diff --git a/.github/workflows/checks.yaml b/.github/workflows/checks.yaml
index 113c7e6..4365257 100644
--- a/.github/workflows/checks.yaml
+++ b/.github/workflows/checks.yaml
@@ -25,6 +25,8 @@ jobs:
         run: flake8 pro_tes/ setup.py
       - name: Lint with Pylint
         run: pylint pro_tes/ setup.py
+      - name: Type check with mypy
+        run: mypy pro_tes/
   test:
     name: Run tests
     runs-on: ubuntu-latest
diff --git a/pro_tes/ga4gh/tes/models.py b/pro_tes/ga4gh/tes/models.py
index 4d8d3b6..2f0b039 100644
--- a/pro_tes/ga4gh/tes/models.py
+++ b/pro_tes/ga4gh/tes/models.py
@@ -38,7 +38,7 @@ class TesCreateTaskResponse(CustomBaseModel):
 
 class TesExecutor(CustomBaseModel):
     image: str = Field(
-        [""],
+        default=[""],
         description=(
             "Name of the container image. The string will be passed as        "
             "    the image\nargument to the containerization run command.     "
@@ -46,29 +46,29 @@ class TesExecutor(CustomBaseModel):
             "              - `gcr.io/my-org/my-image`\n   -                "
             " `myregistryhost:5000/fedora/httpd:version1.0`"
         ),
-        example="ubuntu:20.04",
+        examples=["ubuntu:20.04"],
     )
     command: list[str] = Field(
-        [""],
+        default=[""],
         description=(
             "A sequence of program arguments to execute, where the            "
             " first argument\nis the program to execute (i.e. argv).          "
             '  Example:\n```\n{\n  "command" :                 ["/bin/md5",'
             ' "/data/file1"]\n}\n```'
         ),
-        example=["/bin/md5", "/data/file1"],
+        examples=["/bin/md5", "/data/file1"],
     )
     workdir: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             "The working directory that the command will be executed          "
             "   in.\nIf not defined, the system will default to the directory"
             " set                by\nthe container image."
         ),
-        example="/data/",
+        examples=["/data/"],
     )
     stdin: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             "Path inside the container to a file which will be            "
             " piped\nto the executor's stdin. This must be an absolute path. "
@@ -79,53 +79,53 @@ class TesExecutor(CustomBaseModel):
             ' STDIN\n```\n{\n  "command" : ["/bin/md5"],\n  "stdin"           '
             '      : "/data/file1"\n}\n```'
         ),
-        example="/data/file1",
+        examples=["/data/file1"],
     )
     stdout: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             "Path inside the container to a file where the            "
             " executor's\nstdout will be written to. Must be an absolute"
             ' path.                Example:\n```\n{\n  "stdout" :'
             ' "/tmp/stdout.log"\n}\n```'
         ),
-        example="/tmp/stdout.log",
+        examples=["/tmp/stdout.log"],
     )
     stderr: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             "Path inside the container to a file where the            "
             " executor's\nstderr will be written to. Must be an absolute"
             ' path.                 Example:\n```\n{\n  "stderr" :'
             ' "/tmp/stderr.log"\n}\n```'
         ),
-        example="/tmp/stderr.log",
+        examples=["/tmp/stderr.log"],
     )
     env: Optional[dict[str, str]] = Field(
-        None,
+        default=None,
         description=(
             "Enviromental variables to set within the container.            "
             ' Example:\n```\n{\n  "env" : {\n                "ENV_CONFIG_PATH"'
             ' : "/data/config.file",\n    "BLASTDB" :            '
             ' "/data/GRC38",\n    "HMMERDB" : "/data/hmmer"\n  }\n}\n```'
         ),
-        example={"BLASTDB": "/data/GRC38", "HMMERDB": "/data/hmmer"},
+        examples=[{"BLASTDB": "/data/GRC38", "HMMERDB": "/data/hmmer"}],
     )
 
 
 class TesExecutorLog(CustomBaseModel):
     start_time: Optional[str] = Field(
-        None,
+        default=None,
         description="Time the executor started, in RFC 3339 format.",
-        example="2020-10-02T10:00:00-05:00",
+        examples=["2020-10-02T10:00:00-05:00"],
     )
     end_time: Optional[str] = Field(
-        None,
+        default=None,
         description="Time the executor ended, in RFC 3339 format.",
-        example="2020-10-02T11:00:00-05:00",
+        examples=["2020-10-02T11:00:00-05:00"],
     )
     stdout: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             "Stdout content.\n\nThis is meant for convenience. No           "
             " guarantees are made about the content.\nImplementations may"
@@ -137,7 +137,7 @@ class TesExecutorLog(CustomBaseModel):
         ),
     )
     stderr: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             "Stderr content.\n\nThis is meant for convenience. No            "
             " guarantees are made about the content.\nImplementations may"
@@ -150,7 +150,7 @@ class TesExecutorLog(CustomBaseModel):
     )
     # exit code not optional according to specs, but Funnel may return 'null'
     exit_code: Optional[int] = Field(
-        None,
+        default=None,
         description="Exit code.",
     )
 
@@ -164,14 +164,14 @@ class TesInput(CustomBaseModel):
     name: Optional[str] = None
     description: Optional[str] = None
     url: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             'REQUIRED, unless "content" is set.\n\nURL in long term        '
             " storage, for example:\n - s3://my-object-store/file1\n -        "
             "     gs://my-bucket/file2\n - file:///path/to/my/file\n -        "
             "     /path/to/my/file"
         ),
-        example="s3://my-object-store/file1",
+        examples=["s3://my-object-store/file1"],
     )
     path: str = Field(
         ...,
@@ -179,11 +179,11 @@ class TesInput(CustomBaseModel):
             "Path of the file inside the container.\nMust be an            "
             " absolute path."
         ),
-        example="/data/file1",
+        examples=["/data/file1"],
     )
     type: TesFileType
     content: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             "File content literal.\n\nImplementations should support a        "
             "    minimum of 128 KiB in this field\nand may define their own   "
@@ -195,10 +195,10 @@ class TesInput(CustomBaseModel):
 
 class TesOutput(CustomBaseModel):
     name: Optional[str] = Field(
-        None, description="User-provided name of         output file"
+        default=None, description="User-provided name of         output file"
     )
     description: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             "Optional users provided description field, can be used           "
             "  for documentation."
@@ -244,32 +244,36 @@ class TesOutputFileLog(CustomBaseModel):
             "    as a string\nbecause official JSON doesn't support int64"
             " numbers."
         ),
-        example=["1024"],
+        examples=["1024"],
     )
 
 
 class TesResources(CustomBaseModel):
     cpu_cores: Optional[int] = Field(
-        None, description="Requested number of CPUs", example=4
+        default=None, description="Requested number of CPUs", examples=[4]
     )
     preemptible: Optional[bool] = Field(
-        None,
+        default=None,
         description=(
             "Define if the task is allowed to run on preemptible            "
             " compute instances,\nfor example, AWS Spot. This option may have"
             " no            effect when utilized\non some backends that don't"
             " have the             concept of preemptible jobs."
         ),
-        example=False,
+        examples=[False],
     )
     ram_gb: Optional[float] = Field(
-        None, description="Requested RAM required in gigabytes (GB)", example=8
+        default=None,
+        description="Requested RAM required in gigabytes (GB)",
+        examples=[8]
     )
     disk_gb: Optional[float] = Field(
-        None, description="Requested disk size in gigabytes (GB)", example=40
+        default=None,
+        description="Requested disk size in gigabytes (GB)",
+        examples=[40]
     )
     zones: Optional[list[str]] = Field(
-        None,
+        default=None,
         description=(
             "Request that the task be run in these compute zones. How         "
             "   this string\nis utilized will be dependent on the backend"
@@ -278,7 +282,7 @@ class TesResources(CustomBaseModel):
             " define\npriorty queue to which the job is               "
             " assigned."
         ),
-        example="us-west-1",
+        examples=["us-west-1"],
     )
 
 
@@ -298,16 +302,16 @@ class ServiceType(CustomBaseModel):
             " namespace (e.g. your organization's reverse domain              "
             "  name)."
         ),
-        example="org.ga4gh",
+        examples=["org.ga4gh"],
     )
-    artifact: str = Field(
+    artifact: Enum = Field(
         ...,
         description=(
             "Name of the API or GA4GH specification implemented.            "
             " Official GA4GH types should be assigned as part of standards    "
             "         approval process. Custom artifacts are supported."
         ),
-        example="beacon",
+        examples=["beacon"],
     )
     version: str = Field(
         ...,
@@ -315,7 +319,7 @@ class ServiceType(CustomBaseModel):
             "Version of the API or specification. GA4GH specifications        "
             "    use semantic versioning."
         ),
-        example="1.0.0",
+        examples=["1.0.0"],
     )
 
 
@@ -323,12 +327,12 @@ class Organization(CustomBaseModel):
     name: str = Field(
         ...,
         description="Name of the organization responsible for the service",
-        example="My organization",
+        examples=["My organization"],
     )
     url: AnyUrl = Field(
         ...,
         description="URL of the website of the organization (RFC 3986 format)",
-        example="https://example.com",
+        examples=["https://example.com"],
     )
 
 
@@ -342,62 +346,62 @@ class Service(CustomBaseModel):
             " downstream aggregator             services e.g. Service"
             " Registry."
         ),
-        example="org.ga4gh.myservice",
+        examples=["org.ga4gh.myservice"],
     )
     name: str = Field(
         ...,
         description="Name of this service. Should be human readable.",
-        example="My project",
+        examples=["My project"],
     )
-    type: ServiceType
+    type: Optional[ServiceType]
     description: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             "Description of the service. Should be human readable and         "
             "    provide information about the service."
         ),
-        example="This service provides...",
+        examples=["This service provides..."],
     )
     organization: Organization = Field(
         ..., description="Organization providing the service"
     )
     contactUrl: Optional[AnyUrl] = Field(
-        None,
+        default=None,
         description=(
             "URL of the contact for the provider of this service, e.g.        "
             "    a link to a contact form (RFC 3986 format), or an email      "
             "           (RFC 2368 format)."
         ),
-        example="mailto:support@example.com",
+        examples=["mailto:support@example.com"],
     )
     documentationUrl: Optional[AnyUrl] = Field(
-        None,
+        default=None,
         description=(
             "URL of the documentation of this service             (RFC 3986"
             " format).This should help someone learn how             to use"
             " your service, including any specifics required to            "
             " access data, e.g. authentication."
         ),
-        example="https://docs.myservice.example.com",
+        examples=["https://docs.myservice.example.com"],
     )
     createdAt: Optional[datetime] = Field(
-        None,
+        default=None,
         description=(
             "Timestamp describing when the service was first deployed         "
             "   and available (RFC 3339 format)"
         ),
-        example="2019-06-04T12:58:19Z",
+        examples=["2019-06-04T12:58:19Z"],
     )
     updatedAt: Optional[datetime] = Field(
-        None,
+        default=None,
         description=(
             "Timestamp describing when the service was last updated           "
             " (RFC 3339 format)"
         ),
-        example="2019-06-04T12:58:19Z",
+        examples=["2019-06-04T12:58:19Z"],
     )
     environment: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             "Environment the service is running in. Use this to            "
             " distinguish between production, development and testing/staging "
@@ -405,7 +409,7 @@ class Service(CustomBaseModel):
             " dev, staging.                 However this is advised and not"
             " enforced."
         ),
-        example="test",
+        examples=["test"],
     )
     version: str = Field(
         ...,
@@ -416,7 +420,7 @@ class Service(CustomBaseModel):
             " should be changed                whenever the service is"
             " updated."
         ),
-        example="1.0.0",
+        examples=["1.0.0"],
     )
 
 
@@ -438,7 +442,7 @@ class TesNextTes(CustomBaseModel):
     url: str = Field(
         ...,
         description="TES server to which the task was forwarded.",
-        example="https://my.tes.instance/",
+        examples=["https://my.tes.instance/"],
     )
     id: str = Field(
         ...,
@@ -446,7 +450,7 @@ class TesNextTes(CustomBaseModel):
             "Task identifier assigned by the "
             "TES server to which the task was forwarded."
         ),
-        example="job-0012345",
+        examples=["job-0012345"],
     )
     forwarded_to: Optional[TesNextTes] = None
 
@@ -455,7 +459,7 @@ class Metadata(CustomBaseModel):
     """Create model instance for metadata."""
 
     forwarded_to: Optional[TesNextTes] = Field(
-        None,
+        default=None,
         description="TaskLog describes logging information related to a Task",
     )
 
@@ -465,21 +469,21 @@ class TesTaskLog(CustomBaseModel):
         ..., description="Logs for each executor"
     )
     metadata: Optional[Metadata] = Field(
-        None,
+        default=None,
         description=(
             "Arbitrary logging metadata included by the implementation."
         ),
-        example={"host": "worker-001", "slurmm_id": 123456},
+        examples=[{"host": "worker-001", "slurmm_id": 123456}],
     )
     start_time: Optional[str] = Field(
-        None,
+        default=None,
         description="When the task started, in RFC 3339 format.",
-        example="2020-10-02T10:00:00-05:00",
+        examples=["2020-10-02T10:00:00-05:00"],
     )
     end_time: Optional[str] = Field(
-        None,
+        default=None,
         description="When the task ended, in RFC 3339 format.",
-        example="2020-10-02T11:00:00-05:00",
+        examples=["2020-10-02T11:00:00-05:00"],
     )
     outputs: list[TesOutputFileLog] = Field(
         ...,
@@ -489,7 +493,7 @@ class TesTaskLog(CustomBaseModel):
         ),
     )
     system_logs: Optional[list[str]] = Field(
-        None,
+        default=None,
         description=(
             "System logs are any logs the system decides are relevant,        "
             "    \nwhich are not tied directly to an Executor"
@@ -505,17 +509,17 @@ class TesTaskLog(CustomBaseModel):
 
 
 class TesServiceType(ServiceType):
-    artifact: Artifact = Field(..., example="tes")
+    artifact: Artifact = Field(..., examples=["tes"])
 
 
 class TesServiceInfo(Service):
     storage: Optional[list[str]] = Field(
-        None,
+        default=None,
         description=(
             "Lists some, but not necessarily all, storage locations           "
             "  supported\nby the service."
         ),
-        example=[
+        examples=[
             "file:///path/to/local/funnel-storage",
             "s3://ohsu-compbio-funnel/storage",
         ],
@@ -525,35 +529,41 @@ class TesServiceInfo(Service):
 
 class TesTask(CustomBaseModel):
     id: Optional[str] = Field(
-        None,
+        default=None,
         description="Task identifier assigned by the server.",
-        example="job-0012345",
+        examples=["job-0012345"],
     )
     state: Optional[TesState] = None
-    name: Optional[str] = Field(None, description="User-provided task name.")
+    name: Optional[str] = Field(
+        default=None,
+        description="User-provided task name."
+    )
     description: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             "Optional user-provided description of task for           "
             " documentation purposes."
         ),
     )
     inputs: Optional[list[TesInput]] = Field(
-        None,
+        default=None,
         description=(
             "Input files that will be used by the task. Inputs will be        "
             "    downloaded\nand mounted into the executor container as"
             " defined by                 the task request\ndocument."
         ),
-        example=[{"url": "s3://my-object-store/file1", "path": "/data/file1"}],
+        examples=[[{
+                    "url": "s3://my-object-store/file1",
+                    "path": "/data/file1"
+                }]]
     )
     outputs: Optional[list[TesOutput]] = Field(
-        None,
+        default=None,
         description=(
             "Output files.\nOutputs will be uploaded from the executor        "
             "    container to long-term storage."
         ),
-        example=[
+        examples=[
             {
                 "path": "/data/outfile",
                 "url": "s3://my-object-store/outfile-1",
@@ -563,7 +573,7 @@ class TesTask(CustomBaseModel):
     )
     resources: Optional[TesResources] = None
     executors: list[TesExecutor] = Field(
-        [TesExecutor],
+        default=[TesExecutor],
         description=(
             "An array of executors to be run. Each of the executors           "
             " will run one\nat a time sequentially. Each executor is a"
@@ -575,7 +585,7 @@ class TesTask(CustomBaseModel):
         ),
     )
     volumes: Optional[list[str]] = Field(
-        None,
+        default=None,
         description=(
             "Volumes are directories which may be used to share data          "
             "  between\nExecutors. Volumes are initialized as empty"
@@ -588,10 +598,10 @@ class TesTask(CustomBaseModel):
             " a `docker run -v` flag where\nthe container path is            "
             " the same for each executor)."
         ),
-        example=["/vol/A/"],
+        examples=[["/vol/A/"]],
     )
     tags: Optional[dict[str, str]] = Field(
-        None,
+        default=None,
         description=(
             "A key-value map of arbitrary tags. These can be used to          "
             "   store meta-data\nand annotations about a task."
@@ -599,10 +609,10 @@ class TesTask(CustomBaseModel):
             ' "cwl-01234",\n                  "PROJECT_GROUP" : "alice-lab"\n '
             " }\n}\n```"
         ),
-        example={"WORKFLOW_ID": "cwl-01234", "PROJECT_GROUP": "alice-lab"},
+        examples=[{"WORKFLOW_ID": "cwl-01234", "PROJECT_GROUP": "alice-lab"}],
     )
     logs: Optional[list[TesTaskLog]] = Field(
-        None,
+        default=None,
         description=(
             "Task logging information.\nNormally, this will contain           "
             "  only one entry, but in the case where\na task fails and is     "
@@ -610,12 +620,12 @@ class TesTask(CustomBaseModel):
         ),
     )
     creation_time: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             "Date + time the task was created, in RFC 3339 format.\n          "
             "   This is set by the system, not the client."
         ),
-        example="2020-10-02T10:00:00-05:00",
+        examples=["2020-10-02T10:00:00-05:00"],
     )
 
     class Config:
@@ -635,7 +645,7 @@ class TesListTasksResponse(CustomBaseModel):
         ),
     )
     next_page_token: Optional[str] = Field(
-        None,
+        default=None,
         description=(
             "Token used to return the next page of results. This value        "
             "    can be used\nin the `page_token` field of the next ListTasks "
@@ -709,7 +719,7 @@ class DbDocument(CustomBaseModel):
     """
 
     task: TesTask = TesTask()
-    task_original: TesTask = TesTask(executors=[])
+    task_original: TesTask = TesTask(executors=[])  # type: ignore
     user_id: Optional[str] = None
     worker_id: str = ""
     basic_auth: BasicAuth = BasicAuth()
diff --git a/pro_tes/ga4gh/tes/service_info.py b/pro_tes/ga4gh/tes/service_info.py
index a9c1fc0..f9a24c8 100644
--- a/pro_tes/ga4gh/tes/service_info.py
+++ b/pro_tes/ga4gh/tes/service_info.py
@@ -24,7 +24,7 @@ class ServiceInfo:
     def __init__(self) -> None:
         """Construct class instance."""
         self.db_client: Collection = (
-            current_app.config.foca.db.dbs["taskStore"]
+            current_app.config.foca.db.dbs["taskStore"]  # type: ignore
             .collections["service_info"]
             .client
         )
@@ -65,7 +65,7 @@ def init_service_info_from_config(self) -> None:
 
         Set service info only if it does not yet exist.
         """
-        service_info_conf = current_app.config.foca.serviceInfo
+        service_info_conf = current_app.config.foca.serviceInfo  # type: ignore
         try:
             service_info_db = self.get_service_info()
         except NotFound:
diff --git a/pro_tes/ga4gh/tes/task_runs.py b/pro_tes/ga4gh/tes/task_runs.py
index 8bfccc3..308aec1 100644
--- a/pro_tes/ga4gh/tes/task_runs.py
+++ b/pro_tes/ga4gh/tes/task_runs.py
@@ -16,6 +16,7 @@
 import requests
 import tes  # type: ignore
 from tes.models import Task  # type: ignore
+from pro_tes.ga4gh.tes.models import Metadata
 
 from pro_tes.exceptions import (
     BadRequest,
@@ -57,7 +58,7 @@ class TaskRuns:
 
     def __init__(self) -> None:
         """Construct object instance."""
-        self.foca_config: Config = current_app.config.foca
+        self.foca_config: Config = current_app.config.foca  # type: ignore
         self.db_client: Collection = (
             self.foca_config.db.dbs["taskStore"].collections["tasks"].client
         )
@@ -84,7 +85,9 @@ def create_task(  # pylint: disable=too-many-statements,too-many-branches
 
         # apply middlewares
         mw_handler = MiddlewareHandler()
-        mw_handler.set_middlewares(paths=current_app.config.foca.middlewares)
+        mw_handler.set_middlewares(
+            paths=current_app.config.foca.middlewares   # type: ignore
+        )
         logger.debug(f"Middlewares registered: {mw_handler.middlewares}")
         request_modified = mw_handler.apply_middlewares(request=request)
 
@@ -276,7 +279,7 @@ def list_tasks(self, **kwargs) -> dict:
         view = kwargs.get("view", "BASIC")
         projection = self._set_projection(view=view)
 
-        name_prefix: str = kwargs.get("name_prefix")
+        name_prefix: str = str(kwargs.get("name_prefix"))
 
         if name_prefix is not None:
             filter_dict["task_original.name"] = {"$regex": f"^{name_prefix}"}
@@ -355,7 +358,7 @@ def cancel_task(self, id: str, **kwargs) -> dict:
         if document is None:
             logger.error(f"task '{id}' not found.")
             raise TaskNotFound
-        db_document = DbDocument(**document)
+        db_document: DbDocument = DbDocument(**document)
 
         if db_document.task.state in States.CANCELABLE:
             db_connector = DbDocumentConnector(
@@ -366,10 +369,27 @@ def cancel_task(self, id: str, **kwargs) -> dict:
                 f"{db_document.tes_endpoint.host.rstrip('/')}/"
                 f"{db_document.tes_endpoint.base_path.strip('/')}"
             )
+
+            _logs = db_document.task.logs
+            assert isinstance(
+                _logs,
+                (list, tuple)
+            ), "task logs is not indexable"
+
+            _metadata = _logs[0].metadata
+            assert isinstance(
+                _metadata,
+                Metadata
+            ), "task metadata is None"
+
             if self.store_logs:
-                task_id = db_document.task.logs[0].metadata.forwarded_to.id
+                assert (
+                    _metadata.forwarded_to is not None
+                ), "link to next TES is None"
+                task_id = _metadata.forwarded_to.id
             else:
-                task_id = db_document.task.logs[0].metadata["remote_task_id"]
+                task_id = _metadata["remote_task_id"]   # type: ignore
+
             logger.info(
                 "Trying to cancel task with task identifier"
                 f" '{task_id}' and worker job"
@@ -421,6 +441,7 @@ def _write_doc_to_db(
             except DuplicateKeyError:
                 continue
             assert document is not None
+            assert document.task.id is not None
             return document.task.id, document.worker_id
         raise DuplicateKeyError("Could not insert document into database.")
 
@@ -603,10 +624,13 @@ def _update_task_metadata(
         Returns:
             The updated database document.
         """
-        for logs in db_document.task.logs:
+        assert db_document.task.logs is not None
+        logs: list[TesTaskLog] = db_document.task.logs
+        for log in logs:
+            assert log.metadata is not None
             tesNextTes_obj = TesNextTes(id=remote_task_id, url=tes_url)
-            if logs.metadata.forwarded_to is None:
-                logs.metadata.forwarded_to = tesNextTes_obj
+            if log.metadata.forwarded_to is None:
+                log.metadata.forwarded_to = tesNextTes_obj
         return db_document
 
     @staticmethod
diff --git a/pro_tes/plugins/middlewares/task_distribution/distance.py b/pro_tes/plugins/middlewares/task_distribution/distance.py
index 9f69b28..505a701 100644
--- a/pro_tes/plugins/middlewares/task_distribution/distance.py
+++ b/pro_tes/plugins/middlewares/task_distribution/distance.py
@@ -228,7 +228,7 @@ def _get_ips(*args: AnyUrl) -> dict[AnyUrl, str]:
         ips: dict[AnyUrl, str] = {}
         for uri in args:
             try:
-                ips[uri] = gethostbyname(urlparse(strip_auth(uri)).netloc)
+                ips[uri] = gethostbyname(urlparse(strip_auth(str(uri))).netloc)
             except gaierror as exc:
                 raise MiddlewareException(
                     f"Could not determine IP address for URI: {uri}"
diff --git a/pro_tes/tasks/track_task_progress.py b/pro_tes/tasks/track_task_progress.py
index 3173515..09b6fa0 100644
--- a/pro_tes/tasks/track_task_progress.py
+++ b/pro_tes/tasks/track_task_progress.py
@@ -50,7 +50,7 @@ def task__track_task_progress(  # pylint: disable=too-many-arguments
         user: User-name for basic authentication.
         password: Password for basic authentication.
     """
-    foca_config: Config = current_app.config.foca
+    foca_config: Config = current_app.config.foca   # type: ignore
     controller_config: dict = foca_config.controllers["post_task"]
 
     # create database client
@@ -110,6 +110,8 @@ def task__track_task_progress(  # pylint: disable=too-many-arguments
 
     # updating task after task is finished
     document.task.state = task_converted.state
+    assert task_converted.logs is not None
+    assert document.task.logs is not None
     for index, logs in enumerate(task_converted.logs):
         document.task.logs[index].logs = logs.logs
         document.task.logs[index].outputs = logs.outputs
diff --git a/requirements_dev.txt b/requirements_dev.txt
index f6f1bfe..6674972 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -7,3 +7,5 @@ mypy>=0.990
 pylint>=2.15.5
 pytest>=7.2.0
 python-semantic-release>=7.32.2
+mypy>=1.8.0
+types-python-dateutil>=2.8.19.20240106
\ No newline at end of file