diff --git a/src/taskgraph/transforms/cached_tasks.py b/src/taskgraph/transforms/cached_tasks.py
index 57a55dffb..8f840c2dd 100644
--- a/src/taskgraph/transforms/cached_tasks.py
+++ b/src/taskgraph/transforms/cached_tasks.py
@@ -50,7 +50,7 @@ def format_task_digest(cached_task):
 
 
 @transforms.add
-def cache_task(config, tasks):
+async def cache_task(config, tasks):
     if taskgraph.fast:
         for task in tasks:
             yield task
@@ -61,7 +61,7 @@ def cache_task(config, tasks):
         if "cached_task" in task.attributes:
             digests[task.label] = format_task_digest(task.attributes["cached_task"])
 
-    for task in order_tasks(config, tasks):
+    for task in order_tasks(config, [t async for t in tasks]):
         cache = task.pop("cache", None)
         if cache is None:
             yield task
diff --git a/src/taskgraph/transforms/chunking.py b/src/taskgraph/transforms/chunking.py
index 31d7eff82..b6bac16d7 100644
--- a/src/taskgraph/transforms/chunking.py
+++ b/src/taskgraph/transforms/chunking.py
@@ -50,8 +50,8 @@
 
 
 @transforms.add
-def chunk_tasks(config, tasks):
-    for task in tasks:
+async def chunk_tasks(config, tasks):
+    async for task in tasks:
         chunk_config = task.pop("chunk", None)
         if not chunk_config:
             yield task
diff --git a/src/taskgraph/transforms/code_review.py b/src/taskgraph/transforms/code_review.py
index bdb655b97..a6bfa9538 100644
--- a/src/taskgraph/transforms/code_review.py
+++ b/src/taskgraph/transforms/code_review.py
@@ -12,8 +12,8 @@
 
 
 @transforms.add
-def add_dependencies(config, jobs):
-    for job in jobs:
+async def add_dependencies(config, jobs):
+    async for job in jobs:
         job.setdefault("soft-dependencies", [])
         job["soft-dependencies"] += [
             dep_task.label
diff --git a/src/taskgraph/transforms/docker_image.py b/src/taskgraph/transforms/docker_image.py
index d0c5b9c97..17ba3e7fb 100644
--- a/src/taskgraph/transforms/docker_image.py
+++ b/src/taskgraph/transforms/docker_image.py
@@ -65,7 +65,7 @@
 
 
 @transforms.add
-def fill_template(config, tasks):
+async def fill_template(config, tasks):
     available_packages = set()
     for task in config.kind_dependencies_tasks.values():
         if task.kind != "packages":
@@ -75,13 +75,11 @@ def fill_template(config, tasks):
 
     context_hashes = {}
 
-    tasks = list(tasks)
-
     if not taskgraph.fast and config.write_artifacts:
         if not os.path.isdir(CONTEXTS_DIR):
             os.makedirs(CONTEXTS_DIR)
 
-    for task in tasks:
+    async for task in tasks:
         image_name = task.pop("name")
         job_symbol = task.pop("symbol", None)
         args = task.pop("args", {})
diff --git a/src/taskgraph/transforms/fetch.py b/src/taskgraph/transforms/fetch.py
index bcb8ff38a..e24c0183f 100644
--- a/src/taskgraph/transforms/fetch.py
+++ b/src/taskgraph/transforms/fetch.py
@@ -78,9 +78,9 @@ def wrap(func):
 
 
 @transforms.add
-def process_fetch_job(config, jobs):
+async def process_fetch_job(config, jobs):
     # Converts fetch-url entries to the job schema.
-    for job in jobs:
+    async for job in jobs:
         typ = job["fetch"]["type"]
         name = job["name"]
         fetch = job.pop("fetch")
@@ -103,7 +103,7 @@ def configure_fetch(config, typ, name, fetch):
 
 
 @transforms.add
-def make_task(config, jobs):
+async def make_task(config, jobs):
     # Fetch tasks are idempotent and immutable. Have them live for
     # essentially forever.
     if config.params["level"] == "3":
@@ -111,7 +111,7 @@ def make_task(config, jobs):
     else:
         expires = "28 days"
 
-    for job in jobs:
+    async for job in jobs:
         name = job["name"]
         artifact_prefix = job.get("artifact-prefix", "public")
         env = job.get("env", {})
diff --git a/src/taskgraph/transforms/from_deps.py b/src/taskgraph/transforms/from_deps.py
index 337d68e4b..c476c1038 100644
--- a/src/taskgraph/transforms/from_deps.py
+++ b/src/taskgraph/transforms/from_deps.py
@@ -113,8 +113,8 @@
 
 
 @transforms.add
-def from_deps(config, tasks):
-    for task in tasks:
+async def from_deps(config, tasks):
+    async for task in tasks:
         # Setup and error handling.
         from_deps = task.pop("from-deps")
         kind_deps = config.config.get("kind-dependencies", [])
diff --git a/src/taskgraph/transforms/job/__init__.py b/src/taskgraph/transforms/job/__init__.py
index d86eff3ef..5ad6def7d 100644
--- a/src/taskgraph/transforms/job/__init__.py
+++ b/src/taskgraph/transforms/job/__init__.py
@@ -112,8 +112,8 @@
 
 
 @transforms.add
-def rewrite_when_to_optimization(config, jobs):
-    for job in jobs:
+async def rewrite_when_to_optimization(config, jobs):
+    async for job in jobs:
         when = job.pop("when", {})
         if not when:
             yield job
@@ -132,8 +132,8 @@ def rewrite_when_to_optimization(config, jobs):
 
 
 @transforms.add
-def set_implementation(config, jobs):
-    for job in jobs:
+async def set_implementation(config, jobs):
+    async for job in jobs:
         impl, os = worker_type_implementation(config.graph_config, job["worker-type"])
         if os:
             job.setdefault("tags", {})["os"] = os
@@ -148,8 +148,8 @@ def set_implementation(config, jobs):
 
 
 @transforms.add
-def set_label(config, jobs):
-    for job in jobs:
+async def set_label(config, jobs):
+    async for job in jobs:
         if "label" not in job:
             if "name" not in job:
                 raise Exception("job has neither a name nor a label")
@@ -160,8 +160,8 @@ def set_label(config, jobs):
 
 
 @transforms.add
-def add_resource_monitor(config, jobs):
-    for job in jobs:
+async def add_resource_monitor(config, jobs):
+    async for job in jobs:
         if job.get("attributes", {}).get("resource-monitor"):
             worker_implementation, worker_os = worker_type_implementation(
                 config.graph_config, job["worker-type"]
@@ -204,13 +204,13 @@ def get_attribute(dict, key, attributes, attribute_name):
 
 
 @transforms.add
-def use_fetches(config, jobs):
+async def use_fetches(config, jobs):
     artifact_names = {}
     aliases = {}
     extra_env = {}
 
+    jobs = [j async for j in jobs]
     if config.kind in ("toolchain", "fetch"):
-        jobs = list(jobs)
         for job in jobs:
             run = job.get("run", {})
             label = job["label"]
@@ -353,12 +353,12 @@ def cmp_artifacts(a):
 
 
 @transforms.add
-def make_task_description(config, jobs):
+async def make_task_description(config, jobs):
     """Given a build description, create a task description"""
     # import plugin modules first, before iterating over jobs
     import_sibling_modules(exceptions=("common.py",))
 
-    for job in jobs:
+    async for job in jobs:
         # always-optimized tasks never execute, so have no workdir
         if job["worker"]["implementation"] in ("docker-worker", "generic-worker"):
             job["run"].setdefault("workdir", "/builds/worker")
diff --git a/src/taskgraph/transforms/notify.py b/src/taskgraph/transforms/notify.py
index a61e7999c..8e9b4229a 100644
--- a/src/taskgraph/transforms/notify.py
+++ b/src/taskgraph/transforms/notify.py
@@ -140,8 +140,8 @@ def _convert_content(content):
 
 
 @transforms.add
-def add_notifications(config, tasks):
-    for task in tasks:
+async def add_notifications(config, tasks):
+    async for task in tasks:
         label = "{}-{}".format(config.kind, task["name"])
         if "notifications" in task:
             notify = _convert_legacy(config, task.pop("notifications"), label)
diff --git a/src/taskgraph/transforms/task.py b/src/taskgraph/transforms/task.py
index c55de7851..b7f20fdff 100644
--- a/src/taskgraph/transforms/task.py
+++ b/src/taskgraph/transforms/task.py
@@ -831,11 +831,11 @@ def build_dummy_payload(config, task, task_def):
 
 
 @transforms.add
-def set_implementation(config, tasks):
+async def set_implementation(config, tasks):
     """
     Set the worker implementation based on the worker-type alias.
     """
-    for task in tasks:
+    async for task in tasks:
         worker = task.setdefault("worker", {})
         if "implementation" in task["worker"]:
             yield task
@@ -855,8 +855,8 @@ def set_implementation(config, tasks):
 
 
 @transforms.add
-def set_defaults(config, tasks):
-    for task in tasks:
+async def set_defaults(config, tasks):
+    async for task in tasks:
         task.setdefault("always-target", False)
         task.setdefault("optimization", None)
         task.setdefault("needs-sccache", False)
@@ -899,8 +899,8 @@ def set_defaults(config, tasks):
 
 
 @transforms.add
-def task_name_from_label(config, tasks):
-    for task in tasks:
+async def task_name_from_label(config, tasks):
+    async for task in tasks:
         if "label" not in task:
             if "name" not in task:
                 raise Exception("task has neither a name nor a label")
@@ -911,8 +911,8 @@ def task_name_from_label(config, tasks):
 
 
 @transforms.add
-def validate(config, tasks):
-    for task in tasks:
+async def validate(config, tasks):
+    async for task in tasks:
         validate_schema(
             task_description_schema,
             task,
@@ -949,8 +949,8 @@ def add_generic_index_routes(config, task):
 
 
 @transforms.add
-def process_treeherder_metadata(config, tasks):
-    for task in tasks:
+async def process_treeherder_metadata(config, tasks):
+    async for task in tasks:
         routes = task.get("routes", [])
         extra = task.get("extra", {})
         task_th = task.get("treeherder")
@@ -1021,8 +1021,8 @@ def process_treeherder_metadata(config, tasks):
 
 
 @transforms.add
-def add_index_routes(config, tasks):
-    for task in tasks:
+async def add_index_routes(config, tasks):
+    async for task in tasks:
         index = task.get("index", {})
 
         # The default behavior is to rank tasks according to their tier
@@ -1053,8 +1053,8 @@ def add_index_routes(config, tasks):
 
 
 @transforms.add
-def build_task(config, tasks):
-    for task in tasks:
+async def build_task(config, tasks):
+    async for task in tasks:
         level = str(config.params["level"])
 
         provisioner_id, worker_type = get_worker_type(
@@ -1215,24 +1215,24 @@ def build_task(config, tasks):
 
 
 @transforms.add
-def add_github_checks(config, tasks):
+async def add_github_checks(config, tasks):
     """
     For git repositories, add checks route to all tasks.
 
     This will be replaced by a configurable option in the future.
     """
     if config.params["repository_type"] != "git":
-        for task in tasks:
+        async for task in tasks:
             yield task
 
-    for task in tasks:
+    async for task in tasks:
         task["task"]["routes"].append("checks")
         yield task
 
 
 @transforms.add
-def chain_of_trust(config, tasks):
-    for task in tasks:
+async def chain_of_trust(config, tasks):
+    async for task in tasks:
         if task["task"].get("payload", {}).get("features", {}).get("chainOfTrust"):
             image = task.get("dependencies", {}).get("docker-image")
             if image:
@@ -1246,12 +1246,12 @@ def chain_of_trust(config, tasks):
 
 
 @transforms.add
-def check_task_identifiers(config, tasks):
+async def check_task_identifiers(config, tasks):
     """Ensures that all tasks have well defined identifiers:
     ``^[a-zA-Z0-9_-]{1,38}$``
     """
     e = re.compile("^[a-zA-Z0-9_-]{1,38}$")
-    for task in tasks:
+    async for task in tasks:
         for attrib in ("workerType", "provisionerId"):
             if not e.match(task["task"][attrib]):
                 raise Exception(
@@ -1263,9 +1263,9 @@ def check_task_identifiers(config, tasks):
 
 
 @transforms.add
-def check_task_dependencies(config, tasks):
+async def check_task_dependencies(config, tasks):
     """Ensures that tasks don't have more than 100 dependencies."""
-    for task in tasks:
+    async for task in tasks:
         number_of_dependencies = (
             len(task["dependencies"])
             + len(task["if-dependencies"])
@@ -1311,7 +1311,7 @@ def check_caches_are_volumes(task):
 
 
 @transforms.add
-def check_run_task_caches(config, tasks):
+async def check_run_task_caches(config, tasks):
     """Audit for caches requiring run-task.
 
     run-task manages caches in certain ways. If a cache managed by run-task
@@ -1336,7 +1336,7 @@ def check_run_task_caches(config, tasks):
 
     suffix = _run_task_suffix()
 
-    for task in tasks:
+    async for task in tasks:
         payload = task["task"].get("payload", {})
         command = payload.get("command") or [""]
 
diff --git a/src/taskgraph/transforms/task_context.py b/src/taskgraph/transforms/task_context.py
index 5c7ed6af8..14db94dda 100644
--- a/src/taskgraph/transforms/task_context.py
+++ b/src/taskgraph/transforms/task_context.py
@@ -81,8 +81,8 @@
 
 
 @transforms.add
-def render_task(config, jobs):
-    for job in jobs:
+async def render_task(config, jobs):
+    async for job in jobs:
         sub_config = job.pop("task-context")
         params_context = {}
         for var, path in sub_config.pop("from-parameters", {}).items():