diff --git a/lib/sentry/transport.ex b/lib/sentry/transport.ex
index f7f10440..36ae4fb0 100644
--- a/lib/sentry/transport.ex
+++ b/lib/sentry/transport.ex
@@ -136,7 +136,7 @@ defmodule Sentry.Transport do
   end
 
   defp update_rate_limits(headers, status) do
-    rate_limits_header = :proplists.get_value("X-Sentry-Rate-Limits", headers, nil)
+    rate_limits_header = get_header(headers, "x-sentry-rate-limits")
 
     cond do
       is_binary(rate_limits_header) ->
@@ -154,7 +154,7 @@ defmodule Sentry.Transport do
   end
 
   defp get_global_delay(headers) do
-    with timeout when is_binary(timeout) <- :proplists.get_value("Retry-After", headers, nil),
+    with timeout when is_binary(timeout) <- get_header(headers, "retry-after"),
          {delay, ""} <- Integer.parse(timeout) do
       delay
     else
@@ -164,6 +164,16 @@ defmodule Sentry.Transport do
     end
   end
 
+  defp get_header(headers, lowercase_name) do
+    Enum.find_value(headers, fn
+      {header_name, value} when is_binary(header_name) ->
+        if String.downcase(header_name) == lowercase_name, do: value
+
+      _other ->
+        nil
+    end)
+  end
+
   defp get_endpoint_and_headers do
     %Sentry.DSN{} = dsn = Config.dsn()
 
diff --git a/test/sentry/telemetry_processor_integration_test.exs b/test/sentry/telemetry_processor_integration_test.exs
index 6cab2394..61be3b53 100644
--- a/test/sentry/telemetry_processor_integration_test.exs
+++ b/test/sentry/telemetry_processor_integration_test.exs
@@ -311,9 +311,7 @@ defmodule Sentry.TelemetryProcessorIntegrationTest do
       ref = make_ref()
       request_count = :counters.new(1, [])
 
-      # Use HackneyClient because FinchClient (Mint) lowercases response headers,
-      # which prevents the transport from matching "X-Sentry-Rate-Limits".
-      put_test_config(client: Sentry.HackneyClient)
+      put_test_config(client: Sentry.FinchClient)
 
       Bypass.expect(ctx.bypass, "POST", "/api/1/envelope/", fn conn ->
         count = :counters.get(request_count, 1)
diff --git a/test/sentry_test.exs b/test/sentry_test.exs
index 964ad8bf..7ea4ea43 100644
--- a/test/sentry_test.exs
+++ b/test/sentry_test.exs
@@ -135,6 +135,32 @@ defmodule SentryTest do
     assert :ignored = Sentry.send_event(event)
   end
 
+  test "reads Retry-After response headers case-insensitively", %{bypass: bypass} do
+    request_count = :counters.new(1, [])
+    put_test_config(client: Sentry.FinchClient)
+
+    Bypass.expect(bypass, "POST", "/api/1/envelope/", fn conn ->
+      request_number = :counters.get(request_count, 1)
+      :counters.add(request_count, 1, 1)
+
+      if request_number == 0 do
+        conn
+        |> Plug.Conn.put_resp_header("Retry-After", "0")
+        |> Plug.Conn.resp(429, ~s<{}>)
+      else
+        Plug.Conn.resp(conn, 200, ~s<{"id": "#{Sentry.UUID.uuid4_hex()}"}>)
+      end
+    end)
+
+    assert {:error, %Sentry.ClientError{reason: :rate_limited}} =
+             Sentry.capture_message("rate-limited", result: :sync, request_retries: [])
+
+    assert {:ok, _event_id} =
+             Sentry.capture_message("accepted", result: :sync, request_retries: [])
+
+    assert :counters.get(request_count, 1) == 2
+  end
+
   describe "send_check_in/1" do
     test "posts a check-in with all the explicit arguments", %{bypass: bypass} do
       put_test_config(environment_name: "test", release: "1.3.2")
@@ -248,6 +274,47 @@ defmodule SentryTest do
       assert_sentry_report(:transaction, transaction: "test-transaction")
     end
 
+    test "does not apply categorized error rate limits to transactions", %{
+      bypass: bypass,
+      transaction: transaction
+    } do
+      test_pid = self()
+      ref = make_ref()
+      request_count = :counters.new(1, [])
+      put_test_config(client: Sentry.FinchClient)
+
+      Bypass.expect(bypass, "POST", "/api/1/envelope/", fn conn ->
+        request_number = :counters.get(request_count, 1)
+        :counters.add(request_count, 1, 1)
+
+        if request_number == 0 do
+          conn
+          |> Plug.Conn.put_resp_header("X-Sentry-Rate-Limits", "60:error:organization")
+          |> Plug.Conn.resp(429, ~s<{"error": "Rate limited"}>)
+        else
+          {:ok, body, conn} = Plug.Conn.read_body(conn)
+
+          if body =~ ~s("type":"transaction") do
+            send(test_pid, {:bypass_envelope, ref, body})
+          end
+
+          Plug.Conn.resp(conn, 200, ~s<{"id": "#{Sentry.UUID.uuid4_hex()}"}>)
+        end
+      end)
+
+      assert {:error, %Sentry.ClientError{reason: :rate_limited}} =
+               Sentry.capture_message(
+                 "rate-limited-error",
+                 result: :sync,
+                 request_retries: []
+               )
+
+      assert {:ok, _event_id} =
+               Sentry.send_transaction(transaction, result: :sync, request_retries: [])
+
+      assert_sentry_transaction(ref, transaction: "test-transaction")
+    end
+
     test "validates options", %{transaction: transaction} do
       assert_raise NimbleOptions.ValidationError, fn ->
         Sentry.send_transaction(transaction, client: "oops")