---
description: >
  Add the `post-processors` block to a `build` block to define a list of post-processors to apply to an artifact. Learn how to configure nested `post-processors` blocks.
page_title: post-processors block reference
---

# `post-processors` block

This topic provides reference information about the `post-processors` block.

## Description

Add a `post-processors` block to your `build` block to include a list of [post-processor](/packer/docs/templates/hcl_templates/blocks/build/post-processor) configurations. Packer runs the post-processors for an artifact after each build. 

```hcl
# builds.pkr.hcl
build {
  # ...
  post-processors {
    post-processor "shell-local" { # create an artifice.txt file containing "hello"
      inline = [ "echo hello > artifice.txt" ]
    }
    post-processor "artifice" { # tell packer this is now the new artifact
      files = ["artifice.txt"]
    }
    post-processor "checksum" { # checksum artifice.txt
      checksum_types = [ "md5", "sha512" ] # checksum the artifact
      keep_input_artifact = true           # keep the artifact
    }
  }

}
```

The [`post-processor` block](/packer/docs/templates/hcl_templates/blocks/build/post-processor)
allows to define multiple post-processors that will run from the `Artifact` of
each build. Read the `post-processor` documentation to know how to use a
post-processor.

### Difference between a `post-processor` and a `post-processors` block

These two templates are doing the same thing:

```hcl
# builds.pkr.hcl
build {
  # ... build image
  post-processor "checksum" { # checksum image
    checksum_types = [ "md5", "sha512" ] # checksum the artifact
  }

  post-processor "amazon-import" { # upload image to AWS
  }

  post-processor "googlecompute-import" { # upload image to GCP
  }
}
```

```hcl
# builds.pkr.hcl
build {
  # ... build image
  post-processors {
    post-processor "checksum" { # checksum image
      checksum_types = [ "md5", "sha512" ] # checksum the artifact
    }
  }

  post-processors {
    post-processor "amazon-import" { # upload image to AWS
    }
  }

  post-processors {
    post-processor "googlecompute-import" { # upload image to GCP
    }
  }
}
```

Each of these `post-processors` will start after each build -- that is, after
each provision step has run on each source --. In all cases the source image is
going to be deleted.
