Crypto crowdfunding uses smart contracts to collect money from many backers, hold it, and release it or refund it under rules set before the raise starts. This guide explains the funding models, the contracts and parts of a crypto crowdfunding platform, the build steps, and the US and EU rules that apply when backers expect a return.
Three types of crypto crowdfunding
The type of raise decides the legal position of the platform, and the table compares the three types.
| Type | What backers get | Typical onchain form | Main legal concern |
|---|---|---|---|
| Donation and public goods | Nothing, or public recognition | Grant rounds, quadratic funding | Charity and tax rules in some countries |
| Reward-based | A product, access or an NFT | Escrowed pledges with NFT receipts | Consumer protection and pre-sale rules |
| Investment-based | Tokens, equity or a revenue share | Token sale or tokenized shares | Securities law in most countries |
A donation platform changes its legal position when it starts to give backers tokens with an expected return, and it then needs the licenses described in the regulation section below.
How DeFi crowdfunding contracts work
DeFi crowdfunding replaces the platform's bank account with a contract that anyone can inspect. Four funding models are in common use.
All-or-nothing escrow
Backers send funds to a campaign contract that stores a goal and a deadline. If the campaign reaches the goal by the deadline, the creator can withdraw the funds. If the campaign misses the goal, each backer calls a refund function and gets the contribution back.
Refunds should use a pull pattern, where each backer claims a refund in a separate transaction. A single function that refunds every backer in one loop can need more gas than a block allows, so it always fails and the funds stay locked in the contract.
Refunds also cost gas. ConstitutionDAO raised about $47 million in ether through the Juicebox protocol in November 2021 to bid on a copy of the US Constitution. The group lost the auction, and backers could reclaim their share minus the gas fees for the refund transaction. Small backers lost a large share of their contributions to those fees. A campaign on a layer 2 network or a low-fee chain reduces this cost.
Milestone-based release
A milestone contract releases the funds in tranches, and the creator receives each tranche after a milestone is confirmed. The confirmation can come from a backer vote weighted by contribution, from an appointed reviewer, or from both.
Backers can also hold a vote to cancel the remaining tranches and take back the unspent funds. Each vote needs a quorum and a time limit, because without a time limit a campaign can stay frozen when too few backers vote.
Quadratic funding
Quadratic funding splits a matching pool among public goods projects. To compute a project's match, the formula takes the square root of each donation, adds the results, and squares the total. As a result, many small donors unlock more matching money than one large donor who gives the same total.
Gitcoin made the model common on Ethereum. Its GG24 round ran from October to November 2025 and distributed more than $1.8 million across six funding areas. The weak point of quadratic funding is a Sybil attack, where one person splits money across many wallets to look like many donors.
In Gitcoin's GG24 rounds, donors had to pass a Human Passport check, and only donations above $1 counted toward matching. Human Passport is an identity scoring tool that began as Gitcoin Passport and now belongs to the Holonym Foundation. GG24 also used a matching formula called COCM, which gives less matching to groups of donors who give to the same projects together.
Streaming and retroactive funding
A streaming contract pays a project a continuous flow of tokens, and the funder can stop the flow at any time. Retroactive funding pays for work after it has proved useful, and Optimism's Retro Funding program uses this model for projects that build on its network. Both models move risk away from backers and suit ongoing open-source work.
Parts of a crypto crowdfunding platform
- Campaign factory. A factory contract deploys one contract per campaign with fixed terms, so a creator cannot change the terms after backers commit.
- Accepted assets. A goal set in a stablecoin keeps its value, while a goal set in a volatile token can be met or missed by price moves alone.
- Backer receipts. ERC-721 or ERC-1155 tokens record each contribution and can carry reward tiers. The NFT minting platform guide covers the minting side.
- Creator verification. KYC or a verified public identity for creators reduces rug pulls, where a creator takes the funds and disappears.
- Sybil resistance. Donation platforms with matching pools need an identity or reputation check such as a proof-of-personhood score.
- Governance module. This contract runs milestone votes, cancel votes and disputes.
- Indexer and front end. An indexer reads contract events, and the front end shows campaign pages, search and backer dashboards.
How to build a crypto crowdfunding platform
- Fix the funding type and the target countries with a lawyer, because the type decides the licenses.
- Write the campaign rules. Set the goal, deadline, release schedule, refund conditions and platform fee.
- Write and test the contracts for escrow, refunds and votes. Tests should cover edge cases, for example a deadline that passes during a milestone vote.
- Audit the contracts. The contracts hold pooled user funds, so they need the same smart contract audit as any DeFi protocol.
- Launch with curated campaigns before you open the platform to any creator. A curated launch lets the operator test the fraud controls on a small set of campaigns.
A small team can build a reward or donation platform in a few months, but an investment platform takes longer, mainly because of licensing and compliance work. If the platform is a token sale venue, the launchpad development guide and the ICO development guide cover that model.
Crypto crowdfunding regulation
Investment crowdfunding is regulated in the US and the EU, and a smart contract does not remove these rules.
| Rule | Who it covers | Key limits and duties |
|---|---|---|
| US Regulation Crowdfunding (SEC) | Companies that sell securities to the public online | Up to $5 million in 12 months. Sales must run through an SEC-registered funding portal or broker-dealer. The issuer files Form C. |
| EU Crowdfunding Service Providers Regulation (2020/1503) | Investment-based and lending-based platforms | The platform needs an authorization from one EU country, and that authorization is valid in every EU country. A project owner can raise up to €5 million in 12 months. |
| EU MiCA | Offers of crypto-assets that are not financial instruments | The offeror publishes a crypto-asset white paper, with exemptions for small offers. |
Under Regulation Crowdfunding, an investor who is not accredited faces a 12-month limit. If either annual income or net worth is below $124,000, the limit is the greater of $2,500 or 5% of the larger figure. If both income and net worth are at least $124,000, the limit is 10% of the larger figure, up to $124,000. The SEC set these numbers in its 2022 inflation adjustment.
The EU crowdfunding regulation has applied since November 10, 2021. Its transition period ended on November 10, 2023, so every investment or lending platform in the EU now needs the authorization. A token that promises a return is usually a security in the US and a financial instrument in the EU, where securities law covers it rather than MiCA.
Frequently asked questions
What is crypto crowdfunding?
Crypto crowdfunding raises money from many backers in cryptocurrency or stablecoins. A smart contract holds the funds and releases them to the creator or refunds them to backers under rules set before the raise.
Can backers get refunds automatically?
Yes, if the contract contains the refund conditions. In an all-or-nothing campaign, each backer can claim a refund after a missed deadline without permission from the creator. The backer still pays the gas fee for the refund transaction.
How does a crypto crowdfunding platform stop creators from taking the money?
Milestone releases, creator verification and backer votes to cancel the remaining tranches reduce the risk, but they cannot recover funds that the contract has already released.
Is quadratic funding suitable for investment raises?
No. Quadratic funding splits a matching pool among public goods projects. It does not price an investment or give backers a return.
Do I need a license to run a DeFi crowdfunding platform?
A platform for investment or lending raises needs a license in the US and the EU. In the US the operator registers as a funding portal or broker-dealer. In the EU the operator needs an authorization under the crowdfunding regulation. Donation and reward platforms usually need no securities license, but consumer and tax rules still apply.