diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d113aab..cd4b22c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -16,15 +16,17 @@ jobs:
       - name: Install project
         run: |
           pip install -U "pip>=21.3.1"
-          pip install -e .[test] -c requirements.txt -c requirements-test.txt
+          pip install -e .[test,mypy] -c requirements.txt -c requirements-test.txt -c requirements-mypy.txt
       - name: Run tests
-        run: |
-          pytest -v --cov --cov-report=xml ./tests
+        run: pytest -v --cov --cov-report=xml ./tests
+      - name: Run mypy
+        run: mypy ./src/runboat ./tests
       - uses: codecov/codecov-action@v1
   build-image:
     runs-on: ubuntu-latest
     needs:
       - test
+    if: ${{ github.repository_owner == 'sbidoul' && github.ref == 'refs/heads/main' }}
     steps:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v1
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index fb8818b..fc5094c 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -39,4 +39,4 @@ repos:
     rev: v2.29.0
     hooks:
       - id: pyupgrade
-        args: ["--py38-plus"]
+        args: ["--py39-plus"]
diff --git a/pyproject.toml b/pyproject.toml
index c1509c7..ca069ad 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -27,6 +27,9 @@ test = [
     "pytest-cov",
     "pytest-dotenv",
 ]
+mypy = [
+    "mypy",
+]
 
 [project.urls]
 Home = "https://github.com/sbidoul/runboat"
@@ -39,3 +42,23 @@ env_override_existing_values = 1
 env_files = [".env.test"]
 
 # flake8 config is in .flake8
+
+[tool.mypy]
+strict = true
+show_error_codes = true
+
+[[tool.mypy.overrides]]
+module = "uvicorn.*"
+ignore_missing_imports = true
+
+[[tool.mypy.overrides]]
+module = "urllib3.*"
+ignore_missing_imports = true
+
+[[tool.mypy.overrides]]
+module = "kubernetes.*"
+ignore_missing_imports = true
+
+[[tool.mypy.overrides]]
+module = "ansi2html"
+ignore_missing_imports = true
diff --git a/requirements-mypy.txt b/requirements-mypy.txt
new file mode 100644
index 0000000..444c145
--- /dev/null
+++ b/requirements-mypy.txt
@@ -0,0 +1,4 @@
+# frozen requirements generated by pip-deepfreeze
+mypy==0.910
+mypy-extensions==0.4.3
+toml==0.10.2
diff --git a/src/runboat/api.py b/src/runboat/api.py
index 11dbe83..ca81e4c 100644
--- a/src/runboat/api.py
+++ b/src/runboat/api.py
@@ -1,14 +1,14 @@
 import datetime
 from typing import Optional
 
-from ansi2html import Ansi2HTMLConverter  # type: ignore
+from ansi2html import Ansi2HTMLConverter
 from fastapi import APIRouter, Depends, HTTPException, status
 from fastapi.responses import HTMLResponse
 from pydantic import BaseModel
 from starlette.status import HTTP_404_NOT_FOUND
 
 from . import github, models
-from .controller import controller
+from .controller import Controller, controller
 from .deps import authenticated
 from .settings import settings
 
@@ -60,12 +60,12 @@ class Build(BaseModel):
 
 
 @router.get("/status", response_model=Status)
-async def controller_status():
+async def controller_status() -> Controller:
     return controller
 
 
 @router.get("/repos", response_model=list[Repo])
-async def repos():
+async def repos() -> list[models.Repo]:
     return [models.Repo(name=name) for name in settings.supported_repos]
 
 
@@ -74,7 +74,7 @@ async def repos():
     response_model=list[Build],
     response_model_exclude_none=True,
 )
-async def builds(repo: Optional[str] = None):
+async def builds(repo: Optional[str] = None) -> list[models.Build]:
     return controller.db.search(repo)
 
 
@@ -82,7 +82,7 @@ async def builds(repo: Optional[str] = None):
     "/builds/trigger/branch",
     dependencies=[Depends(authenticated)],
 )
-async def trigger_branch(repo: str, branch: str):
+async def trigger_branch(repo: str, branch: str) -> None:
     """Trigger build for a branch."""
     branch_info = await github.get_branch_info(repo, branch)
     await controller.deploy_or_start(
@@ -97,7 +97,7 @@ async def trigger_branch(repo: str, branch: str):
     "/builds/trigger/pr",
     dependencies=[Depends(authenticated)],
 )
-async def trigger_pull(repo: str, pr: int):
+async def trigger_pull(repo: str, pr: int) -> None:
     """Trigger build for a pull request."""
     pull_info = await github.get_pull_info(repo, pr)
     await controller.deploy_or_start(
@@ -116,7 +116,7 @@ async def _build_by_name(name: str) -> models.Build:
 
 
 @router.get("/builds/{name}", response_model=Build)
-async def build(name: str):
+async def build(name: str) -> models.Build:
     return await _build_by_name(name)
 
 
@@ -124,42 +124,42 @@ async def build(name: str):
     "/builds/{name}/init-log",
     response_class=HTMLResponse,
 )
-async def init_log(name: str):
+async def init_log(name: str) -> str:
     build = await _build_by_name(name)
     log = await build.init_log()
     if not log:
         raise HTTPException(status_code=HTTP_404_NOT_FOUND, detail="No log found.")
-    return Ansi2HTMLConverter().convert(log)
+    return Ansi2HTMLConverter().convert(log)  # type: ignore [no-any-return]
 
 
 @router.get(
     "/builds/{name}/log",
     response_class=HTMLResponse,
 )
-async def log(name: str):
+async def log(name: str) -> str:
     build = await _build_by_name(name)
     log = await build.log()
     if not log:
         raise HTTPException(status_code=HTTP_404_NOT_FOUND, detail="No log found.")
-    return Ansi2HTMLConverter().convert(log)
+    return Ansi2HTMLConverter().convert(log)  # type: ignore [no-any-return]
 
 
 @router.post("/builds/{name}/start")
-async def start(name: str):
+async def start(name: str) -> None:
     """Start the deployment."""
     build = await _build_by_name(name)
     await build.start()
 
 
 @router.post("/builds/{name}/stop")
-async def stop(name: str):
+async def stop(name: str) -> None:
     """Stop the deployment."""
     build = await _build_by_name(name)
     await build.stop()
 
 
 @router.delete("/builds/{name}", dependencies=[Depends(authenticated)])
-async def delete(name: str):
+async def delete(name: str) -> None:
     """Delete the deployment and drop the database."""
     build = await _build_by_name(name)
     await build.undeploy()
diff --git a/src/runboat/controller.py b/src/runboat/controller.py
index 7180bd0..cc3b8a5 100644
--- a/src/runboat/controller.py
+++ b/src/runboat/controller.py
@@ -30,7 +30,7 @@ class Controller:
     """
 
     db: BuildsDb
-    _tasks: list[asyncio.Task]
+    _tasks: list[asyncio.Task[None]]
     _wakeup_initializer: asyncio.Event
     _wakeup_stopper: asyncio.Event
     _wakeup_undeployer: asyncio.Event
diff --git a/src/runboat/k8s.py b/src/runboat/k8s.py
index b0b920b..35f2f13 100644
--- a/src/runboat/k8s.py
+++ b/src/runboat/k8s.py
@@ -11,12 +11,12 @@ from importlib import resources
 from pathlib import Path
 from typing import Any, Callable, Generator, Optional, TypedDict, cast
 
-import urllib3  # type: ignore
+import urllib3
 from jinja2 import Template
-from kubernetes import client, config, watch  # type: ignore
-from kubernetes.client.exceptions import ApiException  # type: ignore
-from kubernetes.client.models.v1_deployment import V1Deployment  # type: ignore
-from kubernetes.client.models.v1_job import V1Job  # type: ignore
+from kubernetes import client, config, watch
+from kubernetes.client.exceptions import ApiException
+from kubernetes.client.models.v1_deployment import V1Deployment
+from kubernetes.client.models.v1_job import V1Job
 from pydantic import BaseModel
 
 from .settings import settings
diff --git a/src/runboat/models.py b/src/runboat/models.py
index 609e506..7a2c483 100644
--- a/src/runboat/models.py
+++ b/src/runboat/models.py
@@ -4,7 +4,7 @@ import uuid
 from enum import Enum
 from typing import Optional
 
-from kubernetes.client.models.v1_deployment import V1Deployment  # type: ignore
+from kubernetes.client.models.v1_deployment import V1Deployment
 from pydantic import BaseModel
 
 from . import github, k8s
diff --git a/src/runboat/uvicorn.py b/src/runboat/uvicorn.py
index c60e707..aa60081 100644
--- a/src/runboat/uvicorn.py
+++ b/src/runboat/uvicorn.py
@@ -1,4 +1,4 @@
-from uvicorn.workers import UvicornWorker  # type: ignore
+from uvicorn.workers import UvicornWorker
 
 from .settings import settings
 
diff --git a/src/runboat/webui.py b/src/runboat/webui.py
index 7910ac7..9f4a99f 100644
--- a/src/runboat/webui.py
+++ b/src/runboat/webui.py
@@ -1,7 +1,7 @@
 from pathlib import Path
 from typing import Optional
 
-from fastapi import APIRouter, HTTPException, Request, status
+from fastapi import APIRouter, HTTPException, Request, Response, status
 from fastapi.responses import HTMLResponse, RedirectResponse
 from fastapi.templating import Jinja2Templates
 
@@ -13,12 +13,12 @@ templates = Jinja2Templates(directory=str(Path(__file__).parent / "webui"))
 
 
 @router.get("/builds/{name}", response_class=HTMLResponse)
-async def build(request: Request, name: str, live: Optional[str] = None):
+async def build(request: Request, name: str, live: Optional[str] = None) -> Response:
     build = controller.db.get(name)
     if not build:
         raise HTTPException(status.HTTP_404_NOT_FOUND)
     if live is not None and build.status == BuildStatus.started:
         return RedirectResponse(url=build.deploy_link)
     return templates.TemplateResponse(
-        "build.html", {"request": request, "build": build}
+        "build.html.jinja", {"request": request, "build": build}
     )
diff --git a/src/runboat/webui/build.html b/src/runboat/webui/build.html.jinja
similarity index 83%
rename from src/runboat/webui/build.html
rename to src/runboat/webui/build.html.jinja
index 6f63d09..39c53ba 100644
--- a/src/runboat/webui/build.html
+++ b/src/runboat/webui/build.html.jinja
@@ -18,15 +18,18 @@
         <p>Branch: <a href="{{ build.repo_link }}">{{ build.target_branch }}</a></p>
         {% endif %}
         <p>Commit: <a href="{{ build.repo_commit_link }}">{{ build.git_commit }}</a></p>
-        <p>Status: {{ build.status }}</p>
+        <p>Status: {{ build.status.value }}</p>
         <p>
             Logs:
-            <a href="/api/v1/builds/{{ build.name }}/init-log" target="_blank">build log</a>
+            <a href="/api/v1/builds/{{ build.name }}/init-log" target="_blank">init log</a>
+            {% if build.status == 'started' %}
             |
-            <a href="/api/v1/builds/{{ build.name }}/log" target="_blank">run log</a>
+            <a href="/api/v1/builds/{{ build.name }}/log" target="_blank">log</a>
+            |
+            <a href="{{ build.deploy_link }}">=> live</a>
+            {% endif %}
         </p>
         {% if build.status == 'started' %}
-        <p><a href="{{ build.deploy_link }}">=> live</a></p>
         <button onclick="stop()">stop</button>
         {% else %}
         <button onclick="start()">start</button>
diff --git a/tests/test_build_images.py b/tests/test_build_images.py
index debf669..d45086b 100644
--- a/tests/test_build_images.py
+++ b/tests/test_build_images.py
@@ -4,20 +4,20 @@ from runboat.build_images import get_build_image, get_main_branch, is_branch_sup
 from runboat.exceptions import BranchNotSupported
 
 
-def test_get_main_branch():
+def test_get_main_branch() -> None:
     assert get_main_branch("15.0") == "15.0"
     assert get_main_branch("15.0-ocabot-merge") == "15.0"
     with pytest.raises(BranchNotSupported):
         get_main_branch("8.0")
 
 
-def test_is_branch_supported():
+def test_is_branch_supported() -> None:
     assert is_branch_supported("15.0")
     assert is_branch_supported("15.0-ocabot-merge")
     assert not is_branch_supported("8.0")
 
 
-def test_get_build_image():
+def test_get_build_image() -> None:
     assert get_build_image("15.0") == "ghcr.io/oca/oca-ci/py3.8-odoo15.0:latest"
     assert get_build_image("15.0-zzz") == "ghcr.io/oca/oca-ci/py3.8-odoo15.0:latest"
     with pytest.raises(BranchNotSupported):
diff --git a/tests/test_db.py b/tests/test_db.py
index 941e82f..4d3cba7 100644
--- a/tests/test_db.py
+++ b/tests/test_db.py
@@ -29,14 +29,14 @@ def _make_build(
     )
 
 
-def test_add():
+def test_add() -> None:
     db = BuildsDb()
     assert db.add(_make_build())  # new
     assert not db.add(_make_build())  # no change
     assert db.add(_make_build(status=BuildStatus.failed))
 
 
-def test_remove():
+def test_remove() -> None:
     db = BuildsDb()
     assert not db.remove("not-a-build")
     build = _make_build()
@@ -44,7 +44,7 @@ def test_remove():
     assert db.remove(build.name)
 
 
-def test_get_for_commit():
+def test_get_for_commit() -> None:
     db = BuildsDb()
     build = _make_build()
     db.add(build)
@@ -62,7 +62,7 @@ def test_get_for_commit():
     )
 
 
-def test_search():
+def test_search() -> None:
     db = BuildsDb()
     db.add(build1 := _make_build(name="b1", repo="oca/repo1"))
     db.add(_make_build(name="b2", repo="oca/repo2"))
@@ -70,7 +70,7 @@ def test_search():
     assert db.search("oca/repo1") == [build1]
 
 
-def test_count_by_status():
+def test_count_by_status() -> None:
     db = BuildsDb()
     db.add(_make_build(name="b1", status=BuildStatus.started))
     db.add(_make_build(name="b2", status=BuildStatus.stopped))
@@ -79,7 +79,7 @@ def test_count_by_status():
     assert db.count_by_status(BuildStatus.failed) == 0
 
 
-def test_count_by_init_status():
+def test_count_by_init_status() -> None:
     db = BuildsDb()
     db.add(_make_build(name="b1", init_status=BuildInitStatus.started))
     db.add(_make_build(name="b2", init_status=BuildInitStatus.todo))
@@ -88,7 +88,7 @@ def test_count_by_init_status():
     assert db.count_by_init_status(BuildInitStatus.failed) == 0
 
 
-def test_count_all():
+def test_count_all() -> None:
     db = BuildsDb()
     assert db.count_all() == 0
     db.add(_make_build(name="b1"))
diff --git a/tests/test_k8s.py b/tests/test_k8s.py
index 68be498..74af7d3 100644
--- a/tests/test_k8s.py
+++ b/tests/test_k8s.py
@@ -10,5 +10,5 @@ from runboat.k8s import _split_image_name_tag
         ("postgres:12", ("postgres", "12")),
     ],
 )
-def test_split_image_name_tag(image, expected):
+def test_split_image_name_tag(image: str, expected: tuple[str, str]) -> None:
     assert _split_image_name_tag(image) == expected
diff --git a/tests/test_render_kubefiles.py b/tests/test_render_kubefiles.py
index a150afb..e703e8c 100644
--- a/tests/test_render_kubefiles.py
+++ b/tests/test_render_kubefiles.py
@@ -65,7 +65,7 @@ patches:
 """
 
 
-def test_render_kubefiles():
+def test_render_kubefiles() -> None:
     deployment_vars = make_deployment_vars(
         mode=DeploymentMode.deployment,
         build_name="build-name",