diff --git a/pyproject.toml b/pyproject.toml
index b29d003..9908926 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,3 +1,7 @@
+[tool.black]
+line-length = 100
+target-version = ["py36"]
+
 [tool.isort]
 src_paths = ["tools", "zulip", "zulip_bots", "zulip_botserver"]
 profile = "black"
diff --git a/requirements.txt b/requirements.txt
index 055dca1..2a06771 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,7 @@
 crayons
 twine
 coverage>=4.4.1
+black
 isort
 flake8
 mock