diff --git a/archivebot-compress-db b/archivebot-compress-db
new file mode 100755
index 0000000..d4b96c1
--- /dev/null
+++ b/archivebot-compress-db
@@ -0,0 +1,32 @@
+#!/bin/bash
+# Compresses the database in the current directory using the filename of the .json file for naming.
+if [[ ! -f wpull.db ]]; then
+	printf 'Error: wpull.db does not exist.\n' >&2
+	exit 1
+fi
+
+if lsof wpull.db >/dev/null; then
+	printf 'Error: wpull.db is opened by another process.\n' >&2
+	exit 1
+fi
+
+jsonfiles=(*.json)
+if [[ ${#jsonfiles[@]} -eq 0 ]]; then
+	printf 'Error: no .json file\n' >&2
+	exit 1
+elif [[ ${#jsonfiles[@]} -gt 1 ]]; then
+	printf 'Error: two or more .json files\n' >&2
+	exit 1
+fi
+
+outname="${jsonfiles[0]%.json}-wpull.db.zst"
+if [[ -e "${outname}" ]]; then
+	printf 'Error: %q already exists\n' "${outname}" >&2
+	exit 1
+fi
+
+printf 'WAL checkpoint...\n'
+sqlite3 wpull.db 'PRAGMA wal_checkpoint'
+
+printf 'Compressing...\n'
+zstd -10 -o "${outname}" wpull.db