ESP8266EX vs ESP32-WROOM-32E: Which Should You Use?
2026-10-12 · PartVane Electronics
Choosing between the ESP8266EX Wi-Fi SoC and the ESP32-WROOM-32E module is mostly a question of Bluetooth, CPU cores and whether you want a bare chip or a ready module. This comparison uses only the Espressif ESP8266EX and ESP32-WROOM-32E datasheets. Note that one is a chip and the other is a module.
Key differences from the datasheets
| Item | ESP8266EX | ESP32-WROOM-32E |
|---|---|---|
| Form | Wi-Fi SoC, QFN32 (5 mm x 5 mm) | Wi-Fi + Bluetooth module with ESP32 SoC and flash |
| CPU | Tensilica L106 32-bit, up to 160 MHz | Xtensa dual-core 32-bit LX6, up to 240 MHz |
| Wireless | 802.11 b/g/n, 2.4 GHz | Wi-Fi plus Bluetooth V4.2 BR/EDR and Bluetooth LE |
| Memory | On-chip SRAM; user RAM under 50 kB in station mode; no programmable ROM | 520 KB SRAM, 16 KB RTC SRAM |
| Flash | External SPI flash, up to 16 MB supported | 4, 8 or 16 MB Quad SPI on module (by variant) |
| Supply | 2.5 V to 3.6 V | 3.0 V to 3.6 V |
| GPIO | See datasheet pin table | Up to 26 GPIOs |
| Temperature | -40 to 125 C | -40 to 85 C (105 C version also listed) |
When to choose which
- ESP8266EX: Wi-Fi-only designs where you build your own board around the SoC and external flash, or maintain an existing ESP8266 product.
- ESP32-WROOM-32E: new designs needing Bluetooth LE, more RAM, two cores and a pre-certified-style module form factor with flash included.
Check before you buy
The two are not pin or firmware compatible, so moving from one to the other means a new layout and a firmware port. Confirm the exact flash and PSRAM variant (N4, N8, N16, R2) in the datasheet ordering table.
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