Dio REST call response is slow than Postman

[devsideal]

Package

dio

Version

5.3.2

Operating-System

Android, iOS

Output of flutter doctor -v

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 3.13.0, on Ubuntu 22.04.3 LTS 6.5.0-14-generic, locale en_IN)
[✓] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
[✓] Chrome - develop for the web
[✗] Linux toolchain - develop for Linux desktop
    ✗ clang++ is required for Linux development.
      It is likely available from your distribution (e.g.: apt install clang), or can be downloaded from https://releases.llvm.org/
    ✗ CMake is required for Linux development.
      It is likely available from your distribution (e.g.: apt install cmake), or can be downloaded from https://cmake.org/download/
    ✗ ninja is required for Linux development.
      It is likely available from your distribution (e.g.: apt install ninja-build), or can be downloaded from https://github.com/ninja-build/ninja/releases
    ✗ pkg-config is required for Linux development.
      It is likely available from your distribution (e.g.: apt install pkg-config), or can be downloaded from https://www.freedesktop.org/wiki/Software/pkg-config/
[✓] Android Studio (version 2023.1)
[✓] VS Code (version unknown)
    ✗ Unable to determine VS Code version.
[✓] Connected device (3 available)
[✓] Network resources

Dart Version

3.1.0

Steps to Reproduce

• Just send a simple Get request and calculate response time
• Do the same thing with Postman and see the response time is much lesser than Dio.

I experimented with various APIs, and the outcomes were consistently similar, with Dio resulting in approximately three times longer response times, See the differences below:

Expected Result

Do Rest call response time should correct time that can be measure with postman

Actual Result

Geetting Api response time approx 3x longer than Postman

[AlexV525]

Please try HttpClient.

[devsideal]

@AlexV525 Looks simmilar with HttpClient too

[AlexV525]

Thanks for the verification. There is nothing Dio can do here, which is likely an underlying platform issue.

[devsideal]

Thanks @AlexV525 for the confirmation, FYI, I posted the same for flutter community as well.

[kuhnroyal]

You can try to use the native_dio_adapter which uses the cronet client on Android via FFI. That might be more performant.

[Tienisto]

This is mostly an issue with the slow TLS implementation in Dart: dart-lang/sdk#54752
Sadly, your issue in the Flutter repo got closed due to being "invalid" flutter/flutter#142042
I have created rhttp if the performance is critical for your app.