That is, how to snipe all the rares without using ERC721R!

Introduction: Blessed and Lucky 

Mphers was the first mfers derivative, and as a Phunks derivative, I wanted one.

I wanted an alien. And there are only 8 in the 6,969 collection. I got one!

In case it wasn't clear from the tweet, I meant that I was lucky to have figured out how to 100% guarantee I'd get an alien without any extra luck.
Read on to find out how I did it, how you can too, and how developers can avoid it!
How to make rare NFTs without luck.

# How to mint rare NFTs without needing luck

For example, once I knew my alien was #4002, I simply refreshed the mint page until #3992 was minted, and then mint 10 mphers.

How did I know #4002 was extraterrestrial? Let's go back.

First, go to the mpher contract's Etherscan page and look up the tokenURI of a previously issued token, token #1:

As you can see, mphers creates metadata URIs by combining the token id and an IPFS hash.

This method gives you the collection's provenance in every URI, and while that URI can be changed, it affects everyone and is public.

Consider a token URI without a provenance hash, like https://mphers.art/api?tokenId=1.
As a collector, you couldn't be sure the devs weren't changing #1's metadata at will.
The API allows you to specify “if #4002 has not been minted, do not show any information about it”, whereas IPFS does not allow this.

It's possible to look up the metadata of any token, whether or not it's been minted.
Simply replace the trailing “1” with your desired id.

Mpher #4002

These files contain all the information about the mpher with the specified id. For my alien, we simply search all metadata files for the string “alien mpher.”

Take a look at the 6,969 meta-data files I'm using OpenSea's IPFS gateway, but you could use ipfs.io or something else.

Use curl to download ten files at once. Downloading thousands of files quickly can lead to duplicates or errors. But with a little tweaking, you should be able to get everything (and dupes are fine for our purposes).
Now that you have everything in one place, grep for aliens:

The numbers are the file names that contain “alien mpher” and thus the aliens' ids.
The entire process takes under ten minutes. This technique works on many NFTs currently minting.

In practice, manually minting at the right time to get the alien is difficult, especially when tokens mint quickly. Then write a bot to poll totalSupply() every second and submit the mint transaction at the exact right time.

You could even look for the token you need in the mempool before it is minted, and get your mint into the same block!

However, in my experience, the “big” approach wins 95% of the time—but not 100%.
“Am I being set up all along?”

Is a question you might ask yourself if you're new to this.
It's disheartening to think you had no chance of minting anything that someone else wanted.
But, did you have no opportunity? You had an equal chance as everyone else!
Take me, for instance: I figured this out using open-source tools and free public information. Anyone can do this, and not understanding how a contract works before minting will lead to much worse issues.

The mpher mint was fair.

While a fair game, “snipe the alien” may not have been everyone's cup of tea.
People may have had more fun playing the “mint lottery” where tokens were distributed at random and no one could gain an advantage over someone simply clicking the “mint” button.

How might we proceed?
Minting For Fashion Hats Punks, I wanted to create a random minting experience without sacrificing fairness. In my opinion, a predictable mint beats an unfair one. Above all, participants must be equal.

Sadly, the most common method of creating a random experience—the post-mint “reveal”—is deeply unfair. It works as follows:

• During the mint, token metadata is unavailable. Instead, tokenURI() returns a blank JSON file for each id.
• An IPFS hash is updated once all tokens are minted.
• You can't tell how the contract owner chose which token ids got which metadata, so it appears random.

Because they alone decide who gets what, the person setting the metadata clearly has a huge unfair advantage over the people minting. Unlike the mpher mint, you have no chance of winning here.
But what if it's a well-known, trusted, doxxed dev team? Are reveals okay here?
No! No one should be trusted with such power. Even if someone isn't consciously trying to cheat, they have unconscious biases. They might also make a mistake and not realize it until it's too late, for example.

You should also not trust yourself. Imagine doing a reveal, thinking you did it correctly (nothing is 100%! ), and getting the rarest NFT. Isn't that a tad odd Do you think you deserve it? An NFT developer like myself would hate to be in this situation.

Reveals are bad*

UNLESS they are done without trust, meaning everyone can verify their fairness without relying on the developers (which you should never do).
An on-chain reveal powered by randomness that is verifiably outside of anyone's control is the most common way to achieve a trustless reveal (e.g., through Chainlink).

Tubby Cats did an excellent job on this reveal, and I highly recommend their contract and launch reflections. Their reveal was also cool because it was progressive—you didn't have to wait until the end of the mint to find out.

In his post-launch reflections, @DefiLlama stated that he made the contract as trustless as possible, removing as much trust as possible from the team.

And @DefiLlama is a superstar developer. Imagine how much stress maximizing trustlessness will cause you!

That leaves me with a bad solution that works in 99 percent of cases and is much easier to implement: random token assignments.

Introducing ERC721R: A fully compliant IERC721 implementation that picks token ids at random.

ERC721R implements the opposite of a reveal: we mint token ids randomly and assign metadata deterministically.
This allows us to reveal all metadata prior to minting while reducing snipe chances.
Then import the contract and use this code:

What is ERC721R and how does it work

First, a disclaimer: ERC721R isn't truly random. In this sense, it creates the same “game” as the mpher situation, where minters compete to exploit the mint. However, ERC721R is a much more difficult game.
To game ERC721R, you need to be able to predict a hash value using these inputs:

This is impossible for a normal person because it requires knowledge of the block timestamp of your mint, which you do not have.

To do this, a miner must set the timestamp to a value in the future, and whatever they do is dependent on the previous block's hash, which expires in about ten seconds when the next block is mined.

This pseudo-randomness is “good enough,” but if big money is involved, it will be gamed. Of course, the system it replaces—predictable minting—can be manipulated.
The token id is chosen in a clever implementation of the Fisher–Yates shuffle algorithm that I copied from CryptoPhunksV2.

Consider first the naive solution: (a 10,000 item collection is assumed):

1. Make an array with 0–9999.
2. To create a token, pick a random item from the array and use that as the token's id.
3. Remove that value from the array and shorten it by one so that every index corresponds to an available token id.

This works, but it uses too much gas because changing an array's length and storing a large array of non-zero values is expensive.

How do we avoid them both? What if we started with a cheap 10,000-zero array? Let's assign an id to each index in that array.

Assume we pick index #6500 at random—#6500 is our token id, and we replace the 0 with a 1.

But what if we chose #6500 again? A 1 would indicate #6500 was taken, but then what? We can't just "roll again" because gas will be unpredictable and high, especially later mints.

This allows us to pick a token id 100% of the time without having to keep a separate list. Here's how it works:

1. Make a 10,000 0 array.
2. Create a 10,000 uint numAvailableTokens.
3. Pick a number between 0 and numAvailableTokens. -1
4. Think of #6500—look at index #6500. If it's 0, the next token id is #6500. If not, the value at index #6500 is your next token id (weird!)
5. Examine the array's last value, numAvailableTokens — 1. If it's 0, move the value at #6500 to the end of the array (#9999 if it's the first token). If the array's last value is not zero, update index #6500 to store it.
6. numAvailableTokens is decreased by 1.
7. Repeat 3–6 for the next token id.

So there you go! The array stays the same size, but we can choose an available id reliably. The Solidity code is as follows:

GitHub url

Unfortunately, this algorithm uses more gas than the leading sequential mint solution, ERC721A.

This is most noticeable when minting multiple tokens in one transaction—a 10 token mint on ERC721R costs 5x more than on ERC721A. That said, ERC721A has been optimized much further than ERC721R so there is probably room for improvement.

Conclusion

Listed below are your options:

• ERC721A: Minters pay lower gas but must spend time and energy devising and executing a competitive minting strategy or be comfortable with worse minting results.
• ERC721R: Higher gas, but the easy minting strategy of just clicking the button is optimal in all but the most extreme cases. If miners game ERC721R it’s the worst of both worlds: higher gas and a ton of work to compete.
• ERC721A + standard reveal: Low gas, but not verifiably fair. Please do not do this!
• ERC721A + trustless reveal: The best solution if done correctly, highly-challenging for dev, potential for difficult-to-correct errors.

Did I miss something? Comment or tweet me @dumbnamenumbers.
Check out the code on GitHub to learn more! Pull requests are welcome—I'm sure I've missed many gas-saving opportunities.

Thanks!

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What are pre-sales and whitelists on NFTs?

An NFT pre-sale, as the name implies, allows community members or early supporters of an NFT project to mint before the public, usually via a whitelist or mint pass.

Coin collectors can use mint passes to claim NFTs during the public sale. Because the mint pass is executed by “burning” an NFT into a specific crypto wallet, the collector is not concerned about gas price spikes.

A whitelist is used to approve a crypto wallet address for an NFT pre-sale. In a similar way to an early access list, it guarantees a certain number of crypto wallets can mint one (or more) NFT.

New NFT projects can do a pre-sale without a whitelist, but whitelists are good practice to avoid gas wars and a fair shot at minting an NFT before launching in competitive NFT marketplaces like Opensea, Magic Eden, or CNFT.

Should NFT projects do pre-sales or whitelists? 👇

The reasons to do pre-sales or a whitelist for NFT creators:

Time the market and gain traction.

Pre-sale or whitelists can help NFT projects gauge interest early on.

Whitelist spots filling up quickly is usually a sign of a successful launch, though it does not guarantee NFT longevity (more on that later). Also, full whitelists create FOMO and momentum for the public sale among non-whitelisted NFT collectors.

If whitelist signups are low or slow, projects may need to work on their vision, community, or product. Or the market is in a bear cycle. In either case, it aids NFT projects in market timing.

Reward the early NFT Community members.

Pre-sale and whitelists can help NFT creators reward early supporters.

First, by splitting the minting process into two phases, early adopters get a chance to mint one or more NFTs from their collection at a discounted or even free price.

Did you know that BAYC started at 0.08 eth each? A serum that allowed you to mint a Mutant Ape has become as valuable as the original BAYC.

(2) Whitelists encourage early supporters to help build a project's community in exchange for a slot or status. If you invite 10 people to the NFT Discord community, you get a better ranking or even a whitelist spot.

Pre-sale and whitelisting have become popular ways for new projects to grow their communities and secure future buyers.

Prevent gas wars.

Most new NFTs are created on the Ethereum blockchain, which has the highest transaction fees (also known as gas) (Solana, Cardano, Polygon, Binance Smart Chain, etc).

An NFT public sale is a gas war when a large number of NFT collectors (or bots) try to mint an NFT at the same time.

Competing collectors are willing to pay higher gas fees to prioritize their transaction and out-price others when upcoming NFT projects are hyped and very popular.

Pre-sales and whitelisting prevent gas wars by breaking the minting process into smaller batches of members or season launches.

The reasons to do pre-sales or a whitelists for NFT collectors:

How do I get on an NFT whitelist?

1. Popular NFT collections act as a launchpad for other new or hyped NFT collections.

Example: Interfaces NFTs gives out 100 whitelist spots to Deadfellaz NFTs holders. Both NFT projects win. Interfaces benefit from Deadfellaz's success and brand equity.

In this case, to get whitelisted NFT collectors need to hold that specific NFT that is acting like a launchpad.

1. A NFT studio or collection that launches a new NFT project and rewards previous NFT holders with whitelist spots or pre-sale access.

The whitelist requires previous NFT holders or community members.

NFT Alpha Groups are closed, small, tight-knit Discord servers where members share whitelist spots or giveaways from upcoming NFTs.

The benefit of being in an alpha group is getting information about new NFTs first and getting in on pre-sale/whitelist before everyone else.

There are some entry barriers to alpha groups, but if you're active in the NFT community, you'll eventually bump into, be invited to, or form one.

1. A whitelist spot is awarded to members of an NFT community who are the most active and engaged.

This participation reward is the most democratic. To get a chance, collectors must work hard and play to their strengths.

Whitelisting participation examples:

• Raffle, games and contest: NFT Community raffles, games, and contests. To get a whitelist spot, invite 10 people to X NFT Discord community.
• Fan art: To reward those who add value and grow the community by whitelisting the best fan art and/or artists is only natural.
• Giveaways: Lucky number crypto wallet giveaways promoted by an NFT community. To grow their communities and for lucky collectors, NFT projects often offer free NFT.
• Activate your voice in the NFT Discord Community. Use voice channels to get NFT teams' attention and possibly get whitelisted.

The advantage of whitelists or NFT pre-sales.

Chainalysis's NFT stats quote is the best answer:

Sure, it's not all about cash. However, any NFT collector should feel secure in their investment by owning a piece of a valuable and thriving NFT project. These stats help collectors understand that getting in early on an NFT project (via whitelist or pre-sale) will yield a better and larger return.

The downsides of pre-sales & whitelists for NFT creators.

Pre-sales and whitelist can cause issues for NFT creators and collectors.

NFT flippers

NFT collectors who only want to profit from early minting (pre-sale) or low mint cost (via whitelist). To sell the NFT in a secondary market like Opensea or Solanart, flippers go after the discounted price.

For example, a 1000 Solana NFT collection allows 100 people to mint 1 Solana NFT at 0.25 SOL. The public sale price for the remaining 900 NFTs is 1 SOL. If an NFT collector sells their discounted NFT for 0.5 SOL, the secondary market floor price is below the public mint.

This may deter potential NFT collectors. Furthermore, without a cap in the pre-sale minting phase, flippers can get as many NFTs as possible to sell for a profit, dumping them in secondary markets and driving down the floor price.

Hijacking NFT sites, communities, and pre-sales phase

People try to scam the NFT team and their community by creating oddly similar but fake websites, whitelist links, or NFT's Discord channel.

Established and new NFT projects must be vigilant to always make sure their communities know which are the official links, how a whitelist or pre-sale rules and how the team will contact (or not) community members.

Another way to avoid the scams around the pre-sale phase, NFT projects opt to create a separate mint contract for the whitelisted crypto wallets and then another for the public sale phase.

Scam NFT projects

We've seen a lot of mid-mint or post-launch rug pulls, indicating that some bad NFT projects are trying to scam NFT communities and marketplaces for quick profit. What happened to Magic Eden's launchpad recently will help you understand the scam.

We discussed the benefits and drawbacks of NFT pre-sales and whitelists for both projects and collectors. 

Finally, some practical tools and tips for finding new NFTs 👇

Tools & resources to find new NFT on pre-sale or to get on a whitelist:

In order to never miss an update, important pre-sale dates, or a giveaway, create a Tweetdeck or Tweeten Twitter dashboard with hyped NFT project pages, hashtags ( #NFTGiveaways , #NFTCommunity), or big NFT influencers.

Search for upcoming NFT launches that have been vetted by the marketplace and try to get whitelisted before the public launch.

Save-timing discovery platforms like sealaunch.xyz for NFT pre-sales and upcoming launches. How can we help 100x NFT collectors get projects? A project's official social media links, description, pre-sale or public sale dates, price and supply. We're also working with Dune on NFT data analysis to help NFT collectors make better decisions.

Don't invest what you can't afford to lose because a) the project may fail or become rugged. Find NFTs projects that you want to be a part of and support.

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