---
title: "Inside Ethereum Protocol Fellowship: Every Project from Cohort 5 & 6, Mapped"
tags:
- ethereum
- protocol
- EPF
- core-dev
- fellowship
- blockchain
- Rust
- consensus
- execution
- zkVM
- FOCIL
- PeerDAS
description: "A research-grade reference for EPF7 applicants, and anyone curious about what actually gets built at the frontier of Ethereum core development."
---

# Inside Ethereum Protocol Fellowship: Every Project from Cohort 5 & 6, Mapped

## Motivation

I'm applying for EPF Cohort 7. To prepare, I went deep on what was proposed, what was picked up, and what's still on the table. This document is the artifact of that research. If you're also applying or just want to understand where Ethereum protocol R&D is heading, this report is for you.

---

## What Is the Ethereum Protocol Fellowship?

The [Ethereum Protocol Fellowship (EPF)](https://github.com/eth-protocol-fellows/cohort-six/blob/master/program-guide/program-details.md) is a 5-month program that onboards engineers directly into core Ethereum protocol development. Fellows receive a monthly stipend, mentorship from core devs, and full autonomy to pick and execute a project that matters to the protocol.

This is not a bootcamp. There are no lectures. Mentors "open doors, not hold hands." The expectation is that you arrive technically capable, self-directed, and genuinely motivated to contribute to the public good.

> **EPF is arguably the single best on-ramp into Ethereum core development that exists today.**

---

## How to Read This Article

Each cohort section contains two things:

1. **A table of proposed projects** - ideas put forward by client teams and mentors (like from Prysm, Ream, Reth, Nethermind, Lighthouse and the rest..), tagged by whether a fellow actually picked them up
2. **A table of executed projects** - all project proposals actually submitted by fellows (some of these go beyond the official idea list)

**Status key:**
| Symbol | Meaning |
|--------|---------|
| ✅ | Executed by a fellow |
| ❌ | Proposed but not picked up |
| 🔁 | Partially addressed / overlapping scope |

---

## [Cohort 5 (EPF5)](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/project-ideas.md)

### Cohort 5 - Proposed Projects vs. Execution Status

| # | Proposed Project | Proposing Team | Status |
|---|-----------------|---------------|--------|
| 1 | Prysm: ePBS implementation | Prysm / @potuz, @terencechain | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/epbs-implementation-in-prysm.md) |
| 2 | Prysm: Custom Golang libp2p implementation | Prysm / @nisdas, @nalepae | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/Prysm_libP2P_Implementation.md) |
| 3 | Prysm: Light client server-side support | Prysm / @rkapka | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/light-client-support-in-prysm.md) |
| 4 | Ephemery testnet client integrations (EIP-6916) | Mario Havel | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/native-ephemery-client-pair-implementation.md) |
| 5 | JSON-RPC enhancements in Geth (trace_*, error codes) | Sina | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/jsonrpc-enhancements-in-geth.md) |
| 6 | Grandine: Separated Validator Client | Saulius Grigaitis | ❌ Not executed |
| 7 | Grandine: Embeddable Grandine (integrate into Geth, Nethermind, Besu, etc.) | Saulius Grigaitis | ❌ Not executed |
| 8 | Grandine: Performance profiling harness | Saulius Grigaitis | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/securing-grandines-performance.md) |
| 9 | Grandine: Performance improvements (CPU, memory) | Saulius Grigaitis | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/securing-grandines-performance.md) |
| 10 | Grandine: SSZ StableContainers (EIP-7495) | Saulius Grigaitis | ❌ Not executed |
| 11 | Grandine: Slasher refactor/optimization | Saulius Grigaitis | ❌ Not executed |
| 12 | Grandine: P2P stack improvements | Saulius Grigaitis | ❌ Not executed |
| 13 | Grandine: rust-kzg PeerDAS cryptography | Saulius Grigaitis | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/grandine-rust-kzg-library.md) |
| 14 | Grandine: Logging refactor (tracing) | Saulius Grigaitis | ❌ Not executed |
| 15 | Grandine: PeerDAS improvements | Saulius Grigaitis | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/peerdas-grandine.md) |
| 16 | Grandine: E2E testing (Hive/Kurtosis) | Saulius Grigaitis | ❌ Not executed |
| 17 | Grandine: Windows and macOS support | Saulius Grigaitis | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/grandine-windows-support.md) |
| 18 | Grandine: Redesign Rayon for lazy evaluation | Saulius Grigaitis | ❌ Not executed |
| 19 | Grandine: EIP-4881 deposit snapshot | Saulius Grigaitis | ❌ Removed from ideas |
| 20 | Grandine: Light client implementation | Saulius Grigaitis | ❌ Not executed |
| 21 | Grandine: Fuzzing integration | Saulius Grigaitis | ❌ Not executed |
| 22 | Grandine: Cross-client snapshot test adaptation | Saulius Grigaitis | ❌ Not executed |
| 23 | Grandine: Support documentation | Saulius Grigaitis | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/Grandine-Support-Documentation.md) |
| 24 | Lodestar: BeaconChain Harness for client testing | Lodestar Team | ❌ Not executed |
| 25 | Lodestar: Light clients research + implementation | Lodestar Team | ❌ Not executed |
| 26 | Ipsilon: Consensus-level ETH supply opcode | chfast, axic | ❌ Not executed |
| 27 | Ipsilon: EVM memory repricing | chfast, axic | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/evm-memory-repricing.md) |
| 28 | Ipsilon: EVM transfer functions design (PAY, TRANSFER) | chfast, axic | ❌ Not executed |
| 29 | Ipsilon: Formally verify EOF stack validation | chfast, axic | ❌ Not executed |
| 30 | Ipsilon: EVMMAX prototyping | chfast, axic | ❌ Not executed |
| 31 | Ipsilon: EOF research tooling (Huff, Remix, Foundry) | chfast, axic | ❌ Not executed |
| 32 | Protocol Security: Auditing/fuzzing (networking, crypto, clients) | Fredrik | ❌ Not executed |
| 33 | The Rated List DHT | Dankrad | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/enhanced-dht-proposal-with-rated-list-and-hierarchical-levels.md) |
| 34 | Nimbus: Extend KZG in Constantine for PeerDAS | Nimbus | ❌ Not executed |
| 35 | Nimbus: C bindings for Constantine | Nimbus | ❌ Not executed |
| 36 | Nimbus: Constantine as Nimbus cryptographic backend | Nimbus | ❌ Not executed |
| 37 | Nimbus: Fuzzing (SSZ, RLP, JSON-RPC, libp2p) | Nimbus | ❌ Not executed |
| 38 | Besu: Portal Client (Java, Dagger) | Besu | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/besu-portal-client.md) |
| 39 | Besu: PeerSpective peering visualization tool | Besu | ❌ Not executed |
| 40 | Besu: Archive mode with Bonsai storage | Besu | ❌ Not executed |
| 41 | Besu: SSZ transactions (EIP-6493) | Besu | ❌ Not executed |
| 42 | Trin: Portal Beacon network hive tests | Kolby ML | ❌ Not executed |
| 43 | Trin: Portal State network hive tests | Kolby ML | ❌ Not executed |
| 44 | Trin: Contribute to Trin Execution Client (non-devp2p) | Kolby ML | ❌ Not executed |
| 45 | Lighthouse: Network simulations with Shadow framework | Age Manning | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/network-simulations-with-shadow.md) |
| 46 | Lighthouse: Tracing integration | Lighthouse | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/tracing-integration-lighthouse.md) |
| 47 | Lighthouse: Improve common crates (types, eth2-types) | Lighthouse | ❌ Not executed |
| 48 | Lighthouse: Improve test coverage in validator client | Lighthouse | ❌ Not executed |
| 49 | PandaOps tooling wishlist items | Pari | ❌ Not executed |
| 50 | RIG Open Problems (mechanism design) | Barnabé Monnot | 🔁 [Partial](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/ssf-consensus-research.md) (SSF research) |

---

### Cohort 5 - All Executed Projects (Fellows' Proposals)

| # | Project Title | Client / Area | Notes |
|---|--------------|--------------|-------|
| 1 | [ePBS Implementation in Prysm](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/epbs-implementation-in-prysm.md) | Prysm | Full ePBS PoC in Go |
| 2 | [ePBS Implementation in Nimbus](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/epbs-implementation-in-nimbus.md) | Nimbus | Consensus client ePBS |
| 3 | [Prysm: Custom libp2p in Go](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/Prysm_libP2P_Implementation.md) | Prysm / Networking | In-house libp2p implementation |
| 4 | [Light Client Support in Prysm](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/light-client-support-in-prysm.md) | Prysm | Server-side light client infrastructure |
| 5 | [FOCIL PoC - Geth and Prysm](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/focil-geth-and-prysm-poc.md) | Geth + Prysm | EIP-7805 early implementation |
| 6 | [FOCIL PoC - Lighthouse and Reth](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/focil-lighthouse-and-reth-poc.md) | Lighthouse + Reth | Cross-client FOCIL PoC |
| 7 | [PeerDAS - Grandine](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/peerdas-grandine.md) | Grandine | PeerDAS implementation in Grandine |
| 8 | [PeerDAS - Nimbus CL](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/peerdas-nimbus.md) | Nimbus | PeerDAS in Nimbus consensus client |
| 9 | [PeerDAS Metrics & Specs](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/peerdas-metrics-specs.md) | Research / Metrics | Spec metrics and monitoring work |
| 10 | [Grandine rust-kzg Library](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/grandine-rust-kzg-library.md) | Grandine / Crypto | KZG cryptography library for Grandine |
| 11 | [Grandine: Securing Performance](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/securing-grandines-performance.md) | Grandine | CPU/memory profiling and optimizations |
| 12 | [Grandine: Windows Support](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/grandine-windows-support.md) | Grandine / DevEx | Cross-platform build and CI support |
| 13 | [Grandine: Support Documentation](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/Grandine-Support-Documentation.md) | Grandine | Developer-facing documentation |
| 14 | [JSON-RPC Enhancements in Geth](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/jsonrpc-enhancements-in-geth.md) | Geth / EL | trace_filter, error codes, benchmarking |
| 15 | [EVM Memory Repricing](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/evm-memory-repricing.md) | EVM / Ipsilon | Analysis and repricing proposal |
| 16 | [Reth: Verkle PoC](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/reth-verkle-poc.md) | Reth / State | Verkle trie integration into Reth |
| 17 | [SSF Consensus Research](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/ssf-consensus-research.md) | Research | Single Slot Finality research |
| 18 | [Native Ephemery Client Pair Implementation](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/native-ephemery-client-pair-implementation.md) | Ephemery | EIP-6916 testnet client integration |
| 19 | [Besu: Portal Client](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/besu-portal-client.md) | Besu / Portal | Java-based Portal Network client |
| 20 | [Samba: Java Portal Client](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/samba-a-java-portal-client.md) | Portal | Standalone Java Portal implementation |
| 21 | [Enhanced DHT with Rated List and Hierarchical Levels](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/enhanced-dht-proposal-with-rated-list-and-hierarchical-levels.md) | Networking / DHT | Prototyping rated DHT for P2P |
| 22 | [Network Simulations with Shadow](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/network-simulations-with-shadow.md) | Lighthouse / Networking | P2P network simulation via Shadow |
| 23 | [Tracing Integration in Lighthouse](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/tracing-integration-lighthouse.md) | Lighthouse | Tokio tracing and observability |
| 24 | [Axum Transition in Lighthouse](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/axum-transition-in-lighthouse.md) | Lighthouse | HTTP framework migration |
| 25 | [Attestation-Based Inclusion List](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/attestation-based-inclusion-list.md) | CL / Inclusion | EIP-7547-adjacent inclusion list research |
| 26 | [eODS Specification](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/eods-specification.md) | Research | External data storage specification |
| 27 | [Push-Based Custom Ceiling Partial Withdraw (EIP-7251 / MaxEB)](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/Push-Based-Custom-Ceiling-Partial-Withdraw-for-EIP7251-MaxEB.md) | CL / Staking | MaxEB partial withdrawal research |
| 28 | [Opcode Implementations, Test Coverage & Stats — IL EVM (Nethermind)](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/opcode-implementations-test-coverage-code-analysis-and-stats-il-evm-nethermind.md) | Nethermind / EVM | Interpreter-level EVM test coverage |
| 29 | [SSZ Benchmarking and Optimization](https://github.com/eth-protocol-fellows/cohort-five/blob/main/projects/ssz-benchmarking-and-optimization.md) | Cross-client / SSZ | SSZ performance work |

---

## [Cohort 6 (EPF6)](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/project-ideas.md)

### Cohort 6 - Proposed Projects vs. Execution Status

| # | Proposed Project | Proposing Team | Status |
|---|-----------------|---------------|--------|
| 1 | Lodestar: Backfill mechanism | Lodestar | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/lodestar-backfill.md) |
| 2 | Lodestar: ERA file support | Lodestar | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Era-file-support-for-lodestar.md) |
| 3 | Besu: discv5 support | Besu | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Implement-discv5-handling-in-Besu.md) |
| 4 | Besu: eth/70 implementation | Besu | ❌ Not executed |
| 5 | Besu: Ephemery support (remaining tasks) | Besu | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Ephemery-Besu-Implementation.md) |
| 6 | Teku/Nimbus/Grandine: EIP-7917 (deterministic proposer lookahead) | Justin Drake / Lin Oshitani | ❌ Not executed |
| 7 | Erigon: FOCIL (EIP-7805) & BRIAD research | Erigon | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/erigon_focil.md) |
| 8 | Erigon: Parallel Execution (Block STM, EIP-7928) | Erigon | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/erigon-parallel-execution.md) |
| 9 | Erigon: Parallel Embedded Indexing (map/reduce framework) | Erigon | ❌ Not executed |
| 10 | Erigon: RISCV Executable Proof Sourcing | Erigon | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/erigon_riscv_proof_sourcing.md) |
| 11 | Erigon: L1 Clearing Bridge (R&D, EIP-7702) | Erigon | ❌ Not executed |
| 12 | Ream: Build Beacon Validator Client | Ream / Kolby & Kayden | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/ream-validator-client.md) |
| 13 | Ream: Build out P2P testing | Ream | ❌ Not executed |
| 14 | Ream: Implement Beacon API Endpoints | Ream | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/ream-beacon-api.md) |
| 15 | Ream: Benchmark zkVM performance on beacon STFs | Ream / Unnawut | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/benchmarking_zkVMs_ream_dimitris.md) |
| 16 | Lighthouse: Checkpoint sync from non-finalized checkpoint | Lighthouse | ❌ Not executed |
| 17 | Lighthouse: Better state cache heuristics | Lighthouse | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Lighthouse_Better_State_Cache_Heuristics.md) |
| 18 | Lighthouse: PostgresDB as optional beacon node backend | Lighthouse | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/lighthouse_postgresdb_beacon_node_backend.md) |
| 19 | Grandine: FOCIL (EIP-7805) implementation | Grandine | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/FOCIL_For_Grandine.md) |
| 20 | Grandine: Optimizing PeerDAS for production | Grandine | 🔁 [Partial](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Rust_KZG%20_From_Education_to_PeerDAS_Production_Grade_Optimization.md) (Rust-KZG project) |
| 21 | Grandine: EL Client Integrations | Grandine | ❌ Not executed |
| 22 | Grandine: zkVMs for Beacon Chain snarkification | Grandine | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/grandine_beacon_zkVMs_snarkification.md) |
| 23 | Grandine: Disk Usage Optimization for state storage | Grandine | ❌ Not executed |
| 24 | Grandine: Tokio Tracing integration | Grandine | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Grandine-Implementing-Tokio-Tracing-For-Debugging-And-Performance-Analysis.md) |
| 25 | Grandine: Distributed Validator Technology (DVT) compatibility | Grandine | ❌ Not executed |
| 26 | Grandine: Standalone Validator Client | Grandine | ❌ Not executed |
| 27 | Grandine: ePBS (EIP-7732) | Grandine | ❌ Not executed |
| 28 | Grandine: Additional BLS backends | Grandine | ❌ Not executed |
| 29 | Grandine: Additional database backends (RocksDB, Sled) | Grandine | ❌ Not executed |
| 30 | Nimbus EL: era1/era/e2ss/e2hs file support | Nimbus | ❌ Not executed |
| 31 | Nimbus CL: FOCIL (EIP-7805) implementation | Nimbus | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/FOCIL_Nimbus_CL.md) |
| 32 | Nimbus CL: PeerDAS performance optimization | Nimbus / Agnish | ❌ Not executed |
| 33 | Nimbus EL: Discovery V5 support | Nimbus | ❌ Not executed |
| 34 | Pureth (EIP-7919) — any EL client | Etan Kissling / Nimbus | ✅ [Erigon](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/pureth-eip-7919-erigon.md) · [Nimbus](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/pureth-eip-7919-nimbus.md) · [Reth](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/reth-pureth-meta.md) |
| 35 | Prysm: Migrate e2e to Kurtosis + Assertoor | Prysm | 🔁 [Partial](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/lodestar-sim-tests-framework-to-kurtosis.md) (Lodestar sim-tests migration) |
| 36 | Prysm: Lazy Slasher | Prysm | ❌ Not executed |
| 37 | Prysm: SSZ Query Language | Prysm | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/ssz-ql-with-merkle-proofs.md) |
| 38 | Prysm: Merkle Proofs of Everything (generic SSZ proofs) | Prysm | 🔁 [Partial](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/ssz-ql-with-merkle-proofs.md) (SSZ-QL with proofs) |
| 39 | Implement Fast Confirmation Rule (any CL client) | EF Protocol Consensus Team | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Fast_Confirmation_Rule_Lighthouse.md) (Lighthouse) |
| 40 | Ephemery testnet (EIP-6916) integrations | Mario Havel | ✅ [Executed](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Ephemery-Besu-Implementation.md) |
| 41 | PandaOps tooling wishlist | Pari | ❌ Not executed |
| 42 | RIG Open Problems | Barnabé Monnot | ❌ Not explicitly executed |
| 43 | Protocol Security tooling wishlist | Fredrik | ❌ Not explicitly executed |

---

### [Cohort 6](https://ps.ethereum.foundation/blog/epf6-recap) - All Executed Projects (Fellows' Proposals)

| # | Project Title | Client / Area | Notes |
|---|--------------|--------------|-------|
| 1 | [Ephemery - Besu Implementation](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Ephemery-Besu-Implementation.md) | Besu / Ephemery | EIP-6916 Besu integration |
| 2 | [ERA File Support for Lodestar](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Era-file-support-for-lodestar.md) | Lodestar / History | Historical state via ERA files |
| 3 | [FOCIL for Grandine](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/FOCIL_For_Grandine.md) | Grandine / CL | EIP-7805 censorship resistance |
| 4 | [FOCIL for Nimbus CL](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/FOCIL_Nimbus_CL.md) | Nimbus / CL | EIP-7805 implementation |
| 5 | [Fast Confirmation Rule - Lighthouse](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Fast_Confirmation_Rule_Lighthouse.md) | Lighthouse / CL | 1–2 slot pre-finality confirmation |
| 6 | [Grandine: Tokio Tracing Integration](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Grandine-Implementing-Tokio-Tracing-For-Debugging-And-Performance-Analysis.md) | Grandine / Observability | Structured async logging/profiling |
| 7 | [Implement discv5 in Besu](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Implement-discv5-handling-in-Besu.md) | Besu / Networking | EL peer discovery via discv5 |
| 8 | [Lighthouse: Better State Cache Heuristics](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Lighthouse_Better_State_Cache_Heuristics.md) | Lighthouse / CL | Dynamic state cache sizing |
| 9 | [Rust-KZG - From Education to PeerDAS Production-Grade Optimization](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/Rust_KZG%20_From_Education_to_PeerDAS_Production_Grade_Optimization.md) | Grandine / Crypto | KZG optimization for PeerDAS |
| 10 | [Benchmarking zkVMs on Ream Beacon STFs](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/benchmarking_zkVMs_ream_dimitris.md) | Ream / zkVM | SP1, RISC Zero, OpenVM, Zisk benchmarks |
| 11 | [Block-Level Access Lists in Reth](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/block-level-access-lists-in-reth.md) | Reth / EL | EIP-7928 access list research + impl |
| 12 | [Differential LLMing](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/differential-llming.md) | Research / Tooling | LLM-assisted differential testing |
| 13 | [eODS PoC](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/eODS-POC.md) | Research | External data storage PoC |
| 14 | [EF zkEVM Research](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/ef-zkEVM-research.md) | Research / zkEVM | zkEVM formalization and research |
| 15 | [Erigon: Parallel Execution](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/erigon-parallel-execution.md) | Erigon / EL | Block STM parallel EVM execution |
| 16 | [Erigon: FOCIL](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/erigon_focil.md) | Erigon / CL + EL | EIP-7805 implementation in Erigon |
| 17 | [Erigon: RISCV Proof Sourcing](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/erigon_riscv_proof_sourcing.md) | Erigon / ZK | ISA transpilation for zkVM proving |
| 18 | [FOCIL - Reth](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/focil-reth.md) | Reth / EL | EIP-7805 implementation in Reth |
| 19 | [Grandine: Beacon Chain zkVM Snarkification](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/grandine_beacon_zkVMs_snarkification.md) | Grandine / ZK | Beacon state transition SNARK proving |
| 20 | [Lighthouse: ePBS](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/lighthouse_epbs.md) | Lighthouse / CL | EIP-7732 ePBS implementation |
| 21 | [Lighthouse: PostgresDB Beacon Node Backend](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/lighthouse_postgresdb_beacon_node_backend.md) | Lighthouse / Storage | NFS-safe database backend |
| 22 | [Lodestar: Backfill](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/lodestar-backfill.md) | Lodestar / Sync | Block/blob/custody backfill sync |
| 23 | [Lodestar: Sim Tests Framework → Kurtosis](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/lodestar-sim-tests-framework-to-kurtosis.md) | Lodestar / Testing | E2E test infrastructure migration |
| 24 | [Pureth (EIP-7919) - Erigon](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/pureth-eip-7919-erigon.md) | Erigon / RPC | Verifiable JSON-RPC with proofs |
| 25 | [Pureth (EIP-7919) - Nimbus](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/pureth-eip-7919-nimbus.md) | Nimbus / RPC | Verifiable JSON-RPC with proofs |
| 26 | [Ream: Beacon API Implementation](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/ream-beacon-api.md) | Ream / CL | REST API for Ream consensus client |
| 27 | [Ream: Validator Client](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/ream-validator-client.md) | Ream / CL | Beacon validator client for Ream |
| 28 | [Reth: Pureth Meta](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/reth-pureth-meta.md) | Reth / RPC | Pureth EIP-7919 coordination on Reth |
| 29 | [SSZ Query Language with Merkle Proofs](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/ssz-ql-with-merkle-proofs.md) | Research / SSZ | Generic SSZ querying + proof generation |
| 30 | [Zig libp2p: QUIC + Gossipsub](https://github.com/eth-protocol-fellows/cohort-six/blob/master/projects/zig-libp2p-QUIC+Gossipsub.md) | Networking / Zig | libp2p stack implemented in Zig |

---

## Cross-Cohort Analysis: What Patterns Emerge?

### Areas That Attract Fellows Consistently

| Theme | C5 Coverage | C6 Coverage | Still Open? |
|-------|-------------|-------------|-------------|
| FOCIL / Censorship Resistance | ✅ PoC in Geth+Prysm, Lighthouse+Reth | ✅ Grandine, Nimbus, Erigon, Reth | 🔁 More clients possible |
| ePBS (EIP-7732) | ✅ Prysm, Nimbus | ✅ Lighthouse | ❌ Grandine ePBS still open |
| PeerDAS / KZG | ✅ Grandine, Nimbus | ✅ Rust-KZG | 🔁 Optimization ongoing |
| zkVM / SNARKification | — | ✅ Ream benchmarks, Grandine SNARKs | 🔁 Expanding scope |
| Pureth / Verifiable RPC | — | ✅ Erigon, Nimbus, Reth | ❌ More EL clients open |
| Portal Network | ✅ Besu, Samba | — | ❌ Still open |
| Ephemery testnet | ✅ Native client pair | ✅ Besu integration | 🔁 More clients open |
| discv5 | — | ✅ Besu | ❌ Nimbus EL open |
| Prysm SSZ tooling | — | ✅ SSZ-QL + Merkle Proofs | ❌ More work possible |
| Fast Confirmation Rule | — | ✅ Lighthouse | ❌ Other clients open |

### Ideas That Haven't Been Picked Up (Across Both Cohorts)

These are potentially high-value areas for an EPF7 proposal that you might see:

| Idea | Originally Proposed | Why It Might Be Compelling |
|------|--------------------|-----------------------------|
| Grandine: ePBS (EIP-7732) | C6 / Grandine | ePBS has active spec work; multiple clients implementing |
| Grandine: Standalone Validator Client | C5 + C6 / Grandine | Architectural gap; mentioned in both cohorts |
| Nimbus EL: Discovery V5 | C6 / Nimbus | discv5 alignment between CL and EL codebases |
| Nimbus EL: era/e2ss/e2hs file support | C6 / Nimbus | Important for historical data access |
| Teku/Nimbus: EIP-7917 proposer lookahead | C6 / Justin Drake | Deterministic lookahead; relatively scoped |
| Besu: eth/70 | C6 / Besu | New EL wire protocol; well-scoped |
| Prysm: Lazy Slasher | C6 / Prysm | Slashing protection improvement with existing tracking issue |
| Lighthouse: Non-finalized checkpoint sync | C6 / Lighthouse | Critical for long non-finality scenarios |
| Grandine: DVT Compatibility | C6 / Grandine | DVT is gaining momentum; Grandine has a gap here |
| Grandine: Additional DB backends | C6 / Grandine | libmdbx is the only backend currently |
| EOF tooling (Foundry, Remix, debugger) | C5 / Ipsilon | EOF is shipping; tooling lags behind |
| Nimbus: Constantine as cryptographic backend | C5 / Nimbus | Cross-client cryptographic library alignment |
| Protocol Security fuzzing (networking, clients) | C5 / Fredrik | Security wishlist is open-ended and valuable |

---

<!-- ## What Should an EPF7 Fellow Build?

Here are some observations from mapping all of this:

**1. FOCIL is mature enough - look for the next censorship-resistance primitive.**
FOCIL (EIP-7805) has been implemented across Grandine, Nimbus, Erigon, Reth, and partially in Lighthouse/Geth. EPF7 might see BRIAD alternatives, or FOCIL production hardening rather than PoC work.

**2. zkVM snarkification is the new frontier.**
From Ream's multi-zkVM benchmarking to Grandine's Beacon state SNARKs, this area is rapidly expanding. EPF7 will likely see more coverage of OpenVM, Zisk, Jolt, and Beam Chain alignment.

**3. The Pureth (EIP-7919) wave isn't done.**
Verifiable JSON-RPC with proofs was implemented on Erigon, Nimbus, and Reth in C6. Geth, Nethermind, and Besu are open territory.

**4. Zig in Ethereum protocol infrastructure is emerging.**
The Zig libp2p project (QUIC + Gossipsub) in C6 signals growing interest in systems-level alternatives. This is an unusual niche with strong differentiation potential.

**5. Rust is the dominant implementation language for new protocol work.**
Reth, Ream, Grandine, and various research projects are all Rust-first. If you're a Rust engineer, you have clear entry points.

**6. Don't underestimate research-oriented proposals.**
eODS specification, SSF consensus research, and differential LLMing all found homes in EPF. If you have a strong research angle, that path is available.
-->
<!-- --- -->

## 📎 Resources to Go Deeper

| Resource | Link |
|----------|------|
| EPF6 Project Directory | [github.com/eth-protocol-fellows/cohort-six/projects](https://github.com/eth-protocol-fellows/cohort-six/tree/main/projects) |
| EPF5 Project Directory | [github.com/eth-protocol-fellows/cohort-five/projects](https://github.com/eth-protocol-fellows/cohort-five/tree/main/projects) |
| EPF Wiki | [epf.wiki](https://epf.wiki), [study epf wiki](https://study.epf.wiki/) |
| Ethereum Protocol Fellowship Info | [github.com/eth-protocol-fellows](https://github.com/eth-protocol-fellows) |
| PandaOps Tooling Wishlist | [github.com/ethpandaops/tooling-wishlist](https://github.com/ethpandaops/tooling-wishlist) |
| Protocol Security Wishlist | [security.ethereum.org/wishlist](https://security.ethereum.org/wishlist) |
| RIG Open Problems | [efdn.notion.site/ROPs](https://efdn.notion.site/ROPs-RIG-Open-Problems-c11382c213f949a4b89927ef4e962adf) |
| Ephemery Resources | [github.com/ephemery-testnet/ephemery-resources](https://github.com/ephemery-testnet/ephemery-resources) |
| Fast Confirmation Rule Spec | [github.com/mkalinin/confirmation-rule](https://github.com/mkalinin/confirmation-rule) |

---

## Closing Thoughts

The Ethereum Protocol Fellowship is one of the few programs in the world where you can spend five months working on infrastructure that billions of dollars of value flows through daily and that has a real shot at getting merged upstream.

What this analysis shows is that the idea list is always larger than what any single cohort can execute. That's not a flaw, it's an opportunity. Many of the projects listed as ❌ Not executed aren't dead ends; they're open doors.

If you're applying to EPF7, use this table to find the gaps. Then go read the relevant GitHub issues, understand why the gap exists, and write a proposal that convincingly addresses it.

Good luck. See you in the protocol guys.
___

This article was compiled for EPF7 research purposes. All project data sourced from the EPF GitHub repository (cohort-five and cohort-six). Always give the EPF teams credits they deserved.