diff --git a/cmd/actionExecute.go b/cmd/actionExecute.go
index 565cd81..793018b 100644
--- a/cmd/actionExecute.go
+++ b/cmd/actionExecute.go
@@ -91,7 +91,7 @@ func actionExecute(
 
 	db := openAndMigrateDb()
 
-	state, envs, argv, postProcess, err := core.GetSourceActionInputs(db, source, action)
+	state, envs, argv, err := core.GetSourceActionInputs(db, source, action)
 	if err != nil {
 		log.Fatalf("error: failed to load data for %s: %v", source, err)
 	}
@@ -109,7 +109,7 @@ func actionExecute(
 		}
 	}
 
-	newItem, newState, errItem, err := core.ExecuteItemAction(item, argv, envs, state, duration, postProcess)
+	newItem, newState, errItem, err := core.ExecuteItemAction(item, argv, envs, state, duration)
 	if err != nil {
 		core.AddErrorItem(db, errItem)
 		log.Fatalf("error executing %s: %v", action, err)
diff --git a/cmd/sourceFetch.go b/cmd/sourceFetch.go
index 6ef6bba..e59dbf5 100644
--- a/cmd/sourceFetch.go
+++ b/cmd/sourceFetch.go
@@ -55,12 +55,12 @@ func sourceFetch(source string, format string, timeout string, dryRun bool) {
 
 	db := openAndMigrateDb()
 
-	state, envs, argv, postProcess, err := core.GetSourceActionInputs(db, source, "fetch")
+	state, envs, argv, err := core.GetSourceActionInputs(db, source, "fetch")
 	if err != nil {
 		log.Fatalf("error: failed to load data for %s: %v", source, err)
 	}
 
-	items, newState, errItem, err := core.Execute(source, argv, envs, state, "", duration, postProcess)
+	items, newState, errItem, err := core.Execute(source, argv, envs, state, "", duration)
 	if err != nil {
 		core.AddErrorItem(db, errItem)
 		log.Fatalf("error: failed to execute fetch: %v", err)
diff --git a/cmd/sourceTest.go b/cmd/sourceTest.go
index 5bf5d01..e356e9e 100644
--- a/cmd/sourceTest.go
+++ b/cmd/sourceTest.go
@@ -45,7 +45,7 @@ func sourceTest(env []string, format string, timeout string, cmd []string) {
 		log.Fatalf("error: invalid duration: %v", err)
 	}
 
-	items, state, _, err := core.Execute("test", cmd, env, nil, "", duration, nil)
+	items, state, _, err := core.Execute("test", cmd, env, nil, "", duration)
 	log.Printf("returned %d items", len(items))
 	log.Printf("wrote %d bytes of state", len(state))
 	if err != nil {
diff --git a/core/cron.go b/core/cron.go
index 3c4d007..6904d81 100644
--- a/core/cron.go
+++ b/core/cron.go
@@ -203,13 +203,13 @@ func fetchReadySources(db DB) {
 		}
 		log.Printf("%s: fetching", schedule.Source)
 
-		state, envs, argv, postProcess, err := GetSourceActionInputs(db, schedule.Source, "fetch")
+		state, envs, argv, err := GetSourceActionInputs(db, schedule.Source, "fetch")
 		if err != nil {
 			log.Printf("error: failed to load data for %s: %v", schedule.Source, err)
 			continue
 		}
 
-		items, newState, errItem, err := Execute(schedule.Source, argv, envs, state, "", DefaultTimeout, postProcess)
+		items, newState, errItem, err := Execute(schedule.Source, argv, envs, state, "", DefaultTimeout)
 		if err != nil {
 			AddErrorItem(db, errItem)
 			log.Printf("error: failed to execute fetch: %v", err)
diff --git a/core/execute.go b/core/execute.go
index 7c45dc1..3b3a7a4 100644
--- a/core/execute.go
+++ b/core/execute.go
@@ -62,7 +62,6 @@ func Execute(
 	state []byte,
 	input string,
 	timeout time.Duration,
-	postProcess func(item Item) Item,
 ) (
 	items []Item,
 	newState []byte,
@@ -193,9 +192,6 @@ monitor:
 				}
 				itemIds[item.Id] = true
 
-				if postProcess != nil {
-					item = postProcess(item)
-				}
 				item.Active = true   // These fields aren't up to
 				item.Created = 0     // the action to set and
 				item.Source = source // shouldn't be overrideable
@@ -269,7 +265,6 @@ func ExecuteItemAction(
 	env []string,
 	state []byte,
 	timeout time.Duration,
-	postProcess func(item Item) Item,
 ) (
 	newItem Item,
 	newState []byte,
@@ -285,7 +280,7 @@ func ExecuteItemAction(
 		return
 	}
 
-	res, newState, errItem, err := Execute(item.Source, argv, env, state, string(itemJson), timeout, postProcess)
+	res, newState, errItem, err := Execute(item.Source, argv, env, state, string(itemJson), timeout)
 	if err != nil {
 		err = fmt.Errorf("failed to execute action for %s/%s: %v", item.Source, item.Id, err)
 		errItem = makeErrorItem(err, nil)
diff --git a/core/execute_test.go b/core/execute_test.go
index 0078d26..a8761e4 100644
--- a/core/execute_test.go
+++ b/core/execute_test.go
@@ -26,7 +26,7 @@ func TestExecute(t *testing.T) {
 		}
 	}
 	execute := func(argv []string) ([]Item, error) {
-		item, _, _, err := Execute("_", argv, nil, nil, "", time.Minute, nil)
+		item, _, _, err := Execute("_", argv, nil, nil, "", time.Minute)
 		return item, err
 	}
 
@@ -49,7 +49,7 @@ func TestExecute(t *testing.T) {
 	})
 
 	t.Run("Timeout", func(t *testing.T) {
-		res, _, _, err := Execute("_", []string{"sleep", "10"}, nil, nil, "", time.Millisecond, nil)
+		res, _, _, err := Execute("_", []string{"sleep", "10"}, nil, nil, "", time.Millisecond)
 		assertNotNil(t, err)
 		assertLen(t, res, 0)
 	})
@@ -64,7 +64,7 @@ func TestExecute(t *testing.T) {
 	})
 
 	t.Run("ReadFromStdin", func(t *testing.T) {
-		res, _, _, err := Execute("_", []string{"jq", "-cR", `{id: .}`}, nil, nil, "bar", time.Minute, nil)
+		res, _, _, err := Execute("_", []string{"jq", "-cR", `{id: .}`}, nil, nil, "bar", time.Minute)
 		assertNil(t, err)
 		assertLen(t, res, 1)
 		if res[0].Id != "bar" {
@@ -73,7 +73,7 @@ func TestExecute(t *testing.T) {
 	})
 
 	t.Run("SetEnv", func(t *testing.T) {
-		res, _, _, err := Execute("_", []string{"jq", "-cn", `{id: env.HELLO}`}, []string{"HELLO=baz"}, nil, "", time.Minute, nil)
+		res, _, _, err := Execute("_", []string{"jq", "-cn", `{id: env.HELLO}`}, []string{"HELLO=baz"}, nil, "", time.Minute)
 		assertNil(t, err)
 		assertLen(t, res, 1)
 		if res[0].Id != "baz" {
@@ -160,7 +160,7 @@ func TestExecute(t *testing.T) {
 
 	t.Run("ReadState", func(t *testing.T) {
 		argv := []string{"sh", "-c", `cat $STATE_PATH | jq -cR '{id: "greeting", title: .} | .title = "Hello " + .title'`}
-		res, _, _, err := Execute("_", argv, nil, []byte("world"), "", time.Minute, nil)
+		res, _, _, err := Execute("_", argv, nil, []byte("world"), "", time.Minute)
 		assertNil(t, err)
 		assertLen(t, res, 1)
 		if res[0].Title != "Hello world" {
@@ -170,7 +170,7 @@ func TestExecute(t *testing.T) {
 
 	t.Run("WriteState", func(t *testing.T) {
 		argv := []string{"sh", "-c", `printf "Hello world" > $STATE_PATH; jq -cn '{id: "test"}'`}
-		res, newState, _, err := Execute("_", argv, nil, nil, "", time.Minute, nil)
+		res, newState, _, err := Execute("_", argv, nil, nil, "", time.Minute)
 		assertNil(t, err)
 		assertLen(t, res, 1)
 		if string(newState) != "Hello world" {
@@ -178,22 +178,9 @@ func TestExecute(t *testing.T) {
 		}
 	})
 
-	t.Run("PostprocessSetTtl", func(t *testing.T) {
-		argv := []string{"jq", "-cn", `{id: "foo"}`}
-		res, _, _, err := Execute("_", argv, nil, nil, "", time.Minute, func(item Item) Item {
-			item.Ttl = 123456
-			return item
-		})
-		assertNil(t, err)
-		assertLen(t, res, 1)
-		if res[0].Ttl != 123456 {
-			t.Fatalf("expected ttl to be set to 123456, got %d", res[0].Ttl)
-		}
-	})
-
 	t.Run("ErrorItem", func(t *testing.T) {
 		argv := []string{"sh", "-c", `echo 1>&2 Hello; jq -cn '{id: "box"}'; echo 1>&2 World; printf '{"whoops": "my bad"}'`}
-		_, _, errItem, err := Execute("test", argv, nil, nil, "", time.Minute, nil)
+		_, _, errItem, err := Execute("test", argv, nil, nil, "", time.Minute)
 		assertNotNil(t, err)
 		if errItem.Id == "" {
 			t.Error("missing erritem id")
diff --git a/core/source.go b/core/source.go
index 31bc8e8..907373e 100644
--- a/core/source.go
+++ b/core/source.go
@@ -138,27 +138,21 @@ func GetSourceActionInputs(
 	state []byte,
 	envs []string,
 	argv []string,
-	postProcess func(Item) Item,
 	err error,
 ) {
 	state, err = GetState(db, source)
 	if err != nil {
-		return nil, nil, nil, nil, fmt.Errorf("failed to load state for %s: %v", source, err)
+		return nil, nil, nil, fmt.Errorf("failed to load state for %s: %v", source, err)
 	}
 
 	envs, err = GetEnvs(db, source)
 	if err != nil {
-		return nil, nil, nil, nil, fmt.Errorf("failed to get envs for %s: %v", source, err)
+		return nil, nil, nil, fmt.Errorf("failed to get envs for %s: %v", source, err)
 	}
 
 	argv, err = GetArgvForAction(db, source, action)
 	if err != nil {
-		return nil, nil, nil, nil, fmt.Errorf("failed to get %s action for %s: %v", action, source, err)
-	}
-
-	postProcess, err = GetSourcePostProcessor(db, source)
-	if err != nil {
-		return nil, nil, nil, nil, fmt.Errorf("failed to get %s post-processor: %v", source, err)
+		return nil, nil, nil, fmt.Errorf("failed to get %s action for %s: %v", action, source, err)
 	}
 	return
 }
@@ -191,6 +185,21 @@ func updateWithFetchedItemsTx(
 	items []Item,
 	now time.Time,
 ) (int, int, error) {
+	envs, err := GetEnvs(db, source)
+	if err != nil {
+		return 0, 0, fmt.Errorf("failed to get envs for %s: %v", source, err)
+	}
+
+	postProcess, err := GetSourcePostProcessor(db, source)
+	if err != nil {
+		return 0, 0, fmt.Errorf("failed to get post-processor for %s: %v", source, err)
+	}
+
+	onCreateArgv, err := GetArgvForAction(db, source, "on_create")
+	if err != nil {
+		log.Printf("error: failed to get on_create action for %s: %v", source, err)
+	}
+
 	// Get all existing items
 	existingItems, err := GetAllItemsForSource(db, source, 0, -1)
 	if err != nil {
@@ -214,6 +223,13 @@ func updateWithFetchedItemsTx(
 		}
 	}
 
+	// Apply post-processing to the new items
+	if postProcess != nil {
+		for i := range newItems {
+			newItems[i] = postProcess(newItems[i])
+		}
+	}
+
 	// Bulk insert the new items
 	if err = AddItems(db, newItems); err != nil {
 		return 0, 0, err
@@ -227,25 +243,14 @@ func updateWithFetchedItemsTx(
 		return 0, 0, err
 	}
 
-	envs, err := GetEnvs(db, source)
-	if err != nil {
-		return 0, 0, fmt.Errorf("failed to get envs for %s: %v", source, err)
-	}
-
-	postProcess, err := GetSourcePostProcessor(db, source)
-	if err != nil {
-		return 0, 0, fmt.Errorf("failed to get post-processor for %s: %v", source, err)
-	}
-
 	// If the source has an on-create trigger, run it for each new item
 	// On-create errors are ignored to avoid failing the fetch
-	onCreateArgv, err := GetArgvForAction(db, source, "on_create")
-	if err == nil && len(onCreateArgv) > 0 {
+	if len(onCreateArgv) > 0 {
 		var updatedNewItems []Item
 		for _, item := range newItems {
 			var updatedItem Item
 			var errItem Item
-			updatedItem, state, errItem, err = ExecuteItemAction(item, onCreateArgv, envs, state, DefaultTimeout, postProcess)
+			updatedItem, state, errItem, err = ExecuteItemAction(item, onCreateArgv, envs, state, DefaultTimeout)
 			if err != nil {
 				AddErrorItem(db, errItem)
 				log.Printf("error: on_create failed for %s/%s: %v", item.Source, item.Id, err)
diff --git a/core/source_test.go b/core/source_test.go
index b39c76e..f395f23 100644
--- a/core/source_test.go
+++ b/core/source_test.go
@@ -147,7 +147,7 @@ func TestOnCreateAction(t *testing.T) {
 
 	execute := func(argv []string) []Item {
 		t.Helper()
-		items, _, _, err := Execute("test", argv, nil, nil, "", time.Minute, nil)
+		items, _, _, err := Execute("test", argv, nil, nil, "", time.Minute)
 		if err != nil {
 			t.Fatalf("unexpected error executing test fetch: %v", err)
 		}
@@ -300,7 +300,7 @@ func TestSourceState(t *testing.T) {
 	}
 }
 
-func TestSourceTtx(t *testing.T) {
+func TestSourcePostProcessor(t *testing.T) {
 	db := EphemeralDb(t)
 	if err := AddSource(db, "s"); err != nil {
 		t.Fatal(err)
@@ -323,6 +323,34 @@ func TestSourceTtx(t *testing.T) {
 	}
 }
 
+func TestSourceUpdateAppliesPostProcess(t *testing.T) {
+	db := EphemeralDb(t)
+	if err := AddSource(db, "s"); err != nil {
+		t.Fatal(err)
+	}
+	if err := SetEnvs(db, "s", []string{
+		"INTAKE_TTL=30",
+		"INTAKE_TTD=60",
+		"INTAKE_TTS=90",
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	item := Item{Source: "s", Id: "i"}
+	add, del, err := UpdateWithFetchedItems(db, "s", nil, []Item{item}, time.Now())
+	if add != 1 || del != 0 || err != nil {
+		t.Fatalf("expected 1 add, got %d and err %v", add, err)
+	}
+
+	after, err := GetItem(db, "s", "i")
+	if err != nil {
+		t.Fatalf("item not added: %v", err)
+	}
+	if after.Ttl != 30 || after.Ttd != 60 || after.Tts != 90 {
+		t.Fatalf("Missing value after postProcess: ttl = %d, ttd = %d, tts = %d", after.Ttl, after.Ttd, after.Tts)
+	}
+}
+
 func TestSourceLastUpdated(t *testing.T) {
 	db := EphemeralDb(t)
 	if err := AddSource(db, "s"); err != nil {
diff --git a/web/item.go b/web/item.go
index 4f26136..887eef5 100644
--- a/web/item.go
+++ b/web/item.go
@@ -69,7 +69,7 @@ func (env *Env) doAction(writer http.ResponseWriter, req *http.Request) {
 	id := req.PathValue("id")
 	action := req.PathValue("action")
 
-	state, envs, argv, postProcess, err := core.GetSourceActionInputs(env.db, source, action)
+	state, envs, argv, err := core.GetSourceActionInputs(env.db, source, action)
 	if err != nil {
 		http.Error(writer, fmt.Sprintf("error: failed to load data for %s: %v", source, err), 500)
 	}
@@ -85,7 +85,7 @@ func (env *Env) doAction(writer http.ResponseWriter, req *http.Request) {
 		return
 	}
 
-	newItem, newState, errItem, err := core.ExecuteItemAction(item, argv, envs, state, core.DefaultTimeout, postProcess)
+	newItem, newState, errItem, err := core.ExecuteItemAction(item, argv, envs, state, core.DefaultTimeout)
 	if err != nil {
 		core.AddErrorItem(env.db, errItem)
 		http.Error(writer, err.Error(), 500)
diff --git a/web/source.go b/web/source.go
index 8fbfc00..00c229d 100644
--- a/web/source.go
+++ b/web/source.go
@@ -56,13 +56,13 @@ func (env *Env) fetchSource(writer http.ResponseWriter, req *http.Request) {
 		return
 	}
 
-	state, envs, argv, postProcess, err := core.GetSourceActionInputs(env.db, source, "fetch")
+	state, envs, argv, err := core.GetSourceActionInputs(env.db, source, "fetch")
 	if err != nil {
 		http.Error(writer, fmt.Sprintf("error: failed to get data for %s: %v", source, err.Error()), 500)
 		return
 	}
 
-	items, newState, errItem, err := core.Execute(source, argv, envs, state, "", core.DefaultTimeout, postProcess)
+	items, newState, errItem, err := core.Execute(source, argv, envs, state, "", core.DefaultTimeout)
 	if err != nil {
 		core.AddErrorItem(env.db, errItem)
 		http.Error(writer, fmt.Sprintf("error: failed to execute fetch: %v", err.Error()), 500)