With Silicon Labs Bluetooth Low Energy SDK, you can build smooth, reliable, and secure wireless connectivity for your IoT applications. The SDK has your entire product life-cycle covered, from development to over-the-air maintenance. The Silicon Labs simplified stack always contains the latest protocol version, cutting-edge features, and robust security. It works with C-based GCC or IAR compilers and Silicon Labs Simplicity Studio, our intuitive development environment with the most valuable dev toolbox free-of-charge – including an Energy Profiler, Network Analyzer, Pin Tool, visual GATT configurator, and more.
Overview
Bluetooth Low Energy SDK
The Bluetooth Low Energy Software Development Kit is part of the Silicon Labs Simplicity SDK. It consists of an extensive library of example projects, peripheral drivers, the Bluetooth Low Energy protocol stack, and the API.
Hardware-agnostic Bluetooth Stack
With Silicon Labs, you have just one proven, hardware-agnostic software stack and API for Bluetooth Low Energy. The single-stack approach speeds up development and radically minimizes Bluetooth SW and HW migration efforts to your new products – it results in a more consistent code and reduces software development and maintenance costs.
Bluetooth Low Energy
Keep your products ahead of the competition! Silicon Labs Bluetooth Low Energy stack is in the frontline to support the latest specifications and it delivers all the essential features among the first in the world.
Bluetooth Low Energy Software Features and Benefits
Add the most valuable Bluetooth Low Energy features to your IoT applications. Here’s a rundown of all the crucial features on the Silicon Labs stack.
| Features | Benefits | |
|---|---|---|
| Multiprotocol Support on a Single-chip | Dynamic multiprotocol allows you to run Bluetooth, Thread, Zigbee, and Proprietary protocols reliably on one radio, by time-slicing radio operations seamlessly between multiple stacks. | |
| Direction Finding | Silicon Labs Bluetooth Direction Finding is based on the angle of arrival (AoA) and angle of departure (AoD) techniques. It enables high-accuracy positioning of below one meter (<1 m) for your asset tracking and indoor positioning applications – 3-5 times higher accuracy than RSSI. | |
| Apple HomeKit | Develop accessories for the Apple HomeKit ecosystem faster and with lower interoperability risks by building upon the full Apple HomeKit support on our BLE stack – it is available via the Apple MFI license on a wide range of SoCs and modules. | |
| Wi-Fi Coexistence | Are you developing IoT devices with multiple 2.4 GHz protocols such as Wi-Fi and Bluetooth? With Silicon Labs’ Wi-Fi Coexistence, you can reduce interference and increase reliability! It is based on packet traffic arbitration (PTA) and allows the Bluetooth device to coordinate transmitting and receiving with the collocated Wi-Fi device. | |
| Long Range | LE Coded PHY (500kbps and 125kbps) enables your Bluetooth devices with up to two times (2X) longer range compared to the 1M PHY modulation – which can correspond to several hundreds of meters. LE Coded PHY improves sensitivity by 4-6 dB, which reduces retransmissions, and increases battery life and connectivity reliability. (SoCs and modules for Long Range: B/MG13, B/MG21, and B/MG22) | |
| High Data Throughput | Our Bluetooth provides the 2M PHY modulation for your high-data throughput IoT applications to unleash a throughput of 1300 kbps on selected SoCs and modules. The 1M PHY delivers a throughput of 700 kbps. (SoCs and modules for 2M PHY: B/MG12, B/MG13, B/MG21, and B/MG22) | |
| Up to 32 Simultaneous Connections | Silicon Labs Bluetooth and Series 2 hardware support 32 simultaneous connections – the high number of connections allows you to connect more nodes per device or base station and reduce the costs of large IoT solutions. Series 1 hardware supports up to 13 simultaneous connections. | |
| Extended Advertisements | The Bluetooth Advertisement Extensions offload the three advertisement channels to allow more capacity for beacons, way-finding, indoor navigation, and asset tracking. The three advertisement channels now only carry pointers to the advertisements, which are transmitted on the 37 data channels. The extended advertisement packet size of up to 1650 bytes is supported, allowing you to fit in more payload. | |
| GATT | Silicon Labs supports all GATT-based Bluetooth profiles and services, including the GATT caching. | |
| GATT Caching | GATT Caching enables your Bluetooth applications a faster client reconnection time and lowers power consumption. It avoids energy-intensive GATT database discovery of a remote device during each connection setup by storing a local copy for future use. | |
| Pairing Processes | Silicon Labs Bluetooth provides you with all the specified pairing processes, including Just Works and Man-in-the-Middle with numeric comparison and Out-of-Band passkey. | |
| Packet Sizes | Higher link layer packet size of up to 251 bytes and ATT protocol packet size of up to 250 bytes allow you to increase data throughput and reduce power consumption (larger packets reduce overhead). | |
| Host Interfaces | Host Network Co-processor (NCP) interfaces include 4-wire UART with RTS/CTS control or 2-wire UART without RTS/CTS GPIOs for sleep and wakeup management. | |
| Memory Options | You can adjust the memory block size for your data and settings. Silicon Labs Bluetooth provides two non-volatile memory options: NVM3 and Persistent Storage (PS) are supported with B/MG1, B/MG12, B/MG13, while NVM3 is supported with B/MG21 and B/MG22. | |
| Flexible Device Roles | No need to hardcode device roles – Silicon Labs Bluetooth runtime supports interchangeable and concurrent roles with the central, peripheral, broadcaster, and observer roles. | |
| Other Features | LE secure connections, LE Privacy 1.2 (peripheral), LE packet length extensions, Whitelisting (central side), LE Power Control, LE Data Length Extensions and LE Dual-topology |
Security
Bluetooth Stack Security Features
Your most common threats in wireless communications are passive eavesdropping, Man-In-The-Middle (MITM), and privacy tracking. With Silicon Labs you get all the Bluetooth standard security features to protect your customers’ privacy:
Pairing — Trusted relationships between devices via secure keys
Bonding — Stores the keys created during pairing for later connections
Device Authentication — Verifies that devices have the same keys to protect from MITM
Encryption — Ensures data confidentiality based on the AES-128 algorithm
Data signing — Protects against data alteration
Secure Execution Environment
If your IoT application requires security beyond the Bluetooth specification, Silicon Labs hardware supports mbed TLS, a trusted execution environment for Bluetooth applications.
Secure Maintenance Over-the-Air
Maintain your entire installed base via the secure OTA firmware update, which authenticates the update file source, encrypts the process using AES-128, and guarantees an unaltered firmware via the secure boot.
Secure Firmware Updates
Our Secure Gecko Bootloader supports authenticated and AES-128 encrypted software updates via OTA, UART, Secure Boot, flash partitioning, and internal and external SPI for flash.
Hardware Security
In addition to the full range of software security features, your IoT applications will be protected by Silicon Labs hardware security.
BLE Development Tools
Silicon Labs Bluetooth Low Energy SDK uses C programming language, and you can use it with GCC or IAR compilers. For ultimate speed and easiness of development, we recommend our Simplicity Studio, the unified development environment for all Silicon Labs technologies and hardware.
Simplicity Studio
Simplicity Studio provides an intuitive dev experience and the most valuable toolbox free-of-charge.
When you install Simplicity Studio, it automatically customizes your development environment and installs the SDKs based on the target hardware. Everything is wrapped into a single, intuitive, end-to-end dev experience – including Eclipse-based IDE, the correct version of GCC toolchain, Make, Commander, J-Link drivers, energy profiler, network analyzer, PIN tool, GATT configurator, Mesh Configurator, and more. It is the only development tool to download with Silicon Labs.
Downloads
Download and Install Simplicity Studio
Get up and running quickly with Bluetooth Low Energy SDKs, precompiled demos, application notes and examples. Use advanced tools including energy profiling and network analysis to optimize your wireless systems. Choose your software package below.
GitHub
Silicon Labs wireless IoT SDKs and code examples are also available for download on GitHub.
VS Code IDE Support
In addition to the Simplicity Studio IDE, we also support VS Code that can be used in companion with all of our unique development tools.
Download Mobile Apps
Simplicity Connect
The only BLE mobile app with data throughput and smartphone interoperability testing – and much more.
Tech Docs
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Simplicity SDK
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Gecko SDK
Simplicity SDK Release Notes (2024.12.0)
Latest Release - Q2/2025 (April 2025)
Bluetooth LE Version 9.1.0.0
- Bluetooth
- GA release of Periodic Advertisement BGAPI event
- BT LE Connection Subrating
- Accept List Based Auto-connect
- BT Atlanta (v6.0) LL and Host Qualification
- Channel Sounding sparse channel map support
- Channel Sounding antenna switching support
- CBAP - CPMS integration
- Multiprotocol
- ZigbeeD and OTBR support on OpenWRT – GA
- DMP BLE + CMP ZB & Matter/OT with Concurrent Listening on MG26 for SoC – GA
- 802.15.4 Unified radio scheduler priority component
- Debian packaging support for MP host applications - Alpha
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/04 | Version 9.1.0.0  |
| 2025/02 | Version 9.0.1.0 |
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| 2024 | 2024/12 | Version 9.0.0.0 |
| 2024/09 | Version 8.2.0.0 |
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| 2024/07 | Version 8.1.0.0 |
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| 2024/06 | Version 8.0.0.0 |
Bluetooth Location Services Version 9.1.0.0
- Channel Sounding sparse channel map support
- Channel Sounding antenna switching support
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/04 | Version 9.1.0.0 |
| 2024 | 2024/12 | Version 9.0.0.0 |
| 2024/09 | Version 8.2.0.0 |
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| 2024/07 | Version 8.1.0.0 |
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| 2024/06 | Version 8.0.0.0 |
Gecko SDK Release Notes (4.4.6.0)
Latest Release - Q1/2025 (February 2025)
Bluetooth Version 7.3.0.0
- Bluetooth
- New feature component bluetooth_feature_connection_analyzer provides the functionality to capture and analyze the RSSI of transmissions on a Bluetooth connection
- New feature component bluetooth_feature_connection_analyzer provides the functionality to capture and analyze the RSSI of transmissions on a Bluetooth connection
- Multiprotocol
- Concurrent Listening support (RCP) – MG21 and MG24
- Concurrent Multiprotocol (CMP) Zigbee NCP + OpenThread RCP – production quality
- Dynamic Multiprotocol Bluetooth + Concurrent Multiprotocol (CMP) Zigbee and OpenThread support on SoC
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/02 | Version 7.3.0.0 |
| 2025/01 | Version 5.2.0.0 |
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| 2024 | 2024/10 | Version 7.2.0.0 |
| 2024/08 | Version 7.1.2.0 |
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| 2024/07 | Version 5.1.4.1 |
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| 2024/05 | Version 7.1.1.0 |
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| 2024/04 | Version 7.1.0.0 |
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| 2024/03 | Version 6.3.0.0 |
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| 2024/02 | Version 7.0.1.0 |
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| 2024/01 | Version 5.1.4.0 |
Bluetooth Location Services Version 7.3.0.0
- Underlying platform changes only
| Release | Date | Release Notes |
|---|---|---|
| 2025 | 2025/02 | Version 7.3.0.0 |
| 2025/01 | Version 5.2.0.0 |
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| 2024 | 2024/10 | Version 7.2.0.0 |
| 2024/08 | Version 7.1.2.0 |
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| 2024/07 | Version 5.1.4.1 |
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| 2024/05 | Version 7.1.1.0 |
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| 2024/04 | Version 7.1.0.0 |
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| 2024/03 | Version 6.3.0.0 |
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| 2024/02 | Version 7.0.1.0 |
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| 2024/01 | Version 5.1.4.0 |
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