actions/upload-artifact

Upload files from a job so other jobs or a person can download them after the run.

Official actionCategory: ArtifactsLatest v4View on GitHub

What it does

actions/upload-artifact persists files produced by a job so a later job can download them or a human can grab them from the run summary.

v4 rewrote the backend for speed and immutability, and it is not cross-compatible with v3: both ends of an upload/download pair must be on v4.

workflow (.yml)

steps:
  - uses: actions/upload-artifact@v4
    with:
      name: test-results
      path: reports/
      retention-days: 7

Input	Description	Default	Required
`name`	Artifact name.	`artifact`	No
`path`	File, directory, or glob to upload.	-	Yes
`if-no-files-found`	Behavior when nothing matches: warn, error, or ignore.	`warn`	No
`retention-days`	Days to keep the artifact (up to the repo maximum).	`repo default`	No
`overwrite`	Replace an existing artifact of the same name.	`false`	No

Output	Description
`artifact-id`	Numeric id of the uploaded artifact.
`artifact-url`	URL of the artifact in the run.

In v4 an artifact name is immutable within a run. Uploading the same name twice fails unless overwrite: true.

To collect artifacts from a matrix, give each leg a unique name (for example include the matrix value) and merge on download.

Conflict: an artifact with this name already exists on the workflow run (v4) means a duplicate name. Use unique names or overwrite: true.
Mixing upload-artifact@v4 with download-artifact@v3 (or vice versa) fails. Keep both on v4.

Artifacts are downloadable by anyone with read access to the repo. Never upload secrets, tokens, or .env files.

What changed in upload-artifact v4?

Faster uploads, immutable artifacts, and per-run name uniqueness. It is not compatible with v3, so upload and download must both be v4.

How long are artifacts kept?

Up to the repository or organization retention limit (90 days by default), overridable per upload with retention-days.