diff --git a/src/appendix/cheat-sheet.md b/src/appendix/cheat-sheet.md
index aebb27c..e6835bb 100644
--- a/src/appendix/cheat-sheet.md
+++ b/src/appendix/cheat-sheet.md
@@ -249,7 +249,7 @@ CS = kura_changeset:cast(SchemaModule, ExistingData, Params, AllowedFields).
 
 %% Validations
 kura_changeset:validate_required(CS, [field1, field2])
-kura_changeset:validate_format(CS, field, "regex")
+kura_changeset:validate_format(CS, field, <<"regex">>)
 kura_changeset:validate_length(CS, field, [{min, 3}, {max, 200}])
 kura_changeset:validate_number(CS, field, [{greater_than, 0}])
 kura_changeset:validate_inclusion(CS, field, [val1, val2, val3])
diff --git a/src/building-api/advanced-data.md b/src/building-api/advanced-data.md
index c83f6f1..cab44fd 100644
--- a/src/building-api/advanced-data.md
+++ b/src/building-api/advanced-data.md
@@ -265,7 +265,7 @@ index(_Req) ->
     {ok, Tags} = blog_repo:all(Q1),
     {json, #{tags => Tags}}.
 
-create(#{params := Params}) ->
+create(#{json := Params}) ->
     CS = tag:changeset(#{}, Params),
     case blog_repo:insert(CS) of
         {ok, Tag} ->
diff --git a/src/data-layer/changesets.md b/src/data-layer/changesets.md
index f10f60f..5d94894 100644
--- a/src/data-layer/changesets.md
+++ b/src/data-layer/changesets.md
@@ -82,7 +82,7 @@ fields() ->
 changeset(Data, Params) ->
     CS = kura_changeset:cast(user, Data, Params, [username, email, password_hash]),
     CS1 = kura_changeset:validate_required(CS, [username, email, password_hash]),
-    CS2 = kura_changeset:validate_format(CS1, email, "^[^@]+@[^@]+\\.[^@]+$"),
+    CS2 = kura_changeset:validate_format(CS1, email, <<"^[^@]+@[^@]+\\.[^@]+$">>),
     CS3 = kura_changeset:validate_length(CS2, username, [{min, 2}, {max, 50}]),
     CS4 = kura_changeset:unique_constraint(CS3, email),
     kura_changeset:unique_constraint(CS4, username).
@@ -130,7 +130,7 @@ changeset_errors_to_json(#kura_changeset{errors = Errors}) ->
 Use it in controllers:
 
 ```erlang
-create(#{params := Params}) ->
+create(#{json := Params}) ->
     CS = post:changeset(#{}, Params),
     case blog_repo:insert(CS) of
         {ok, Post} ->
diff --git a/src/production/pubsub.md b/src/production/pubsub.md
index 89b57b6..33982b5 100644
--- a/src/production/pubsub.md
+++ b/src/production/pubsub.md
@@ -82,7 +82,7 @@ On connect, the handler joins both the `posts` and `comments` channels. Any pub/
 Update the posts controller to broadcast on changes:
 
 ```erlang
-create(#{params := Params}) ->
+create(#{json := Params}) ->
     CS = post:changeset(#{}, Params),
     case blog_repo:insert(CS) of
         {ok, Post} ->
diff --git a/src/testing-errors/testing.md b/src/testing-errors/testing.md
index 0373d1b..3722fc7 100644
--- a/src/testing-errors/testing.md
+++ b/src/testing-errors/testing.md
@@ -136,15 +136,15 @@ Test your security functions directly:
 
 valid_login_test() ->
     Req = nova_test_req:new(post, "/login"),
-    Req1 = nova_test_req:with_json(#{<<"username">> => <<"admin">>,
-                                     <<"password">> => <<"password">>}, Req),
+    Req1 = Req#{params => #{<<"username">> => <<"admin">>,
+                             <<"password">> => <<"password">>}},
     ?assertMatch({true, #{authed := true, username := <<"admin">>}},
                  blog_auth:username_password(Req1)).
 
 invalid_password_test() ->
     Req = nova_test_req:new(post, "/login"),
-    Req1 = nova_test_req:with_json(#{<<"username">> => <<"admin">>,
-                                     <<"password">> => <<"wrong">>}, Req),
+    Req1 = Req#{params => #{<<"username">> => <<"admin">>,
+                             <<"password">> => <<"wrong">>}},
     ?assertEqual(false, blog_auth:username_password(Req1)).
 
 missing_params_test() ->