PresaleWidget — Owner-Managed EVM Presale/ICO Flow

Contract Reference: EVMPresaleWidget
License: MIT
Solidity Version: ^0.8.x
Verified on Etherscan: September 3, 2025

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PresaleWidget is a lightweight, embeddable purchase flow for token presales and ICOs on any EVM-compatible chain.

Drop the widget into your website or dApp, configure your sale parameters, and let users contribute using native currency or approved ERC-20 tokens.

The UI is fast, responsive, fully brandable, and designed for maximum clarity — reducing friction and boosting conversion.

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What This Contract Implements

Feature	Description
Initialization	initializePresale(decimals, totalTokensforSale, rate, saleStatus) — sets token precision, total sale inventory, native-currency price (in smallest units), and whether the sale starts active.
Start/Stop Controls	activatePresale() and haltPresale() — toggle saleStatus on/off with owner-only access.
Accepted Assets & Pricing	Owner can:• Whitelist ERC-20s via registerPayableTokens(tokens, prices)• Toggle with updatePayableTokenStatus(token, status)• Adjust pricing via adjustTokenPricing(tokens, prices, rate)
Quoting Logic	calculateTokenAmount(token, amount) returns sale-token output using:amount * 10^saleTokenDec / priceWhere price is rate (native) or tokenPrices[token] (ERC-20), both in payer asset’s smallest units per 1 sale token.
Purchases	purchaseTokens(token, amount):• Forwards funds to owner immediately• Enforces inventory cap (totalTokensSold + out ≤ totalTokensforSale)• Tracks unique buyers• Accumulates purchased amounts per user
Owner Withdrawals	• withdraw(token, amt)• withdrawAll(token)• withdrawCurrency(amt) — for native ETH/BNB/etc.
Buyer Registry	getBuyersList(from, to) — returns paginated list of buyers and their purchased amounts

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Scope & Recommended Extensions

This reference contract delivers a simple, owner-managed sale with:

• Capped inventory
• Flexible payment options
• Full control over pricing and tokens

Does NOT include (by design):

• Allowlists
• Per-wallet limits
• Soft-cap refunds
• On-chain vesting/claims

Production-Ready Extensions (Recommended)

Module	Purpose
Vesting/Claims Contract	Cliffs + linear schedules, callable by buyers post-sale
Allowlist & Tier Module	Private rounds, KYC tiers, wallet caps
Soft-Cap & Refund Logic	Refund contributors if goal not met

The frontend widget is built to integrate seamlessly — just provide the ABI and contract address, and it auto-exposes claim buttons, round status, and user eligibility without touching the core sale logic.

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Frontend & Developer Experience

Tech Stack

• Frontend: Node.js + React.js (modern hooks)
• On-Chain: Solidity ^0.8.x

Wallet Support

• MetaMask
• WalletConnect
• Coinbase Wallet

Customization

• Theming: Light / Dark modes + full CSS variable override
• Branding: Custom logos, colors, fonts
• i18n: Fully localizable copy (JSON-based)

Documentation Included

• End-to-end setup guide
• RPC & ABI wiring
• Pricing configuration examples
• ERC-20 approval flow
• Integration patterns for vesting, allowlists, and refunds

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Operational Notes

Note	Detail
Fund Flow	All funds (native & ERC-20) are forwarded to owner on purchase — contract holds zero balance
ERC-20 Payments	Users must approve the contract before calling purchaseTokens()
Pricing Precision	rate and tokenPrices must be in payer’s smallest units per 1 sale token (with saleTokenDec decimals)
Security	Audit and test thoroughly when composing with vesting/refund modules

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In Short

PresaleWidget = Clear UX + Auditable Core + Full Owner Control

Launch faster. Stay flexible. Extend securely.

Embed. Configure. Sell. Claim. Done.

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Built for speed. Designed for trust. Ready for production.