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Kratos

Kratos is a lightweight Go framework for building cloud-native microservices. It provides small, explicit APIs for transport, middleware, registry, configuration, logging, encoding, and code generation so applications can focus on business logic.

Features

• API-first development with Protobuf and generated HTTP/gRPC code.
• Unified transport layer for HTTP and gRPC.
• Composable middleware for recovery, logging, validation, tracing, metrics, auth, and more.
• Pluggable registry, configuration, and encoding components.
• Standard-library log/slog based logging with OpenTelemetry extensions in contrib packages.
• Consistent metadata, errors, validation, OpenAPI, and code-generation workflows.
• A contrib ecosystem for optional integrations such as registries, config stores, middleware, encodings, and observability.

Installation

Requirements

• Go 1.25 or later
• protoc
• protoc-gen-go

Install the CLI

go install github.com/go-kratos/kratos/cmd/kratos/v3@latest
kratos upgrade

Create a Service

kratos new helloworld
cd helloworld
go mod tidy
kratos run

Visit http://localhost:8000/helloworld/kratos after the service starts.

For a fuller generated service flow:

kratos proto add api/helloworld/helloworld.proto
kratos proto client api/helloworld/helloworld.proto
kratos proto server api/helloworld/helloworld.proto -t internal/service
go generate ./...
kratos run

Usage Example

package main

import (
    "github.com/go-kratos/kratos/v3"
    "github.com/go-kratos/kratos/v3/transport/grpc"
    "github.com/go-kratos/kratos/v3/transport/http"
)

func main() {
    httpSrv := http.NewServer(http.Address(":8000"))
    grpcSrv := grpc.NewServer(grpc.Address(":9000"))

    app := kratos.New(
        kratos.Name("helloworld"),
        kratos.Version("v1.0.0"),
        kratos.Server(httpSrv, grpcSrv),
    )
    if err := app.Run(); err != nil {
        panic(err)
    }
}

v3 Migration

Kratos v3 reduces core dependencies and makes previously implicit behavior explicit. Review the v2 to v3 migration guide before upgrading production services.

Further Reading

• Documentation
• Examples
• Project Layout
• v2 to v3 Migration Guide
• Community Contribution Guide

Development

make test
make lint

Community

• Documentation
• WeChat Group
• Discord Group
• Discussions

Security

If you discover a security vulnerability in Kratos, please contact go-kratos@googlegroups.com. Security reports are handled privately before disclosure.

Contributors

Thank you for contributing to Kratos. The contribution guide is available in the Kratos documentation.

Acknowledgments

The following projects influenced Kratos design:

• go-kit/kit
• go-micro
• google/go-cloud
• go-zero
• beego

License

Kratos is open-sourced software licensed under the MIT license.