The ultimate guide to hiring a web developer in 2021
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Blockchain, is a technology that encompasses digital records or information, referred to as “blocks”, that are linked together securely and share the same network. This distributed ledger technology is the backbone of a new wave of innovation being implemented into our lives, with new disruptive applications and solutions seen in a growing number of industries. Clients may hire a Blockchain Developer to harness this power and build a secure digital platform tailored to their business needs.
A Blockchain Developer can create unique solutions leveraging blockchain technology to securely store, access, mine and distribute data in an efficient manner. They can leverage features such as blockchain tokens for payments, smart contracts for automated transactions, privacy layers and data protection techniques. Additionally, the expertise of a Blockchain Developer will ensure the project complies with industry standards, ensuring secure data and validation.
Here's some projects that our expert Blockchain Developer made real:
At Freelancer.com customers have posted amazing projects covering a variety of use cases related to blockchain utilising the Freelancer verified experts. With help from professionals on Freelancer.com customers can create unique projects addressing their business needs with safety, security and legality in mind. Rock your blockchain project today and hire an expert Blockchain Developer on Freelancer.com now!
Asiakkaamme antoivat 79,643 arvostelussa keskimääräisen arvosanan Blockchain Developers 4.9 / 5 tähteä.Blockchain, is a technology that encompasses digital records or information, referred to as “blocks”, that are linked together securely and share the same network. This distributed ledger technology is the backbone of a new wave of innovation being implemented into our lives, with new disruptive applications and solutions seen in a growing number of industries. Clients may hire a Blockchain Developer to harness this power and build a secure digital platform tailored to their business needs.
A Blockchain Developer can create unique solutions leveraging blockchain technology to securely store, access, mine and distribute data in an efficient manner. They can leverage features such as blockchain tokens for payments, smart contracts for automated transactions, privacy layers and data protection techniques. Additionally, the expertise of a Blockchain Developer will ensure the project complies with industry standards, ensuring secure data and validation.
Here's some projects that our expert Blockchain Developer made real:
At Freelancer.com customers have posted amazing projects covering a variety of use cases related to blockchain utilising the Freelancer verified experts. With help from professionals on Freelancer.com customers can create unique projects addressing their business needs with safety, security and legality in mind. Rock your blockchain project today and hire an expert Blockchain Developer on Freelancer.com now!
Asiakkaamme antoivat 79,643 arvostelussa keskimääräisen arvosanan Blockchain Developers 4.9 / 5 tähteä.I’m opening this room so we can collaborate one-on-one on the assignment we previously discussed. Here is a mini-project that is a small test before committing to a larger project. Part A — Sports Market Identification (uses my existing files): Parse the full file (264K events, 2.8 GB) and extract every unique tag across all events. Deliver the complete tag list and identify which ones are sports. Then produce the definitive list of sports markets for a single sport only — pick NBA. Give me every NBA market with its conditionId, clobTokenIds, event title, market question, outcomes, and settlement result. This proves you can work with the existing data, understand the event-market-tag hierarchy, and handle the stringified JSON quirk. Part B — On-Chain Trade Extra...
Project description Startup Backend / DevOps Engineer (Growth Opportunity) We are a US-registered technology company building a fintech compliance platform and related backend infrastructure tools. We are looking for a motivated junior engineer who wants to grow into a Backend / DevOps role. This is a long-term opportunity for someone early in their career who wants real startup experience, direct responsibility, and room to grow. You will work directly with the founder and help manage backend systems, deployments, repository workflows, and code integration. Project Type Long-term monthly engagement (part-time). This is not a one-time task. Responsibilities Manage Git repositories, branches, and merge requests in GitLab Maintain and troubleshoot CI/CD pipelines Deploy backend services a...
I need to build a complete dataset of every individual trade ever executed on sports betting markets on Polymarket, a prediction market platform running on the Polygon blockchain. The end goal is a structured file where each row represents a single trade fill, containing the wallet address, the market and event it belongs to, which sport/league it falls under, the outcome being traded, price per share, number of shares, USDC amount, timestamp, transaction hash, and whether that wallet was the maker or taker. Each row should also include the settlement result of that market (which outcome won) so that I can calculate profit and loss on my own. The dataset needs to be granular and complete enough that I can perform any analysis I want on trader behavior, performance, and patterns after deliv...
*Complete SOW attached* I am building a full-featured marketplace where owners of both residential and commercial properties can publish listings, buyers can search and signal interest, and an admin dashboard lets me review uploaded documents before anchoring each verified listing on-chain for tamper-proof proof of authenticity (NFT minting or a hash stored on a public ledger). Core user flows • Owners: sign up, complete KYC, create listings with photos, videos, and supporting documents. • Buyers: intuitive search and filtering, the ability to “favourite” or otherwise express interest in a property, and direct access to the blockchain-stamped document set once a listing is verified. • Administrators: role-based panel to inspect deeds, titles, permits, t...
I need a full-stack developer (or team) who can take this project from concept to deployment: a professional-grade crypto investment and USDT exchange platform with a clean, modern fintech UI and a rock-solid, secure backend. Core user flow • Visitors create an account, deposit USDT through an on-site wallet integration, select from several investment plans, track earnings in a personal dashboard, and submit withdrawal requests when ready. • An admin console gives me total oversight of users, deposits, withdrawals, plans, and the full transaction log. Key modules to deliver 1. Registration & login with standard email/password (expandable to 2FA later). 2. Responsive dashboard showing balance, active plans, earnings, and full transaction history. 3. Deposit workflo...
I trade on Polymarket with an algorithmic approach and would like that exact process coded so the system can handle my trades automatically. The core of the job is to translate my current trade-entry and exit rules along with my risk-management parameters into a clean, reliable script that talks to Polymarket’s API (or directly to its smart-contracts if that proves more stable). Here is what I need from you: • A well-structured program—Python is ideal, but I am flexible—that connects to live Polymarket data, evaluates the same indicators I currently watch, and submits orders in real time. • Built-in risk controls matching my current rules: position-size limits, maximum daily drawdown, and automatic exits when predefined levels are hit. • Simple config...
Project Type: Hourly Budget: $25 – $35 / hour Workload: < 30 hrs/week Description We are looking for an experienced Full-Stack Developer with strong experience in React, Django, and Node.js to help build a web application based on a detailed requirements document. The application will include user authentication, protected routes, wallet analytics dashboard, API integrations, and several landing pages. The frontend will use React, while backend services will use Django and Node.js APIs. Responsibilities - Build frontend with React - Implement login / signup authentication - Develop wallet analytics dashboard - Integrate Django and Node.js APIs - Implement protected routes - Build landing pages (Home, Blog, Pricing, About) - Handle real-time data (WebSocket or API polling) Req...
I’m planning a first-person, action-fighting game that lets players earn and spend my existing cryptocurrency directly from their phones. The core loop should feel like a polished console brawler—quick combos, skill-based progression—yet remain lightweight enough to run smoothly on current Android and iOS devices. I already have the token contract live, so wallet connectivity, secure on-chain reward distribution, and an in-game marketplace for cosmetic upgrades are essential. Think of a play-to-earn flow where match results trigger automated payouts, and every purchase or trade is written back to the chain without breaking immersion. Key deliverables • A playable mobile build (Android + iOS) featuring at least one arena, two fighter classes, and basic PvE waves...
I need a fully-functioning demo of a trading platform that I can immediately present to stakeholders and, if it meets our standards, license or purchase outright. Crypto trading is my top priority, yet the ideal solution will also handle stocks and forex so we can scale without switching systems later. The demo should already be built, stable, and visually polished. I’m especially interested in platforms that already include—or can easily enable—real-time market data feeds, automated trading logic, and customizable dashboards. If you have additional standout tools such as risk-management alerts, portfolio analytics, or multi-exchange APIs, highlight them. Because timing is critical, please only respond if: • You can give me instant access to a live or sandbox demo....
⚡️ CALLING ALL CRYPTO-ANARCHISTS & EVM ARCHITECTS ⚡️ Project: The Sovereign Swap Genesis (Phase 1) Forget the $175—we’re here to build the bedrock of permissionless atomic settlement. We are looking for a high-signal Solidity engineer to architect the Sovereign Atomic Swap on Bitnet Money (Sovereign PoW EVM). This isn’t a standard "copy-paste Uniswap" job. This is a research-grade MVP focused on Ownerless Logic, Atomic Finality, and the future of ZK-integrated trustless swaps. If you dream in Opcodes and believe that onlyOwner is a centralized vulnerability, this is your playground. THE ARCHITECTURAL MISSION The objective is to deploy a purely decentralized, non-custodial HTLC (Hashed Time-Lock Contract) on Chain ID 210. We are stripping away the "ad...
我正在构建一个H5,给这个H5集成一套跨平台的 Web3 钱包解决方案,需要在 iOS、Android、Web 以及 Telegram mini app 四端同步实现以下核心功能: 1. WalletConnect 集成 • 支持主流 EVM 链(Ethereum、BSC、Polygon 等) • 自动识别并连接用户现有钱包(MetaMask、okx、binance、abpay等) 2. Mint 功能 • 根据前端表单参数调用合约,完成 ERC-20 / ERC-721 铸造 • 铸造成功后即时回调并更新前端状态 3. 资产转账 • 单笔与批量转账界面 • 手续费预估与确认弹窗 • 转账结果监听与提示 4. 多端 UI/UX 一致性 • 移动端使用 React Native 或 Flutter 均可 • Web 端采用 React + • Telegram mini app 保持相同交互逻辑
Our DApp is live but two areas still misbehave: actions inside the user dashboard do not respond, and token balance / transfer calls occasionally fail or return stale data. I need you to step into the existing React-based codebase, pinpoint what is blocking those interactions, and commit clean, well-documented fixes. You will have direct access to the current repository, smart-contract ABIs, and a staging RPC. The workflow I picture is: • Audit the user-dashboard components, track where clicks or dispatches stall, and restore full responsiveness without breaking current styling. • Trace the Web3 provider hooks that fetch balances and send transfers, correct any state-management or contract-call logic so balances update in real time and transfers resolve every time. • S...
I hold a balance of BTT (“BTTold”) that is still sitting on its original base chain. My goal is to move those tokens onto the Tron network and complete the official swap into the new BTT version. Here is where I currently stand: • The wallet has never—or at least not knowingly—been linked to an exchange, so I may need guidance on that step. What I need from you is a clear, hands-on walkthrough that gets me all the way from “tokens on the base chain” to “new BTT safely in my TronLink wallet (or directly on an exchange account if that is the smoother route).” Acceptance criteria 1. I can see the migrated BTT in my wallet or exchange balance. 2. Transaction hashes are shared so I can independently verify each move on the blockchain...
Senior Full Stack Developer (Fintech / Web3 Product) We are looking for a senior freelance developer to join an active digital product currently under development, focused on digital payments infrastructure, wallet experience, and blockchain-based transactional operations. The project already has a functional technical base and requires someone able to quickly understand an existing architecture, identify critical points, and contribute with solid technical solutions from both engineering and product perspectives. We are not looking for isolated task execution, but for strong technical judgment, scalability mindset, and the ability to solve real product challenges where frontend, transactional logic, and user experience are closely connected. Required Profile Proven senior experience ...
Our dApp’s React-based frontend is live, but the UI stalls whenever it talks to our smart contracts—data can take seconds to appear, and some calls never resolve. Wallet connection and basic transaction flow are in place, yet my top priority is tightening the UI interaction layer so every contract read or write feels instant and reliable. You’ll start by cloning the existing repo, running the current build, and profiling exactly where the slowdown happens. From there, I need you to refactor or replace the offending code—whether that means reworking our hooks, introducing multicall batching, tidying up state management with Redux or Zustand, or simply catching silent promise rejections. The goal is clear: no more sluggish updates, no unhandled errors, and an interf...
I need a complete installation and configuration of a private Hyperledger Besu network whose main job is reliable data storage and sharing. I have servers ready (cloud or on-prem) and want a clean, repeatable setup that lets me add nodes later and expose standard JSON-RPC and WebSocket endpoints. Scope of work • Install the latest stable Besu release on 3+ nodes (validator and non-validator) • Create a custom genesis file, bootnodes list, and network ID • Enable data-storage–focused consensus (IBFT or Clique—whichever you recommend for fast confirmation) • Configure basic account permissioning and privacy groups if they help our data-sharing use case • Expose HTTP & WS APIs with CORS and authentication where needed • Deploy a sampl...
I need a freelancer who have bitcointalk high rank users like Member, Hero or Legendary Need to post and promote my Crypto project with posting.
I run a custom PHP + MySQL website and need a fully self-hosted USDT (TRC20) deposit flow. Here is what the job entails: • Each user must receive an automatically generated, unique TRC20 wallet address. • A service written in the language of your choice should monitor those addresses—either through TronGrid or a locally synchronised Tron node—and detect confirmed USDT transfers in real time. • Once a transfer is confirmed, an SQL call must update the user’s available balance in my existing database tables. • The entire stack must remain under my control; please keep third-party payment gateways (CoinPayments, NowPayments, Plisio, etc.) out of the solution. • Apply standard encryption protocols for key storage, address generation, and an...
Please Note Before Proceeding Below: **This is a small initial project with a limited budget to evaluate the developer’s understanding and quality of work. Once all tasks are completed to our standards, the developer will be hired full-time and considered for larger projects ranging from $5,000 to $25,000, depending on the role and scope.** We are looking for an experienced Solana blockchain developer with strong AWS server infrastructure expertise to help diagnose, fix, and optimize production-level code issues. This is not a beginner role. You must have hands-on experience with Solana programs, RPC interactions, and backend deployment inside AWS environments. You will be working on live Solana-based systems that require debugging, performance optimization, and infrastructure-le...
URGENT: Contract will be done outside the platform 50% after funding presales 50% after launch and will be paid through this platform, the freelancers you will hire will be paid in crypto and fiat. We need a TA Generalist with main talent for acquisition, you need to identify who we need and also why by spotting the best talent for a Memecoin Project Web3 project. We wanna be successful I would consider 10m market cap a success if not higher, we need to launch to market in the shortest time possible. You should have knowledge DeFi ecosystem and HR tools like LinkedIn Recruiter and other tools like DocuSign to make onboarding contracts. Access to AI tools also will be valued highly.
我们需要开发一个支持多种套利策略的加密货币套利交易系统,具体要求如下: 1) 目标 构建一个多交易所加密货币套利交易系统,该系统: • 通过 API 连接多个交易所 • 监控实时价格差异 • 支持多种套利策略 • 提供实时筛选器仪表板 • 支持手动执行以及未来的自动执行 ⸻ 2) 支持的交易所(基于 API) 初始交易所: • Binance • Kraken • Bybit • OKX • Bitget 系统必须采用模块化设计,以便轻松添加新的交易所。 ⸻ 3) 支持的套利策略(核心引擎)系统必须支持:⸻ A) 跨交易所套利 现货-现货 在交易所 A 买入(较低价格) 在交易所 B 卖出(较高价格) 期货-期货 在较低价格的交易所做多 在较高价格的交易所做空 ⸻ B) 现货-期货套利(现金交易) 买入现货 卖出期货 利润来源: • 价格溢价 • 融资利率 • 收敛 ⸻ C) 融资利率套利 基于以下因素在不同交易所采取相反的头寸: • 正/负融资差异 • 净融资收益机会 例如:如果交易所 A 的融资利率为 +0.05%,交易所 B 的融资利率为 -0.03%,系统在进行对冲的同时捕捉融资差异。 ⸻ 4) 入场和出场逻辑(用户控制) 用户必须手动定义: • 入场点差百分比 • 出场点差百分比 • 资金门槛百分比 • 交易规模 • 杠杆(如适用) • 最大并发交易数量 • 止损百分比 • 滑点容忍度 • 最低流动性要求 示例:入场 = 6% 出场 = 2% 总收益 = 4% 净利润 = 点差 – 手续费 – 资金 ...
Expert Developer Wanted: Low-Latency Telegram Trading Bot for BTC/USDT (HFT/Scalping) Project Overview: I am looking for a senior blockchain/backend developer to build a high-performance Telegram-based trading bot specialized in BTC/USDT scalping. The bot must be optimized for speed, executing entries and exits almost instantaneously during peak volume hours. Core Functionality: Telegram Interface: Full control via Telegram (Start/Stop, Manual Override, Real-time P&L alerts). High-Speed Execution: Must use WebSockets (not REST) for sub-10ms data feeds. Volume-Based Logic: The bot must automatically trigger or increase activity during the 13:00–16:00 UTC window (or based on real-time volume spikes). Rapid Scalping Strategy: Automated "Sniper" entry and exit based o...
I am building out the core of a new product on the Solana blockchain and need a seasoned engineer to write, test, and deploy custom smart contracts. Your job is to translate a set of functional requirements into secure, efficient on-chain programs, then walk me through deployment and version control so I can maintain the codebase moving forward. The role is 100 % Solana focused, so I expect fluency with Rust, Anchor, the Solana CLI, and standard auditing tools. If you also enjoy crafting full dApps or connecting on-chain logic to existing back-end services, that will be useful down the line, but for this phase the deliverable is solely the smart contract layer. Deliverables – Well-documented Rust/Anchor smart contracts that satisfy the functional spec – Local and test-net d...
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