flow-go — Flow Network Reference Implementation in Go
Reference implementation of the Flow network in Go. Flow is a Layer 1 proof-of-stake blockchain built for consumer apps, AI Agents, and DeFi at scale. This repo hosts the node software — consensus, execution, verification, access, and collection roles — and the Cadence VM integration used on mainnet, testnet, and local networks.
TL;DR
- What: flow-go is the Go reference implementation of the Flow network, a Layer 1 proof-of-stake blockchain.
- Who it’s for: protocol contributors, node operators, and teams building infrastructure on or adjacent to Flow.
- Why use it: canonical source of truth for Flow consensus (HotStuff), multi-role architecture, Cadence VM integration, and Flow EVM.
- Status: see Releases for the latest version. Live on mainnet.
- License: AGPL-3.0
- Related repos: cadence (language) · flow-cli (CLI) · fcl-js (JS client) · flow-go-sdk (Go client)
- The reference Go implementation for the Flow network, open-sourced since 2019.
Table of Contents
Getting started
Documentation
You can find an overview of the Flow architecture on the documentation website.
Development on Flow is divided into work streams. Each work stream has a home directory containing high-level
documentation for the stream, as well as links to documentation for relevant components used by that work stream.
The following table lists all work streams and links to their home directory and documentation:
Installation
-
Clone this repository
-
Install Go (Flow requires Go 1.26 and later)
-
Install Docker, which is used for running a local network and integration tests
-
Make sure the GOPATH and GOBIN environment variables
are set, and GOBIN is added to your path:
export GOPATH=$(go env GOPATH)
export GOBIN=$GOPATH/bin
export PATH=$PATH:$GOBIN
Add these to your shell profile to persist them for future runs.
-
Then, run the following command:
make install-tools
At this point, you should be ready to build, test, and run Flow! 🎉
Development Workflow
Testing
Flow has a unit test suite and an integration test suite. Unit tests for a module live within the module they are
testing. Integration tests live in integration/tests.
Run the unit test suite:
make test
Run the integration test suite:
make integration-test
Building
The recommended way to build and run Flow for local development is using Docker.
Build a Docker image for all nodes:
make docker-native-build-flow
Build a Docker image for a particular node role (replace $ROLE with collection, consensus, etc.):
make docker-native-build-$ROLE
Building a binary for the access node
Build the binary for an access node that can be run directly on the machine without using Docker.
make docker-native-build-access-binary
this builds a binary for Linux/x86_64 machine.
The make command will generate a binary called flow_access_node
Importing the module
When importing the github.com/onflow/flow-go module in your Go project, testing or building your project may require setting extra Go flags because the module requires cgo. In particular, CGO_ENABLED must be set to 1 if cgo isn’t enabled by default. This constraint comes from the underlying cryptography library. Refer to the crypto repository build for more details.
Local Network
A local version of the network can be run for manual testing and integration. See
the Local Network Guide for instructions.
Code Generation
Generated code is kept up to date in the repository, so should be committed whenever it changes.
Run all code generators:
make generate
Generate protobuf stubs:
make generate-proto
Generate OpenAPI schema models:
make generate-openapi
Generate mocks used for unit tests:
make generate-mocks
Mocks
We use github.com/vektra/mockery for mocking interfaces within tests. The configuration is in .mockery.yaml.
Adding and updating packages
You can add new packages by their fully qualified name. e.g.
github.com/onflow/flow-go/module/execution:
This will add all interfaces within the module/execution/ (non-recursive).
Mocking functions
Mockery dropped support for generating function mocks. Instead, you can use this pattern:
- Create a
mock_interfaces directory in the package where the function mock exists.
- Add a file that mocks the function. for example, this mocks the `StateMachineEventsTelemetryFactory(candidateView uint64) protocol_state.StateMachineTelemetryConsumer
package mockinterfaces
import "github.com/onflow/flow-go/state/protocol/protocol_state"
// ExecForkActor allows to create a mock for the ExecForkActor callback
type StateMachineEventsTelemetryFactory interface {
Execute(candidateView uint64) protocol_state.StateMachineTelemetryConsumer
}
- Add the package to
.mockery.yaml. Note: specify the directory where you want the mock to be placed.
github.com/onflow/flow-go/state/protocol/protocol_state/mock_interfaces:
config:
dir: "state/protocol/protocol_state/mock"
FAQ
What is flow-go?
flow-go is the Go reference implementation of the Flow network — a Layer 1 proof-of-stake blockchain. It implements the node software (Access, Collection, Consensus, Execution, Verification roles), the HotStuff consensus algorithm, ledger, storage, networking, and cryptography subsystems.
How does flow-go differ from the Cadence repo?
flow-go is the protocol / node implementation. onflow/cadence is the Cadence smart contract language (compiler, interpreter, type system). flow-go embeds the Cadence VM to execute transactions, but the language itself is developed in the Cadence repo.
What are the five node roles in Flow?
Access, Collection, Consensus, Execution, and Verification. Each has its own entry point under /cmd/. There is also an Observer service for staking-free read-only access.
Which Go version does flow-go require?
Go 1.26 or later. See the Installation section for the full environment setup.
Where is the consensus algorithm implemented?
Under /consensus/hotstuff. HotStuff is the BFT consensus family used by Flow.
How do I run a local Flow network?
See the Local Network Guide for a full local multi-role network suitable for integration testing.
Where do I report a security issue?
See SECURITY.md for the responsible disclosure policy.
About Flow
This repo is the Go reference implementation of the Flow network, a Layer 1 blockchain built for consumer applications, AI Agents, and DeFi at scale.
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