renv uses a lockfile to capture the state of your library at some point in time. It is stored as a collection of records, with different records defining:

  • The version of renv used when generating the lockfile;
  • The version of R used in that project;
  • The R repositories that were active when the lockfile was created;
  • Package records defining each R package, their version, and their installation source.

Here is an example lockfile, including the packages markdown and mime:

{
  "renv": {
    "Version": "1.0.0"
  },
  "R": {
    "Version": "3.6.1",
    "Repositories": [
      {
        "Name": "CRAN",
        "URL": "https://cloud.r-project.org"
      }
    ]
  },
  "Packages": {
    "markdown": {
      "Package": "markdown",
      "Version": "1.0",
      "Source": "CRAN",
      "Hash": "4584a57f565dd7987d59dda3a02cfb41"
    },
    "mime": {
      "Package": "mime",
      "Version": "0.7",
      "Source": "CRAN",
      "Hash": "908d95ccbfd1dd274073ef07a7c93934"
    }
  }
}

The function renv::snapshot() is used to create this lockfile, and by default writes these records to the file renv.lock. Later, if you need to reinstall the specific package versions as recorded in renv.lock, you can use renv::restore().