ESP32 vs STM32 — Which should I choose?
ESP32 (Espressif) integrates Wi-Fi and Bluetooth into every chip, making it ideal for connected IoT products with fast time-to-market. STM32 (STMicroelectronics) offers superior real-time performance, ultra-low power, and industrial-grade reliability across 1,000+ part numbers. For projects needing wireless connectivity at low cost → ESP32. For precise real-time control, ultra-low power, or industrial/automotive applications → STM32. For professional firmware development on either platform, see our Embedded Systems Development services.
Why This Comparison Matters in 2026
Every IoT product starts with one decision: which microcontroller powers it? ESP32 and STM32 together dominate the 32-bit MCU market for IoT and embedded applications. But they solve fundamentally different problems:
- ESP32 trades determinism for connectivity — every chip has Wi-Fi + Bluetooth built in
- STM32 trades connectivity for control — precise timing, ultra-low power, and a vast peripheral ecosystem
Choosing wrong costs months of redesign. This guide gives you a data-driven framework to choose right the first time.
Architecture Comparison
| Parameter | ESP32-S3 | ESP32-C6 | STM32L4 (Low Power) | STM32H7 (High Perf) | STM32WB55 (Wireless) |
|---|---|---|---|---|---|
| Core | Dual Xtensa LX7 | RISC-V single | Cortex-M4F | Dual Cortex-M7 + M4 | Cortex-M4F + M0+ |
| Clock | 240 MHz | 160 MHz | 80 MHz | 480 MHz | 64 MHz |
| Flash | Up to 16 MB (ext) | Up to 4 MB (ext) | 256 KB–2 MB | 128 KB–2 MB | 1 MB |
| SRAM | 512 KB + 8 MB PSRAM | 512 KB | 64–640 KB | 1 MB | 256 KB |
| Wi-Fi | ✅ 802.11 b/g/n | ✅ Wi-Fi 6 | ❌ | ❌ | ❌ |
| Bluetooth | ✅ BLE 5.0 | ✅ BLE 5.3 | ❌ | ❌ | ✅ BLE 5.4 |
| Thread/Matter | ✅ (C6, H2) | ✅ | ❌ | ❌ | ✅ Zigbee/Thread |
| USB | USB OTG | USB Serial | USB OTG | USB OTG HS | USB |
| CAN | TWAI (1x) | TWAI (1x) | CAN FD (1x) | CAN FD (2x) | ❌ |
| ADC | 12-bit, up to 20ch | 12-bit | 12-bit, up to 24ch | 16-bit, up to 36ch | 12-bit |
| Security | AES, RSA, SHA, flash encryption | AES, RSA, SHA | AES-256, RNG, HASH | AES, HASH, PKA, TrustZone | AES-256, PKA, TrustZone |
Connectivity — The Biggest Differentiator
This is where the choice becomes clear for most projects:
📡 ESP32 — Wireless Native
- ✅ Wi-Fi + BLE on every chip — no external module needed
- ✅ Matter/Thread support (ESP32-C6, ESP32-H2)
- ✅ ESP-NOW for mesh without infrastructure
- ✅ Single-chip BOM for connected products
- ❌ No cellular, no LoRa (external module needed)
🔌 STM32 — Wired + Modular
- ✅ CAN FD, Ethernet, USB HS — industrial protocols built-in
- ✅ STM32WB: BLE 5.4 + Zigbee + Thread
- ✅ STM32WL: LoRa + Sub-GHz built-in
- ✅ Pair with any wireless module — total flexibility
- ❌ Most SKUs require external wireless chip
Bottom line: If your product needs Wi-Fi → ESP32 saves you an external module, antenna matching network, and 6+ weeks of RF certification effort. If your product needs CAN bus, Ethernet, or LoRa → STM32 has purpose-built silicon.
Power Consumption — Deep Dive
Power consumption is often the deciding factor for battery-powered products:
| Mode | ESP32-S3 | STM32L476 | STM32WB55 | Winner |
|---|---|---|---|---|
| Active (CPU only) | ~40 mA @ 240 MHz | ~5 mA @ 80 MHz | ~4 mA @ 64 MHz | STM32 (8x lower) |
| Active (Wi-Fi TX) | ~240 mA | N/A | N/A | — |
| Active (BLE TX) | ~130 mA | N/A | ~6 mA | STM32WB (20x lower) |
| Light sleep | ~600 µA | ~1.2 µA (Stop 1) | ~2 µA (Stop 1) | STM32 (300x lower) |
| Deep sleep | ~7 µA | ~0.3 µA (Standby) | ~0.6 µA (Standby) | STM32 (10x lower) |
| Shutdown | ~1 µA | ~0.02 µA (VBAT) | ~0.05 µA (VBAT) | STM32 (50x lower) |
⚡ What this means in practice
A soil moisture sensor transmitting once per hour via BLE on STM32WB can run 5+ years on a CR2032. The same sensor on ESP32 with Wi-Fi might last 2–3 weeks. But if you need Wi-Fi connectivity, ESP32 wins because STM32 would need an external Wi-Fi module consuming similar power.
Pricing & BOM Impact (2026)
| Factor | ESP32 | STM32 | Notes |
|---|---|---|---|
| Chip cost (1K qty) | $1.50–$3.50 | $1.80–$15.00 | ESP32 range is tighter; STM32 spans entry to high-perf |
| Module cost | $2.50–$5.00 | $5.00–$15.00 | ESP32 modules include antenna; STM32 wireless modules are pricier |
| Dev board | $5–$15 | $12–$50 | ESP32 dev boards are significantly cheaper |
| External Wi-Fi module | Included | $3–$8 | STM32 needs external module for Wi-Fi |
| External BLE module | Included | $2–$5 (or use STM32WB) | STM32WB includes BLE |
| Total BOM (simple IoT) | $4–$8 | $8–$20 | ESP32 wins on connected products |
| Total BOM (industrial) | $5–$12 | $3–$8 | STM32 wins when no wireless needed |
Development Ecosystem
| Aspect | ESP32 (ESP-IDF) | STM32 (STM32Cube) |
|---|---|---|
| Official IDE | VS Code + ESP-IDF Extension | STM32CubeIDE (Eclipse-based) |
| Config tool | menuconfig (Kconfig) | STM32CubeMX (visual pin/clock config) |
| RTOS | FreeRTOS (default in ESP-IDF) | FreeRTOS, Azure RTOS, bare-metal |
| Zephyr support | ✅ Growing (ESP32-C6, H2) | ✅ Excellent (primary target) |
| Arduino support | ✅ Excellent | ✅ via STM32duino |
| MicroPython | ✅ Official port | ✅ Community port |
| Documentation | Good (English) | Excellent (datasheets, app notes, reference manuals) |
| Community | Large maker/IoT community | Large professional/industrial community |
| Debug | JTAG (limited trace) | SWD/JTAG, ETM trace, CoreSight |
| Static analysis | Basic | Full MISRA C, Coverity, PC-lint support |
| Longevity guarantee | 3–5 years typical | 10+ years (industrial commitment) |
When to Choose ESP32
✅ ESP32 is the right choice when:
- Your product needs Wi-Fi — No other MCU family integrates Wi-Fi as cost-effectively
- You're building a Matter/Thread device — ESP32-C6 and H2 have native support
- Budget is tight — $2.50 for a complete wireless module is hard to beat
- Fast prototyping matters — Arduino/MicroPython support means working prototypes in hours
- Smart home / consumer IoT — Light bulbs, plugs, sensors, displays
- Edge AI on budget — ESP32-S3 has vector instructions for neural network acceleration
Typical ESP32 products: Smart home devices, Wi-Fi gateways, interactive displays, voice assistants, consumer IoT sensors, ESP-NOW mesh networks.
When to Choose STM32
✅ STM32 is the right choice when:
- Ultra-low power is critical — 300 nA standby means years on a coin cell
- Real-time determinism matters — Motor control, PID loops, safety-critical timing
- Industrial protocols needed — CAN FD, industrial Ethernet, Modbus, HART
- Long product lifecycle — 10+ year availability guarantee for medical/auto/industrial
- Safety certification required — ISO 26262, IEC 61508, IEC 62304 tooling available
- Advanced security — TrustZone, SESIP3, PSA Level 3 certified variants
Typical STM32 products: Motor drives, industrial PLCs, medical devices, automotive ECUs, battery management systems, precision instruments, LoRa sensor nodes (STM32WL).
The Hybrid Approach — Use Both
In complex products, the best architecture often combines both platforms:
🔗 ESP32 + STM32 in one product
- STM32 handles real-time control (motor, sensors, safety loops)
- ESP32 handles connectivity (Wi-Fi, cloud API, OTA updates, UI)
- Communication via SPI or UART between the two
This is the architecture used in many industrial IoT gateways, smart appliances, and EV chargers — deterministic control + cloud connectivity without compromising either.
What About Nordic nRF?
If your product needs BLE without Wi-Fi, consider a third option:
| Feature | ESP32 | STM32WB55 | Nordic nRF5340 |
|---|---|---|---|
| BLE performance | Good | Very good | Best-in-class |
| BLE 5.4 features | Partial | ✅ Full | ✅ Full |
| Thread/Matter | ✅ (C6/H2 only) | ✅ | ✅ |
| Direction Finding | ❌ | ❌ | ✅ AoA/AoD |
| BLE power | ~130 mA TX | ~6 mA TX | ~4 mA TX |
| SDK | ESP-IDF | STM32Cube | nRF Connect SDK (Zephyr) |
| Best for | Wi-Fi + BLE combo | BLE + Zigbee industrial | Pure BLE, audio, wearables |
For BLE-first products, Nordic nRF is often the best choice. We develop on all three platforms — see our Embedded Systems Development capabilities.
Decision Framework
Use this flowchart-style guide to make your choice:
| Your Priority | → Choose | Specific Part |
|---|---|---|
| Wi-Fi connectivity | ESP32-S3 or ESP32-C6 | C6 for Wi-Fi 6 + Thread |
| Ultra-low power (no wireless) | STM32L4/U5 | L476 for general, U5 for ultra-low |
| BLE + Thread (no Wi-Fi) | Nordic nRF5340 or STM32WB | nRF for best BLE, WB for Zigbee |
| LoRaWAN | STM32WL | Integrated Sub-GHz radio |
| Motor control / real-time | STM32G4 or STM32H7 | G4 for motor, H7 for DSP |
| Industrial CAN + Ethernet | STM32H5 or STM32F4 | H5 for TrustZone + industrial |
| Budget consumer IoT | ESP32-C3 | Cheapest Wi-Fi + BLE option |
| Safety-critical | STM32 (any certified) | With IEC 61508 / ISO 26262 |
| Wi-Fi + real-time hybrid | ESP32 + STM32 | Dual-chip architecture |
EU Compliance Considerations
Both platforms must meet EU Cyber Resilience Act requirements for products sold in the EU:
| CRA Requirement | ESP32 | STM32 |
|---|---|---|
| Secure boot | ✅ RSA-based flash encryption | ✅ Secure boot + TrustZone |
| OTA updates | ✅ Built-in OTA partition scheme | ✅ Via MCUboot or STM32 SBSFU |
| Vulnerability management | ⚠️ Community-driven CVE process | ✅ Formal PSA/SESIP certification |
| SBOM generation | ⚠️ Manual | ✅ Toolchain support |
For CRA-compliant firmware on either platform, see our EU Compliance services.
Our Recommendation
There is no universally “better” MCU — only the right MCU for your specific product:
📡
Connected IoT
→ ESP32
⚙️
Industrial / Safety
→ STM32
🔗
Complex Products
→ Both
Need help choosing or developing firmware?
We develop production firmware on ESP32, STM32, and Nordic nRF platforms — from platform selection through CRA-compliant deployment. Whether you're starting from scratch or need firmware for existing hardware, our team delivers production-ready embedded solutions.
Start Your Project →Related Resources
- Embedded Systems Development — Our ESP32, STM32, and Nordic development services
- RTOS — Choosing between FreeRTOS, Zephyr, and bare-metal
- BLE — Bluetooth Low Energy protocol deep dive
- MCUboot — Secure bootloader for STM32 and ESP32
- EU Compliance — CRA requirements for connected products
- FPGA vs ASIC — When MCUs aren’t enough — custom digital logic