diff --git a/.windsurf/rules/next.md b/.windsurf/rules/next.md
new file mode 100644
index 00000000..fa377ded
--- /dev/null
+++ b/.windsurf/rules/next.md
@@ -0,0 +1,42 @@
+---
+trigger: manual
+description:
+globs: 
+---
+
+### Translations
+
+```typescript
+import {useT} from "web/lib/locale";
+
+const t = useT()
+t("common.key", "English translations")
+```
+
+Translations should go to the JSON files in `web/messages` (`de.json` and `fr.json`, as of now).
+
+### Misc coding tips
+
+We have many useful hooks that should be reused rather than rewriting them again.
+
+---
+
+We prefer using lodash functions instead of reimplementing them with for loops:
+
+```ts
+import {keyBy, uniq} from 'lodash'
+
+const betsByUserId = keyBy(bets, 'userId')
+const betIds = uniq(bets, (b) => b.id)
+```
+
+---
+
+Instead of Sets, consider using lodash's uniq function:
+
+```ts
+const betIds = uniq([])
+for (const id of betIds) {
+...
+}
+```
diff --git a/docs/knowledge.md b/docs/knowledge.md
index 8c85d45f..25883a70 100644
--- a/docs/knowledge.md
+++ b/docs/knowledge.md
@@ -424,6 +424,17 @@ const res = await pg.manyOrNone(query)
 
 Use these functions instead of string concatenation.
 
+### Translations
+
+```typescript
+import {useT} from "web/lib/locale";
+
+const t = useT()
+t("common.key", "English translations")
+```
+
+Translations should go to the JSON files in `web/messages` (`de.json` and `fr.json`, as of now).
+
 ### Misc coding tips
 
 We have many useful hooks that should be reused rather than rewriting them again.