CycloneTCP Licensing Options

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Our Open Source software are licensed under GPL version 2. This is ideal for evaluating either our software, for private use, or for integrating exclusively with other GPL software. If you intend to distribute your software and link our software with your application, the GPL requires you to provide public and full access to all source code on a nondiscriminatory basis. If you do not wish to provide source code of your application, you must purchase a commercial license. If you are evaluating either of our products internally, and not distributing any products containing our source code, then you may be able to use the GPL license for this evaluation. Once complete, you may purchase a commercial license so that you can distribute your product. You may evaluate, develop, modify, and embed our software in your application or product provided it is not distributed. You may copy and modify the source code provided all copies fall under the GPL license.
If the GPL license cannot be considered for evaluating our software (because your project links to non GPL-compatible third party software), then you may consider our evaluation license (Eval). The software is provided in source form for a short-term evaluation only. The evaluation license expires 90 days after the date you first download the software. You may use the software only for the sole purpose of internal testing and evaluation to determine whether you want license the software on a commercial basis. If you plan to use the software in a commercial product, you are required to purchase a commercial license. After the 90-day evaluation period, you agree to either purchase a commercial license or delete all copies of the software. If you wish to extend the evaluation period, you must contact us.
Our software is also available under a commercial license (Lite, Pro or Ultimate) for proprietary developments in a commercial context. This commercial license provides you with the following benefits:

  • The right to develop and modify the software to embed it in your products.
  • The ability to redistribute your products with the firmware.
  • The ability to keep your source code private.
  • Simple royalty-free license (one-time license fee).
  • Software maintenance for updates, upgrades and security patches.
  • Priority access to support.

Our Commercial Licenses

CycloneTCP Lite

CycloneTCP Lite includes all the core features of the IPv4 stack but does not provide any application protocols. This version targets developers who only need access to sockets and basic protocols (DHCP, DNS and TFTP).

CycloneTCP Pro

CycloneTCP Pro is a full-featured IPv4 stack that comes with a full set of application protocols such as FTP, HTTP, MQTT, MQTT-SN, CoAP, SMTP, SNMPv1/v2c/v3, SNTP, TFTP and Modbus/TCP.

CycloneTCP Ultimate

CycloneTCP Ultimate is a full-featured dual stack (IPv4 and/or IPv6). This version includes application protocols such as FTP, HTTP, MQTT, MQTT-SN, CoAP, SMTP, SNMPv1/v2c/v3, SNTP, TFTP and Modbus/TCP.

Edition CycloneTCP
Lite, Pro, Ultimate
License Open Source
(90 days)
Commercial Products
(Non-GPLv2 Version)
Source Code
Doxygen Documentation
Royalty Free
IP Infringement Protection
PDF User's Manual Optional
Technical Support Optional
IP fragmentation and reassembly

CycloneTCP Feature Comparison

IP fragmentation and reassembly
BSD Sockets
DHCP Client
DNS Client
NetBIOS Responder
VLAN (802.1q)
TFTP Client and Server
DHCP Server
FTP Client and Server
HTTP server
MQTT client
MQTT-SN client
CoAP Client
SMTP Client
SNTP Client
SNMPv1/SNMPv2c/SNMPv3 Agent
Icecast/SHOUTcast Client
Modbus/TCP client and server
WebSocket Client and Server
DHCPv6 Client
DHCPv6 Relay Agent
Ethernet MAC Driver Optional Optional Optional
Wi-Fi Driver Optional Optional Optional
PCAP Driver Optional Optional Optional
PPP (Point-to-Point Protocol) Optional Optional Optional
USB/RNDIS Driver Optional Optional Optional
G3-PLC driver Optional Optional Optional Optional
HTTP/2 client (1) Optional Optional Optional Optional
(1) The HTTP/2 client is available under ST Liberty Ultimate License for STM32 users. Refer to Alexa Voice Service software expansion for STM32Cube (X-CUBE-AVS).