Quadratic Funding

Quadratic funding (QF) is a funding mechanism designed to allocate capital to projects based on how many unique people support them, not how much each person gives. It is the default mechanism for serious public goods funding in the Ethereum ecosystem, used by Gitcoin Grants, Giveth, and parts of Optimism's funding programs.

The Core Idea

Traditional crowdfunding rewards whoever has the most capital. If one person donates $10,000 and ten people each donate $100, the project with the whale receives more, even though the project with ten donors arguably has broader public value.

Quadratic funding inverts this. A matching pool layered on top of direct donations allocates additional funding based on unique-donor count, not total raised. The math treats the square root of each donation as the signal, then squares the summed signals to compute allocation. The practical effect:

• 100 donors × $5 each → significantly more matching than 5 donors × $100 each, even though raw totals are identical.
• Adding a new unique donor to a project provides much more matching benefit than increasing the donation from an existing donor.
• Broad support is treated as strong evidence of public value.

Why It Works for Public Goods

Public goods are underfunded by traditional markets because no single actor can capture the full benefit — everyone gains, but no one wants to pay for the whole thing. QF solves this by rewarding the act of showing up, not the size of the check. If a project benefits many people, and many people are willing to chip in a small amount to support it, the matching pool amplifies that signal into real funding.

This is particularly effective for:

• Open source infrastructure
• Security research
• Developer education
• Client implementations
• Community tools

Who Uses It

• Gitcoin Grants — quarterly QF rounds for open source projects since 2019.
• Giveth — ongoing QF rounds, including the Ethereum Security round backed by TheDAO Security Fund.
• Optimism RetroPGF — retroactive variant where projects are funded after demonstrating impact (not strictly QF, but related public-goods-funding mechanism).
• Various protocol-specific programs — many DAOs run QF-style funding for ecosystem grants.

Sybil Resistance Is Critical

The biggest vulnerability in QF is sybil farming — a single attacker creating many wallets to manufacture fake "unique donor" signal. Every serious QF round defends against this with:

• Gitcoin Passport or similar proof-of-personhood scores
• Statistical analysis of donation patterns
• Wallet clustering and funding-source analysis
• Minimum donation amounts to make farming uneconomical

The Ethereum Security QF round operated by Giveth adds an additional layer: ETHSecurity Badge holders get ~2x matching impact, amplifying trusted expert voices on top of the base Passport verification.

QF vs Traditional Grants

Both mechanisms have their place. QF is unique in letting the community's aggregate signal determine allocation, which is valuable when no single committee has the breadth of context to evaluate dozens of distinct projects.

Further Reading

The clearest explainer for the underlying math is wtfisqf.com. For a practical walkthrough of participating in a current round, see the Ethereum Security QF round article.