The Ethereum Foundation opened applications on September 1, 2022 for the third cohort of its Ethereum Protocol Fellowship, a four-month program designed to bring new engineers into the protocol's core development layer. Applications closed September 16, with the cohort running from October 2022 through January or February 2023. The program is the third iteration of an evolving initiative previously known as the Core Developer Apprenticeship Program (CDAP).

The program paired selected developers with active core contributors and offered individualized stipends, aiming to lower the barriers that have historically kept the protocol's inner workings accessible to only a narrow pool of insiders.

The announcement came 14 days before The Merge, Ethereum's transition from proof-of-work to proof-of-stake that completed on September 15, 2022. That upgrade cut the network's energy consumption by more than 99% and opened a significantly more complex development roadmap. The timing was notable, underscoring a broader need for protocol-level engineering capacity.

More than 600 applications arrived for 23 funded positions, a selection rate of roughly 3.8%. An additional 13 contributors joined without stipends through what the program calls permissionless participation, meaning anyone could work on protocol projects and build a track record without waiting for formal selection.

The full cohort reached 36 contributors supported by 27 mentors drawn from teams across the Ethereum client ecosystem. By the conclusion of the program, participants had published more than 300 weekly progress updates across 20 projects.

The Ethereum Foundation's Protocol Support team described the program's purpose plainly in the announcement: "The intention of this program is to provide an easier onramp for getting past these barriers, and to provide the initial support and guidance to launch you into working side by side with core devs." Projects tackled during the cohort reflected the live development priorities of that period. Fellows contributed to EIP-4337, the account abstraction proposal, with work including a bundler implementation in Rust and wallet development. Others worked on EIP-4844, the proto-danksharding upgrade. Additional projects included Portal Network ultralight client development, Verkle Trie migration research, censorship resistance monitoring, and work on validator security and MEV (maximal extractable value, the profit validators can capture by reordering transactions).

Outcomes from the cohort supported the program's core premise. Across all cohorts at the time of the third cohort's recap, 10 EPF alumni had moved into full-time core protocol roles and five more had joined adjacent industry positions.

The permissionless track carried particular significance: it allowed developers to build verifiable protocol contributions and relationships with core teams without navigating the formal application and stipend process.

That design choice has direct relevance beyond the United States and Western Europe. Electric Capital's 2023 developer data shows that 72% of all crypto developers are located outside North America, and West Africa and South Asia rank among the fastest-growing regions for crypto developer share.

However, this growth is concentrated almost entirely at the application layer, covering DeFi protocols, NFT tooling, and wallets. Protocol-level contributors from Lagos, Nairobi, Karachi, or Bangalore remain a statistical rarity. The EPF is one of the few structured programs offering mentorship access from teams such as Lighthouse, Geth, Nethermind, and Ethereum Foundation Research to developers regardless of geography.

The permissionless participation model matters in another practical way. Developers in several Sub-Saharan African countries and parts of South Asia face reported friction with international payment infrastructure.

Being able to contribute, build a track record, and communicate directly with core developers does not require receiving a wire transfer. For regions where that friction is real, the unpaid track is a meaningful entry point into protocol-level work.

One unresolved concern is stipend transparency. The EPF negotiates compensation individually with each accepted applicant rather than publishing a standardized amount. That approach makes it difficult for developers in lower-income countries to assess whether participation is financially viable before investing time in an application. Publishing clearer guidance on stipend ranges and clarifying whether PPP-adjusted stipends could be made available would improve accessibility.

The program has continued well past the third cohort. The Ethereum Foundation announced Cohort 6 in April 2025. Cohort 5 attracted more than 300 applications and produced 30 active fellows mentored by teams including Geth, Lighthouse, Nethermind, Besu, Prysm, Teku, Nimbus, Reth, Grandine, and Ethereum Foundation Research.

As of 2023, Ethereum consistently attracted more than 8,000 monthly active contributors to its codebase and held the largest developer share of any blockchain on every continent, including Africa.

The EPF has become one of the few structured mechanisms for translating that broad interest into protocol-level capacity.