A decentralized, permissionless, public Proof-of-Stake L1 with full EVM compatibility. Anyone with enough stake can validate; anyone can hold and send the native coin Gemba (GMB). No central operator decides who participates.
GMB is a utility coin: value comes from use (cheaper service access, workplace access control, event tickets, employee perks), not speculation. The long-term goal is infrastructure owned and run by the institutions and community that use it, where every participant follows the same on-chain rules and no one, including the founder or a municipality, holds special power.
The single source of truth for the design is CLAUDE.md. If a
design decision changes, update CLAUDE.md first, then the docs, then the code.
GembaBlockchain testnet (EVM chainId 821207) is listed in two official, community-run open-source chain registries — both pull requests merged:
- ethereum-lists/chains #8413 — the canonical registry of EVM networks that powers chainlist.org. Listing means wallets and developer tooling that read this registry recognise the network, and anyone can add it to MetaMask in one click from chainlist.org.
- blockscout/chainscout #241 — Blockscout's public directory of chains, listing the GembaScan testnet explorer (testnet.gembascan.io).
These are testnet listings (chainId 821207). Mainnet (chainId 821206) is not yet launched — it gets its own registry entries once the mainnet RPC/explorer are live.
| Field | Value |
|---|---|
| Network | GembaBlockchain |
| Native coin | Gemba (GMB), the staking and gas coin |
| Framework | Cosmos SDK + Cosmos EVM (cosmos/evm, evmd) on CometBFT |
| Consensus | CometBFT BFT PoS, instant finality (~2s), no reorgs |
| Cosmos chain-id | gemba-1 |
| EVM chainId | 821206 (EIP-155; separate from the Cosmos chain-id) |
| Accounts | eth_secp256k1, SLIP-0044 coin type 60, standard 0x addresses (MetaMask works) |
| Total supply | Fixed, minted once at genesis, never again (0% inflation) |
| Fees | Real GMB fees (EIP-1559); low but non-zero, scaling with usage |
| License | Code: Apache-2.0; docs: CC BY-SA 4.0 |
chain/ Cosmos EVM app (Go): genesis, node config, devnet scripts, custom modules
contracts/ Solidity (Foundry): governor, treasuries, NFTs, paymaster
services/ Node.js/Express backends (on-ramp, access-control API, indexers)
frontend/ React
explorer/ Blockscout docker setup ("GembaScan")
docs/ Detailed specs and runbooks (start with docs/risks.md)
The project is built in phases (see CLAUDE.md §13).
- Phase 0, Scaffolding: complete. Monorepo structure, secret hygiene, risk register.
- Phase 1, Local devnet: complete. Single-node and 4-validator devnets built from
the pinned upstream
cosmos/evmevmd(v0.7.0), with GembaBlockchain's economics baked into genesis (zero inflation, a non-zero gas-price floor, EVM chainId 821206, ~2s blocks, the fixed 100M GMB allocation). Verified end to end: MetaMask connection, a GMB transfer, a Solidity deploy, and 4-validator BFT liveness with one validator down. Seechain/scripts. - Phase 2, Custom chain modules: next. The validator reward streamer, the 60/40 fee split, and the post-reserve tail reward, all zero-inflation (no minting).
Live test network. The GembaBlockchain test network is up and working end to
end — producing ~2 s blocks, serving EVM JSON-RPC, accepting MetaMask, and the
first GMB transfer has been made and is indexed in GembaScan (the self-hosted
Blockscout explorer). This is the valueless dress-rehearsal testnet (gemba-testnet-1,
EVM chainId 821207), not mainnet — public launch is still gated by the blockers
below. Details and the first-transaction record: docs/testnet-status.md.
Prerequisites: Go (the version pinned in the upstream cosmos/evm go.mod), a C
compiler (for CGO), jq, and Foundry for the
transfer/deploy demos.
# 1. Build the pinned node binary once.
git clone --branch v0.7.0 https://github.com/cosmos/evm
cd evm && make install # installs evmd to $(go env GOPATH)/bin
export PATH="$PATH:$(go env GOPATH)/bin"
# 2. Single-node devnet.
cd /path/to/GembaBlockchain
./chain/scripts/init-single-node.sh
./chain/scripts/start-single-node.sh
# 3. Or a 4-validator BFT devnet (tolerates one validator down).
./chain/scripts/init-multinode.sh
./chain/scripts/start-multinode.shEndpoints: CometBFT RPC 26657, gRPC 9090, REST 1317, EVM JSON-RPC 8545
(HTTP) / 8546 (WS). See chain/scripts/README.md
for how each genesis parameter maps to its specification section.
| Field | Value |
|---|---|
| Network name | GembaBlockchain (local devnet) |
| RPC URL | http://localhost:8545 |
| Chain ID | 821206 |
| Currency symbol | GMB |
This is a real public chain with honestly recorded risks. See CLAUDE.md §16 and
the full Architecture Decision Records in docs/risks.md. Public
launch is blocked until all of the following clear:
- MiCA classification confirmed in writing by a Bulgarian fintech lawyer (ADR-009).
- The upstream Cosmos EVM audit lands, plus our own review (ADR-006).
- The long-term security-budget tail reward is implemented and tested, and bonded-ratio monitoring is live (ADR-008).
Devnet, testnet, and closed formula-based institutional grants are not blocked by these gates.
This repository is public. Never commit .env, private keys, mnemonics, node keys,
keyrings, or database passwords. Copy .env.example to .env and
fill it in locally; .gitignore already excludes secrets and node data. The devnet
scripts use the well-known public cosmos/evm test mnemonics for reproducibility
only; these are published test vectors, not secrets, and must never be used on a
public network (see chain/scripts/README.md).
Source code is licensed under the Apache License 2.0; see LICENSE.
This matches the upstream cosmos/evm license. Documentation is licensed under
CC BY-SA 4.0.