diff --git a/DESCRIPTION b/DESCRIPTION
index 35efac7..5655eb6 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: r.releases.utils
 Title: Utilities for An R Universe of Package Releases
 Description: Utilities for an R universe of package releases.
-Version: 0.0.5
+Version: 0.0.6
 License: MIT + file LICENSE
 URL:
   https://r-releases.github.io/r.releases.utils/,
diff --git a/NAMESPACE b/NAMESPACE
index 6bd490d..24a3379 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -9,6 +9,8 @@ export(try_message)
 importFrom(gh,gh)
 importFrom(jsonlite,parse_json)
 importFrom(jsonlite,read_json)
+importFrom(nanonext,ncurl)
 importFrom(nanonext,parse_url)
+importFrom(nanonext,status_code)
 importFrom(pkgsearch,cran_package)
 importFrom(vctrs,vec_rbind)
diff --git a/NEWS.md b/NEWS.md
index f3f949c..8447807 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,7 @@
+# r.releases.utils 0.0.6
+
+* Check URL exists as part of package verification.
+
 # r.releases.utils 0.0.5
 
 * Write pretty JSON to `packages.json` (@llrs, https://github.com/r-releases/help/issues/4).
diff --git a/R/assert_package.R b/R/assert_package.R
index 228f668..d8b08c7 100644
--- a/R/assert_package.R
+++ b/R/assert_package.R
@@ -47,6 +47,17 @@ assert_package <- function(name, url) {
   if (identical(owner, "cran")) {
     return(paste("URL", shQuote(url), "appears to use a CRAN mirror."))
   }
+  status <- nanonext::ncurl(url)[["status"]]
+  if (status != 200L) {
+    return(
+      paste(
+        "URL",
+        shQuote(url),
+        "returned HTTP error",
+        nanonext::status_code(status)
+      )
+    )
+  }
   assert_cran_url(name = name, url = url)
 }
 
diff --git a/R/package.R b/R/package.R
index 704c66f..f73f627 100644
--- a/R/package.R
+++ b/R/package.R
@@ -4,7 +4,7 @@
 #' @family help
 #' @importFrom gh gh
 #' @importFrom jsonlite parse_json read_json
-#' @importFrom nanonext parse_url
+#' @importFrom nanonext ncurl parse_url status_code
 #' @importFrom pkgsearch cran_package
 #' @importFrom vctrs vec_rbind
 NULL
diff --git a/tests/test-assert_package.R b/tests/test-assert_package.R
index 8eafc58..5bef07d 100644
--- a/tests/test-assert_package.R
+++ b/tests/test-assert_package.R
@@ -140,6 +140,17 @@ stopifnot(
   )
 )
 
+stopifnot(
+  grepl(
+    "returned HTTP error",
+    r.releases.utils::assert_package(
+      name = "afantasticallylongandimpossiblepackage",
+      url = "https://github.com/r-lib/afantasticallylongandimpossiblepackage"
+    ),
+    fixed = TRUE
+  )
+)
+
 stopifnot(
   is.null(
     r.releases.utils::assert_package(