Go "malformed module path: missing dot" - Fix in CI

By Daniel Zoghalchali·Latchkey

Go requires the first element of a module path to look like a host name, which means it must contain a dot. A bare name like "myapp" is rejected because it cannot be a real import host.

What this error means

A module command fails with malformed module path "myapp": missing dot in first path element. The module directive uses a bare name instead of a domain-style path.

go: malformed module path "myapp": missing dot in first path element

Diagnose it: module path, proxy, or checksum?

Go module errors name the module but rarely the layer that failed. Separate the three: the module path does not resolve, the proxy cannot serve it, or the checksum database disagrees with what was downloaded.

# what Go resolves and from where
go env GOPROXY GOSUMDB GOPRIVATE GOFLAGS

# does the module resolve at all, bypassing the build?
go list -m -versions github.com/org/module

# verify the module cache against go.sum
go mod verify

# private modules must be excluded from proxy and sumdb
go env -w GOPRIVATE=github.com/yourorg/*

Common causes

Bare module name in go.mod

The module directive names something without a dotted host, which Go cannot treat as an importable path.

go mod init with no domain

go mod init was run with a single word, producing an invalid module path.

How to fix it

Use a domain-style module path

1. Set the module directive to a host-prefixed path.

module github.com/acme/myapp

go 1.22

Re-init with a full path

1. Re-run go mod init with a domain-prefixed module path.

go mod init github.com/acme/myapp

How to prevent it

• Always use a host-prefixed module path even for private repos.
• Run go mod init with the full path from the start.
• Match the module path to the repo URL so imports resolve.

Frequently asked questions

Related guides

References

• Go documentation
• GitHub Actions documentation