Implementations

The following table lists current EIP-7916 / EIP-7495 / EIP-8016 implementation efforts. Note that implementations are not complete, and specifications may still change.

Language	Library	Implementer	Progress
C#	Nethermind	open
Go	dynssz	@pk910	M4
Go	Erigon (1 2 3)	@DarkLord017
Go	FastSSZ	open
Go	karalabe/ssz	open
Go	methodical-ssz	open
Java	Teku	open
Nim	nim-ssz-serialization	@etan-status	M4
Python	remerkleable	@etan-status	M4
Rust	ethereum_ssz	@SkandaBhat
Rust	Grandine	open
TypeScript	micro-eth-signer	open
Zig	ChainSafe	@guha-rahul
Zig	ssz.zig	open

Specs

ethereum/consensus-specs defines all SSZ specifications.

Tests

ethereum/remerkleable contains static tests in test_impl.py and test_typing.py.
ethereum/consensus-specs releases contain random tests in tests/general/phase0/ssz_generic, generated according to a format.

M1 - ProgressiveList

EIP-7916 introduces ProgressiveList[type] and ProgressiveBitlist. The bitlist can be deferred, as EIP-7745 only requires ProgressiveList[type] for bytes.

Tests

In test_impl.py and test_typing.py: Look for ProgressiveList.
In tests/general/phase0/ssz_generic: Look for basic_progressive_list, and for ProgressiveTestStruct in the containers category.

M2 - ProgressiveBitlist

Complete implementation of EIP-7916, including ProgressiveBitlist. The bitlist follows a similar Merkle tree shape as the regular list, but uses a slightly different encoding and code path.

Tests

In test_impl.py and test_typing.py: Look for ProgressiveBitlist.
In tests/general/phase0/ssz_generic: Look for progressive_bitlist, and for ProgressiveBitsStruct in the containers category.

M3 - ProgressiveContainer

EIP-7495 introduces ProgressiveContainer, which is relevant for EIP-6404 transaction and receipts EIPs.

Tests

In test_impl.py and test_typing.py: Look for ProgressiveContainer.
In tests/general/phase0/ssz_generic: Look for progressive_containers.

M4 - CompatibleUnion

EIP-8016 introduces CompatibleUnion, the final piece to implement all EIP-7919 Pureth components.

Tests

In test_impl.py and test_typing.py: Look for CompatibleUnion.
In tests/general/phase0/ssz_generic: Look for compatible_unions.

M5 - Optimizations

Optimized overloads of the data structures may be necessary, e.g., with additional caches. While not strictly required for the initial implementation, they should still eventually be implemented. As optimizations are implementation specific, there are no formal completion criteria.