| Hardware and OS | Vivo X21s | |
| Operating system | Funtouch 4.5 OS (Android 8.1 Oreo) | |
| Processor | 4x 2.2 GHz Kryo 260, 4x 1.84 GHz Kryo 260, Cores: 8 | |
| GPU | Qualcomm Adreno 512 | |
| RAM | 6 GB, 1866 MHz | |
| Internal Storage | 128 GB | |
| Memory Card Slot | microSD, microSDHC, microSDXC | |
| User Interface | Yes | |
| Display | Vivo X21s | other phones |
| Type | Super AMOLED | |
| Size | 6.41 inches | |
| Resolution | 1080 x 2340 pixels | |
| Colors | 16M | |
| Pixel Density | 402 ppi | |
| Touchscreen | Yes | |
| Protection | Corning Gorilla Glass 3 | |
| Features | Capacitive, Multi-touch, Scratch resistant | |
| Connectivity | Vivo X21s | other phones |
| 4G Network | Yes | |
| Wi-Fi | a, b, g, n, n 5GHz, ac, Dual band, Wi-Fi Hotspot, Wi-Fi Direct | |
| GPS | GPS, A-GPS, GLONASS, BeiDou | |
| NFC | No | |
| USB | 2.0, Micro USB | |
| Speed | LTE 850 MHz LTE 900 MHz LTE 1700/2100 MHz LTE 1800 MHz LTE 1900 MHz LTE 2100 MHz LTE 2600 MHz LTE-TDD 1900 MHz (B39) LTE-TDD 2300 MHz (B40) LTE-TDD 2500 MHz (B41) LTE-TDD 2600 MHz (B38) | |
| SIM | Nano SIM | |
| Dual SIM | Nano-SIM, Nano-SIM / microSD | |
| Wireless Charging | No | |
| Camera | Vivo X21s | other phones |
| Main camera | 12.19 MP (megapixels) | |
| Features | LED | |
| Image | 4032 x 3024 pixels | |
| Selfie camera | 24.84 MP (megapixels) | |
| Multimedia | Vivo X21s | other phones |
| Loudspeaker | Yes | |
| Handsfree | Yes | |
| Radio | Yes | |
| Video Out | Yes | |
| Ring Tones | Yes | |
| 3.5 mm Jack | yes | |
| Design | Vivo X21s | other phones |
| Dimensions | 75.08 x 157.9 x 7.9 mm | |
| Waterproof | No | |
| Weight | 156 g | |
| Battery | Vivo X21s | other phones |
| Capacity | 3330 mAh, Li-Polymer | |
| Other | Vivo X21s | other phones |
| Sensors | Proximity, Light, Accelerometer, Compass, Gyroscope, Fingerprint | |
