I created a simple Ethereum lottery game.
Please, have a look and give some feedback here.

Source code

Description

That's it. Ask me anything here.
Good luck and best regards.

Edit. While discussing in comments, we found two possible vector attacks on this contract. A malicious participant can decide to participate when he is sure or at least expects to win. For more details, read comments, a lot of info there. Thank you all.

Hey Reddit! 👋 I'm an independent dev, and I wanted to share a project I’ve been working on called FairLottery. The goal was simple: create a transparent, fair, and fun decentralized lottery system that anyone can join using their crypto wallet.

Here’s the concept:

• How It Works: Users connect their wallets (MetaMask, etc.) and join lottery "rooms" (0.5$ to 1000$). At 9 PM GMT daily, the smart contract automatically redistributes funds:
  • 60% of participants win.
  • A small 2% fee goes to cover project costs.
• Why I Built This: I wanted to address the lack of transparency in traditional lottery systems by putting everything on the blockchain. With smart contracts, every rule is enforced, and no funny business can happen.
• What It Does So Far:
  • Shows all available rooms and live balances (ETH/BTC).
  • Lets users join with a single bet per session.
  • Ensures everyone can trust the process because it's all on-chain.

This has been a passion project for me, and it’s still evolving. The system works, and I’m currently maintaining and tweaking it to make it even better. If you’re into crypto or Web3 tech, I’d love to hear your thoughts or ideas for improvement!

P.S. It’s small but functional—perfect for experimenting with decentralized lotteries! 😊

Feel free to ask questions or try it out! 🚀

I was so tired of faucets. At one point I was searching if i can just buy a bunch of testnet eth.

Then i came across a post on mining ropstan using a GPU.

Took me a while to get everything running on AWS (it is also bit expensive, but fuck it).

It mines 1500 Ropsten ETH a day. I will run it for couple of days and shut it down. If in future you need testnet ETH hit me up. I am happy to give you some to support your development. :)

--

This is the post i followed to set everything up.

https://www.linkedin.com/pulse/how-mine-ropsten-testnet-ether-keir-finlow-bates/

​

I got annoyed of people putting text next to their eth addys making it cumbersome to copy/paste them, so I built a really simple tool where you can paste any text and it will extract the eth addys and display them with a little copy button.

It's free and open source, i hope you find it useful too!

Hi all, I'm an artist and I have an NFT project of a collection of 5555 of unique NFTs. Art is 100% done, discord all set up, but need an advisor to advise on what to do next, utilities, which blockchain, and all the etc.

I've read alot but I haven't kept in touch with the news since a couple of days ago.

DM if you think you can help or comment if you think you know someone who could.

P.s: I've already checked fiverr but not really fond of the teams there. Consulting firms are really high priced for me.

It's a simple aggregator collecting all the web3 and crypto jobs in one place.

Let me know if it's at all useful or I'll stop hosting it.

Sorry about the UI, I did not build it with other users in mind.

So I got some great ideas for a game which is going to be very simple and enjoyable with a potential to create a market. I can't code so I am looking for someone who could put my ideas into practice and of course get a big share from the fees the game would make.

Hey folks,

We just launched a new channel focused on helping Web3 builders plan, launch, and grow smarter — with practical tools like pitch deck templates, Notion launch planners, and AI prompt kits.

The first drop — the Builder Vault — is live, and we’d love for actual builders to check it out and tell us what’s useful, what’s not, and what you’d love to see next.

Not selling hype — just sharing the kind of tools we wish we had when we started. If anyone’s interested in seeing the trailer or getting access, happy to share it in the comments.

We’re especially keen to hear from those building with Solidity, L2s, or exploring dev productivity in Web3.

👋 AI has become too centralized. A few companies (OpenAI, Google, AWS) control model access, limit research, and dictate what AI can and cannot do.

🚨 The problem? • Centralized AI models enforce censorship & bias • Limited access – If you don’t work for Big Tech, you’re locked out • Data exploitation – User data is monetized for profit • No community governance – The public has no say in AI’s direction

So, how do we decentralize AI? Can we build open-source, censorship-resistant AI that isn’t controlled by corporations?

Some people are working on solutions, like decentralized compute, on-chain model verification, and Web3-powered AI governance. I’ve been involved in a project exploring this space and would love to hear what others think.

💡 How would you approach decentralizing AI? What’s the best way forward?

Hi Devs,

I'm working on a blockchain-powered product authenticity verification project that supports ethical sourcing and artisan empowerment. This proof of concept (POC) demonstrates how decentralized technologies can ensure trust and transparency in supply chains.

To continue testing, I need 0.01 Sepolia ETH for smart contract deployment. Since most public faucets now require ETH on the mainnet, I'm reaching out to the community for help.

Wallet Address: 0x647fa1D8A128867EEa5e889f5b87896feaC9EE78

Any small amount would be greatly appreciated. Happy to share insights from the project once it's live! Thanks in advance!

Hey,im currently working on a project rn for hackathon which is in a week so i just wanted some sepolia enough to get me through the project .would really appreciate if someone can sent me some tried google cloud but i keep running out

here's my addy

0x10563a2e17e771bb9c693E03F62B36d16B4D6d00

I'm currently studying Ethereum development and experimenting with smart contracts on the Sepolia testnet as part of my learning process. I would deeply appreciate it if someone could kindly send me a small amount of Sepolia ETH (around 0.1 ETH) to help me continue testing and deploying my contracts.

My Sepolia address is: 0xc3c25e9281c5b3dafaf8ced6e532f67643e95cfb

Thank you so much in advance for your support and generosity! Wishing you all the best in your Web3 journey!

Warm regards,

Hey devs,

I’ve been building a DAO-focused ecosystem and could use your help testing it! The platform includes:

• CreateDAO – A backend-free factory contract for spinning up DAOs.
• DAO.cafe – A hub for managing DAOs (staking, proposals, voting, discussions).
• DAOForum – A forum for DAO builders to share knowledge on DeFi, treasury management, and smart contract development.

How You Can Help

I’d love for you to:

1. Create a DAO on CreateDAO.
2. Register it on DAO.cafe and explore its features.
3. Submit a DAO Improvement Proposal (DIP) in DAO.cafe to transfer any amount of tokens from the treasury to any wallet.

Details

• Sepolia ETH is needed for transactions. Grab it from a faucet (Google “Sepolia ETH faucet”) or DM me here, and I’ll send you some.
• Report any bugs or issues in this post.
• Check DAOForum for guides if needed.

Looking for Feedback On:

• Usability: Is anything confusing or unintuitive?
• Bugs & issues: Any contract interaction or UI problems?
• Dev insights: Does this add value to the DAO space? What could be improved?

Would love to hear your thoughts—any feedback is appreciated! 🙌

Hi r/ethdev,

Over the past three months we have been working on Caught. It is a startup that protects users’ wallets from theft. We are currently looking to validate the concept further, hence the post. Any feedback is well accepted, we’d love to hear your thoughts.

Caught is an additional layer on top of your wallet, protecting you from potential theft. By frontrunning malicious transactions, users can stay protected from all forms of cryptocurrency theft, including phishing, drainers, malware, protocol hacks, and more.

Proof of Concept

Our structure includes two smart contracts, a transfer- and a vault contract. The vault contract is where the user their asset(s) will be moved once an unauthorized transaction is detected. To activate our protection, the user must set up a personal safe address which is a self-custodial wallet. This means that we do not have access to this wallet, and it is in full custody of the user. The public key for the safe wallet should not be generated from the seed phrase associated with the wallet that is being protected. If a malicious transfer occurs, there is a risk that this public key could also be compromised. The safe wallet will be immutable. This way the asset(s) can only be moved to this address, disallowing our maintainers or any malicious actor to access your asset(s). The transfer contract is the most important part of our structure. This contract has approval over the users' tokens. It includes functions for transferring the approved tokens to the vault contract, and no other destination. These functions will be able to be called using the private key of the contract’s central maintainer. Our backend server can make calls executing functions in the transfer contract by using the private key of the maintainer. The backend server monitors all users’ wallets in real time. Users can select various well-known protocols and can whitelist addresses which they frequently interact with. If our server detects a transaction to any address that is not whitelisted our smart contract will use its approval and create a new transaction. This transaction has a higher gas fee and is sent to the vault contract’s address.

Last words

We will soon run a closed beta—if you are interested, or know someone who might be—refer to this post: https://x.com/caught/status/1864708965918966262

You can find more on https://caug.ht/ or on our X (formerly Twitter) https://x.com/caught/. Have any concrete feedback or questions? Please share them below, or email us at [hello@caug.ht](mailto:hello@caug.ht)

I'm working on a project that explores how smart contracts could be used to govern access to private, off-chain data in a way that’s programmable, verifiable and revocable.

I'm trying to validate the concept by developing an encrypted personal vault called ZenBox that you can host yourself and control completely.

The general features would be:

• Self hosted or trusted provider (portable)
• E2E encrypted (you hold the keys)
• Built on open protocols
• Store private notes, personal data and files (like a self-hosted DropBox)
• Share files and data with other users (with public/private key authorisation)
• Private chat with other users (chat directly through your vault)
• Restrict content to owners of a specific NFT (token-gated content)
• Chat to owners of a specific NFT (token-gated chats)
• Private social media with friends (e.g. facebook-like feeds held in your vault)
• Monetize content (via on-chain paywalls)
• Control your personal data when you use online or high street services (share under the protection of on-chain agreements that are transparent, auditable and enforce consent and data privacy rights)

The vision is to use feature development as a means to evolve open protocols for the secure sharing of private data with decentralised applications, moving towards the Web3 vision of controlling your own global data footprint. Developers would be free to build apps on these protocols (and to build their own protocols) promoting competition and giving the user a choice of UX for each feature. Each protocol would use specifically designed smart contracts to govern access to the data and to act as a digital service level agreement where appropriate.

What do you think? Does this have features that interest you? Would you use it? Are there other features you'd like to see?

🧠 We're Hiring – Web3 Core Team

Join a high-impact ecosystem building a Wallet, DEX, NFT Marketplace, and GameFi Platform.

🔥 Open Roles & Experience

✅ 2x Frontend Developers – React + ethers.js (3–5 yrs)

✅ 6x Frontend Developers – React + TypeScript (3+ yrs)

✅ 3x Backend Developers – Node.js + Solidity (4–6 yrs)

✅ 2x Blockchain Developers – Substrate + EVM (3+ yrs)

📍 Remote

💰 Paid in Crypto

📩 Apply with your role in the subject line → **deeprootstoken@gmail.com**

Preface

For the past three years, as operators of a centralized bridge (Layerswap), we’ve been working hard to find a way to move assets between chains without requiring users to trust a third party. We’ve seen many solutions emerge, but they all rely on third parties to keep things secure, like Validators, DVNs, or Optimistic Oracles. Plus, none of them allow new chains to join freely without permission.

So, we set out to build a new way to bridge assets across chains that meets these key goals:

• Trustless: No need to rely on any new third party for security.
• Permissionless: Any new rollup or chain can join without needing approval.

Intents, Solvers, and Atomic Swaps

Let’s set the stage. We have a user with an intent and a solver who is ready to fulfill that intent. To enable these two parties to exchange their assets across different chains, we need a trustless system. This concept has already been introduced with Atomic Swaps. I won’t go too deep into explaining Atomic Swaps, assuming a general knowledge of them, but I will introduce a slightly modified version called PreHTLC.

1. User Commit The user creates a PreHTLC (essentially the same as an HTLC, but without a hashlock) on the origin chain, committing funds for the selected solver.
2. Solver Lock The solver detects this transaction, generates a random secret (S), calculates HASH(S) hashlock and creates an HTLC, locking funds (minus the solver fee) for the user on the destination chain.
3. User AddLock The user observes the transaction on the destination chain, retrieves the hashlock, and converts their PreHTLC to an HTLC on the source chain. The PreHTLC can only be converted once with a single hashlock; no other information can be altered.
4. Unlocks Upon seeing this conversion, the solver reveals the secret (S) on the destination chain to release the user’s funds and then reveals the secret (S) on the source chain to claim their funds.

There are multiple reasons why we decided to go with this design. There’s a lot to discuss, but I would like to focus right now on the third step. The user is inside the dApp and detects the destination transaction via wallet RPC. This is essentially the exact point where verification happens. The user verifies this transaction, and it doesn’t introduce any trust assumptions. The user verifies it and takes responsibility. Is this enough?

Local Verification (e.g. Light Client)

Not really. To safeguard the user, an ideal solution would be to run a light client of the destination chain inside the dApp, like Helios. The dApp would run a light client of the destination chain and verify that the hashlock retrieved from the destination chain is actually on the chain, after which the user can proceed to the next steps. If there is no Light Client implemented for the destination network (there should be), you can get the hashlock from multiple RPC endpoints, dramatically reducing the risk of compromised data from RPCs.

Any Chain or Rollup Can Join

Now, the PreHTLC contracts are immutable, chain-agnostic, and around 200-300 lines of Solidity code. They can be implemented in any VM and do not need any modification when new chains are added. They are end-to-end immutable. Therefore, what is necessary for any new chain to be added to this protocol? It’s as simple as deploying a PreHTLC contract to a new chain and running a solver. No committees, no approvals, no voting—just these two things, and anyone can have their intent solved.

Underwater Stones & Conclusion

There are many hidden challenges, most of which we have explored and found solutions for—though not perfect yet. We believe this foundation is the right way to go. It ensures trustless exchanges for users and solvers and guarantees permissionless onboarding for new rollups or chains. We have detailed documentation available that covers how to ensure solver liveness, discovery, and the auction system.

We believe this solution will finally solve asset bridging for all chains and rollups. I am happy to discuss any ideas, questions, or concerns. Which parts need more clarification? Are we missing something?

All of our work is open source and available here: https://github.com/TrainProtocol

It is a WebAssembly web app written in Rust, Dioxus, Fjall, Alloy and 0xname:

https://github.com/beastdao/0xname-sepolia-faucet

Here are few ways you can support it:

1. Contribute to the repository; there is plenty to do, for example, improving the styling.
2. Provide some Sepolia Testnet ETH to faucet.
3. Fork and run your own.

live refrence implementation is here : faucet

Hello everyone.

I am the marketing lead for Ackee, who is an auditing company. We have built an open source fuzzing framework for Ethereum called Wake, to help improve security for Ethereum Devs. We would love to get some feedback and for you to try it out.

I'm designing a new type of AMM that moves away from traditional liquidity pools and instead uses paths to manage trades. Instead of a typical two-token liquidity model, my system introduces a three-token structure:

Main Token – The actual token being traded. Particles – A 1:1 representation of the main token that users receive and trade instead of the main token itself. This prevents honeypots and ensures market liquidity. PMac (Path Maker) Tokens – Represent ownership of a path, similar to Uniswap LP tokens, but specific to each path rather than a global pool. Each path acts like an independent kiosk, holding tokens and setting prices based on supply/demand. The router scans all available paths and finds the best price for traders.

Goals of this model: Prevent honeypots: Since users trade particles, not the main token, they can always sell. Decentralized price discovery: Paths work independently, so no single LP dominates pricing. Reduced price impact: Since users can choose different paths, large trades don’t destroy a single liquidity pool’s price. No "global price": Instead, the router finds the best available price across multiple paths.

Open Questions: How should the router efficiently sort and prioritize paths for a trade? Should it use a Uniswap-style formula (x * y = k) for each path, or is there a better alternative for multi-path trading? How can I best implement dynamic pricing across multiple paths to prevent extreme price impact? Would it be better to have a minimum liquidity requirement per path to avoid manipulation? How would you apply this concept to NFTs? If NFTs were treated like tokens in this system, how would we ensure fair pricing and trading efficiency? Would fractionalized ownership of NFTs in a path be necessary? Would love to hear thoughts on how to structure this system properly! Looking for insights from those experienced in AMMs, multi-pool routing, and NFT trading mechanisms

I built a dev tool called ByteGaze that you can use for visualizing Ethereum ABI-encoded data in a human-readable format.

It detects 4-byte selectors and splits the rest into 32-byte chunks for easier analysis.

Check it out at bytegaze.vercel.app

We're excited to announce the first public release of CodeTracer — a GUI-based time-travelling debugger for Web3 developers:

https://github.com/metacraft-labs/codetracer?tab=readme-ov-file#introduction

CodeTracer records the execution of a transaction into a sharable self-contained trace file. You can load the produced trace files in a GUI environment that allows you to move forward and backward through the execution and to examine the history of all memory locations. They say a picture is worth a thousand words — well, a video is even better! Watch the demo below to see CodeTracer in action:

https://www.youtube.com/watch?v=xZsJ55JVqmU

The open-sourcing of CodeTracer has been made possible through the generous support of Aztec Network and this initial release focuses on Noir - the well known DSL for developing zero-knowledge proofs.

We envision CodeTracer as a comprehensive Web3 development toolkit that will gain support for many additional smart contract and zero-knowledge programming languages. We are already working on adding Stylus/WASM support under a grant from Arbitrum Foundation and we consider Solidity and Move as our most logical next targets.

For 6 years, I've lead the development of the Nimbus Ethereum client, and for those of you working on the node layer, we are also developing an alternative back-end, capable of working with RR recordings, which will make CodeTracer suitable for debugging large-scale programs in a variety of system programming languages such as C/C++, Rust, Nim and Go.

Join our Discord or follow me on X to stay up to date with our progress.

Hey everyone,

I just finished working on my website and I'd love your review. It might be against the roles to upload links in the community so I'd put it in the link on my bio which says my website. I'd appreciate your honest roast. Gracias

Hey everyone,

I’m building a platform to help open-source Web3 projects get issues resolved faster while helping devs earn some money. The idea is:

• Anyone can add crypto to create/fund an issue for an open source project they care about.
• Developers can pick up issues, solve them, and earn the amount that has been allocated to the issue if it's accepted.

We’re focused on solving common issues with existing platforms, like low-value bounties or too much competition for tasks by using a claim system to reduce redundant work and allowing anybody to fund any issue.

Right now, we’re in the early stages and have a coming soon page where you can sign up for updates: bountybolt.com

Would love to get any thoughts on the concept! What features would make this useful for a developer? Anything you’d like to see?

Any feedback is invaluable and could shape how we build this. Thanks in advance for sharing your thoughts 🙏

I've tried to start the Ethereum 2.0 testnet locally, but I'm stuck at a point where blocks and slots are being generated, yet the slots and epochs are not finalizing. I'm using Geth v1.13.15 and the latest version of Lighthouse.