hasn't ended yet.

We're making sure it's after the time.

The last clicker isn't the zero address.

Then it sets it to true.

Gets the prize money. How does it send

it? I get out of here. And does this,

right? I think you could grief this by

having uh this be a smart contract with

uh a

a receive function that does some extra

execution. So there's a lot of ways to

grief this. But here we go. It looks

like it made FOMO 3D for us. And when we

click, hopefully we see this time uh go

forward. I don't see the time counting.

Let's see what's going on here.

Okay, I feel like the timer is not

working quite right. Maybe it's still

working on something.

Cuz as we click this, the time should

click up by Oh, wait. We need to deploy

our contract. Yeah, yeah, yeah. Let's

Let's deploy. Oh, not reset one.

Uh, compiling. Compiling. No changes

found. Let's yarn deploy reset. Let's

make sure we get our contract deployed.

All right. And then we could go look at

it in the debug contract page. It's

still loading our front end up here. We

got to wait for this to come in and

we'll see if we made FOMO 3D. Yeah,

there we go. So, that's the whole thing.

There's just a clickable thing. You pay

some cost. Let's actually lower that

cost, right? Let's put it to 0.001.

Uh, which is still

what is that like 40 cents? Something

like that. Let's Let's go with that.

Let's go with that. Let's yarn deploy

the new contract. Make sure we get a new

contract here.

Make sure the price goes up a little

bit. Or goes down a little bit. There we

go. Okay. Here we go. Let's look at it.

So, here is everything. If I click this,

I don't see the price going or the time

going up. So, you may So, we didn't

oneshot it. We failed. We failed the

oneshot uh thing here. Uh let's see the

timer.

Wait, wait, wait. Let's go check and see

if there's a time remaining.

Let's let's add that in, right? Uh

should be a time remaining

function that tells Well, yeah, it knows

what that is.

and the front end. If I click the button

three times.

Let's see if that works. Because what

should happen when you click the button

is it should increase the time. Ah, see.

Yeah, there's not. It should actually be

game ends plus it should be this right

here. Oh, no, not that. It should be

game end time plus time increase.

Not. Yeah. Yeah. Hold on.

Yeah, this is a fail on the oneshot. I

think maybe I didn't explain it very

good very well, but let's see. We want

it to be something like this where it's

not the end. It actually like increases

the time way out. If someone clicks it

three times, it should increase the time

way out. But maybe not. Maybe that's not

even how FOMO 3D works either.

Let's just see. Let's see what it does

here. Terrible oneshot. Okay, we got we

have 10 minutes left though. We need to

put this out into production so we can

play with it. Uh just showing that it

doesn't take long here. You're you're

kind of prompting your uh you know

nudging it along. Sometimes if it

doesn't one-shot it perfectly. Uh let's

make sure it's still doing some frontend

stuff. I don't want it to deploy. I want

to do the deployment myself over here.

Let's see. Let's make sure we get a new

contract here. Uh oh. Uh oh. What was

that?

Oh. Oh, this guy was doing a deployment

at the same time I was doing a

deployment. So, we got some nons errors

there. There we go. Okay. Fresh

contract. There we go. Looks good. Uh,

time is counting down. Oh, weird. Look

at that. If I hit reload, it always

restarts to There's There's definitely a

front-end bug. Really? Oh, wait, wait,

wait. I mean, that looks good. Three

minutes and 40. Okay, no, it's actually

working.

>> If I wait a little bit and hit reload,

I'm getting a fresh number. If I click

this, it's going up. Okay, so now we

need to test real quick if like we can

get the money out of it when uh the time

Let's just set it at 0.1.

Uh, is there a button to get the money

out

when the time runs out?

So, as you're building things, you're

programming money, you need to think a

lot about incentives. We could set this

up. So, I mean, the person who gets the

money is going to be incentivized to

push the button, but whatever you build,

whenever you need an automated

mechanism, you need to be thinking about

incentives and build those incentives

into your smart contract. So someone out

there, whoever can click the button to

roll your logs or uh you know increment

your system, move it into a different

state, but they have to be uh

incentivized to do so. And you have to

be thinking about incentives as you're

programming these mechanisms. Okay, here

we go. Uh let's see. I turned it down to

one minute. And let's deploy a fresh

one. And let's actually we should do

like 30 seconds. Let's let's do like 20

seconds. We don't have time here. Let's

deploy another one where it will start

with 20 seconds. I'll click the button.

It'll put it out to 40 seconds. Uh the

money will be locked in there and then

hopefully it will run out of time and

we'll be able to sweep the money out and

prove that it works. All Oh yeah, there

is a nice claim prize button there. Very

nice. It kind of flashes. That's pretty

ugly. If we were building this forever,

we would want to make that look nicer.

Okay.

There we go. So now we just have to sit

here and wait for 30 seconds. Let's get

started on the deployment. If we're

going to put this out on a live network,

we probably need to Let's just do

deploy-

Oh, actually, wait, wait, wait, wait. Do

we still have those console logs in

there? We don't want console logs. Uh

yeah, yeah, yeah, yeah. We want to pull

this out. We don't we don't want any

console logs. Uh this stuff, right?

We don't want to put console logs out on

mainet. That's just a bunch of trash put

on mainet. Let's make sure this still

Oh, no, no, no. Let's I don't want to do

that yet. There we go. Let's claim the

prize. Make sure this works. So, there's

0.01 in the contract. If we go look at

the debug contracts page, we see that

there's like 41 cents in there. Uh, if I

hit claim prize, oh no, it says game

still active. That's not good.

Uh, why is that? Let's see. The claim

prize

game still active. So the block

timestamp has to be greater than the

game end time.

Oh no, did I redeploy? What happened

there?

This is the worst worst oneshot in

history that usually you can just like

prompt the thing and it will build like

I do always do this with a voting app.

I've done even more complex apps than

this. I don't know why. Let's make sure.

Am I using the right model? I'm usually

using cloud 4.5 sonnet. is pretty good.

Uh something happened here though where

it thinks that the game was still going.

It's worth the extra 40 seconds to make

sure we don't put just junk out on

mainet. Uh okay. So it's that 30

seconds. If we look at the game

timestamp. So whatever this time stamp

is needs to be

less. Yeah. Hopefully we don't get game

still active here. Let's see what

happens. We might though. There might be

a bug in this code. Uh, I guess we'll

find out in just a second. Wait for this

to countdown. Wait, why is it 30

seconds? Uh,

I feel like the timer is not working.

Oh man. Let's see. Uh, and if I try to

claim the prize, it's going to say game

still active. I may need the console log

so I can figure out what's going on

here. What's wrong? Uh, I feel like

Let's go look at the code real quick.

Let's Maybe we have to do something

manually here. block timestamp

game end.

It starts at

time stamp plus increase. That's I mean

that's pretty good. That's what we want.

I feel like the front end is just

failing here. This guy here. There's

something wrong here. If I hit reload,

it's going to go back to 30 seconds.

Yeah. Uh yeah.

Oh. Oh, you know what? I know what this

is. Okay, we're on local host and

there's no transactions happening on

local host. So if I make a transaction

here, it's going to notice that the time

has passed. That's the whole problem.

Okay. Now, if I reload, it's at zero.

Okay. So there's no transactions

triggering on our local network. And so

the time stamp is always whatever the

last transaction we made. So this works.

Okay. We're good. We're ready to go.

Let's go to production. We only have

five minutes left. So what we want to do

is deploy to uh some network. I would

say which whoever let's go look at

whoever is at the top of L2 beats right

now. Uh, it was Arbitum last time I

checked. They're there. I usually go to

Arbitum or base, but let's deploy deploy

to arbitrum. Uh, let's see. Arbitum, I

think. Let's just use this dude here.

So, normally it's going to create a key

store, a key pair, and you have to put

some money into it. I think I just have

created one recently. Let's see if it

has any money left in it. If not, we may

need to load up some money.

Yep. Okay, it doesn't have any money.

Okay, let's yarn generate one then real

quick. We're going to create a generator

account. Uh we're going to generate our

own account. We're going to call this aa

uh we're going to put in a super uh

secure password. Now, if I do yarn

account,

I will get that account back and we'll

say number two there and I'll put in my

super secure password. Okay. And now we

have some money. Now we need to send

some arbitum ETH into this dude, right?

Let's open up my wallet here and let's

hit send and let's send to this dude's

address. And we want to send some

arbitum ETH, but not very much. That

should be enough. Hopefully 41 cents is

enough to deploy this smart contract.

All right, there we go. Now let's yarn

deploy

to arbitrub and let's see if our uh

let's see number two there with our

super secure password.

Please work second try.

Here we go. We're deploying our contract

live to arbitum. Wow. It can't be more

than

41 cents, can it? How much does it cost

to deploy on arbitrum?

Uh,

maybe I didn't send. I did.

Uh,

$4. No way. No way, dude.

I have no idea. Maybe there's a gas bike

right now and it costs a lot more than I

think to deploy to arbitro.

Uh, let's do a yarn account

and pick our account. And so, it's

number two there with that password.

Now, does it have some arbitrum? Yeah,

it's got plenty. Okay, let's try one

more time. Yarn deploy network arbitrum.

Select number two there.

Enter our terrible password. Please work

fourth try.

There we go. There we go. Okay, our

contract is deployed. Now, we'll need to

go to the scaffold config and we'll need

to tell it that we deployed to So, we're

not on Foundry anymore. We're on

arbitrum.

And there we go. Now our whole app is

going to reload now and it'll be on

arbitum. Actually, it's going to be so

quick I won't even be able to get the

Yeah, it's already out. Okay. So, we

need to redeploy again, but we need to

change our time back to two minutes,

right? Or maybe

we don't have time. Okay, I'm going to

I'm going to set it to five minutes. So,

uh, you pay 41 cents and it goes 5

minutes and then if you let it end,

you'll get the money back. Let's let's

deploy one more time. Hopefully this

works. We got number two there.

Super secure password. Okay. And then

hopefully

we get our contract. There we go. This

should reload.

Awesome. Okay. Okay. Then if I do yarn

IPFS,

we're going to put this front end out on

IPFS and I'll be able to copy and paste

the address into the chat and then y'all

can go to this funny website and click

this button here. Connect your wallet.

I'm going to put my first 41 cents in

here and Oh, wrong network. Bumps us

over. Click here.

All right, I'm going to put 41 cents in

and it should take the time out to Oh

no, our front end died because I'm

deploying the IPFS stuff. All right.

Oh no, build error in IPFS. Let's see.

Is this up? Let's bring this back. I may

have to push it to Verscell. It's way

cooler when you can deploy the app to

IPFS. But maybe because I'm trying to do

two things at once here, it's not

liking.

page block explorer.

Yeah. Okay. Let's go. Let's go hit the

thing. I think this is the end of the

demo. The oneshot was barely successful.

We were able to create a FOMO 3D like

app on Arbitum Live uh with not a single

prompt and one step. It looks like that

transaction did go through. Uh you can

click this and it's going to push things

forward five minutes. Uh

and once this time runs out, uh whoever

was the last person to pick it, which is

the current winner here, can come

withdraw their funds. Let's try one more

time to see if I can get this to push to

IPFS. If not, I'll have to yarn versel

and it will take a much slower time

getting uh to versel and I can paste the

uh the app out to my Twitter or

something like that. Do you need API?

You do not need an API key to deploy to

IPFS. It's actually using uh BG IPFS

which is our own uh panning service

uh right here. Yeah. So, BGIPFS is

what's used under the hood for scaffold

ETH. And uh let's see. Did our Oh, wait.

Oh, wait. I'm going to have it. It's

going. I think it was because I was

doing too many things at once there. I

was running my front end and I There we

go. There we go. Our page is live. All

right. I'm pasting it into the chat.

Someone Someone else go push the button.

You have to pay 41 cents and you're

definitely going to lose your money.

This is a terrible, terrible, terrible

app. But, uh, this is just an example of

how you can quickly build a money Lego

on Ethereum or an Ethereum L2. Uh, here

we go. I'm going to click the button one

more time. Pay another 41 cents. Uh,

here we go. And it will, you definitely

don't want to click the button when

you're already the current winner. And

it's just going to push the time back

more. So, now it's 17 minutes. sometime

17 minutes from now if no one else has

clicked this. I'll be able to get in

here and get my money out. But also, you

can uh you can go click the button too

if you want at this address. Let me let

me put it into ETH. Oh, whoa. Get out of

here. Let me put it into ETH build and I

can have a QR code so then anybody can

scan this. Let's go to ETH.Uld.

Let's go to build. I'm going to get a QR

code for the website so you can get this

long uh link out.

There we go. Okay, there's a QR code.

There's also uh that's that there's no

money in that. That's the thing where

you can just click it and it generates

them. Uh but check out that QR code. If

you want to go play my crappy FOMO 3D

clone that I built with almost a oneshot

with Claude and Cursor and Scaffold

Eath, you can just scan this QR code

here and uh wait for the time to get

down toward the end and then click the

button and then if it waits five minutes

and no one else clicks it, you can claim

the money and win 40 cents or something

there. Cool. There's the app. It's at 15

minutes now. Thank you. Uh thank you for

playing. Go use scaffoldeth at

scaffoldeth.io

and uh build something cool. Thank you.

[Music]