diff --git a/backend/src/langs.ts b/backend/src/langs.ts
index 1ece6fe..3c2999a 100644
--- a/backend/src/langs.ts
+++ b/backend/src/langs.ts
@@ -1020,6 +1020,15 @@ main:
 	.data
 message:
 	.string "Hello, world!\\n"
+`,
+  },
+  mongodb: {
+    aliases: ["mongo", "mongod"],
+    name: "MongoDB",
+    repl: `while ps -u "$(id -un)" -o comm | grep -q mongod; do sleep 0.01; done && rm -rf data && mkdir data && (mongod --dbpath=data --unixSocketPrefix="$PWD" --bind_ip=, &) && until mongo --host "$PWD/mongodb-27017.sock" --eval ' ' &>/dev/null; do sleep 0.01; done && mongo --host "$PWD/mongodb-27017.sock"`,
+    main: "main.js",
+    run: `while ps -u "$(id -un)" -o comm | grep -q mongod; do sleep 0.01; done && rm -rf data && mkdir data && (mongod --dbpath=data --unixSocketPrefix="$PWD" --bind_ip=, &) && until mongo --host "$PWD/mongodb-27017.sock" --eval ' ' &>/dev/null; do sleep 0.01; done && mongo --host "$PWD/mongodb-27017.sock" --shell main.js`,
+    template: `print("Hello, world!")
 `,
   },
   mumps: {
diff --git a/scripts/docker-install-phase3c.bash b/scripts/docker-install-phase3c.bash
index aeb3677..0633966 100755
--- a/scripts/docker-install-phase3c.bash
+++ b/scripts/docker-install-phase3c.bash
@@ -13,6 +13,9 @@ libtinfo5
 gcc-mips64-linux-gnuabi64
 qemu-user-static
 
+# MongoDB
+mongodb
+
 # MUMPS
 fis-gtm