Product Licensing

CycloneTCP is available under 3 separate licensing models:

  • Open source version (CycloneTCP Open)
  • Evaluation version (CycloneTCP Eval)
  • Commercial version (CycloneTCP Lite, Pro or Ultimate)

Open Source License (GPLv2)

The open source version CycloneTCP Open is licensed under GPL version 2. This is ideal for evaluating CycloneTCP, for private use, or for integrating exclusively with other GPL software.


If you intend to distribute your software and link CycloneTCP 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 CycloneTCP internally, and not distributing any products containing CycloneTCP, 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 CycloneTCP 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.

Evaluation License

If the GPL license cannot be considered for evaluating CycloneTCP (because your project links to non GPL-compatible third party software), then you may consider the evaluation license CycloneTCP 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 this 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 this software. If you wish to extend the evaluation period, you must contact our sales department.

Commercial License

The product is also available under a commercial license (CycloneTCP 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.

Depending on your application, 3 distinct versions are available:

  • 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 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 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.

Feature Comparison


CycloneTCP
Open
CycloneTCP
Eval
CycloneTCP
Lite
CycloneTCP
Pro
CycloneTCP
Ultimate
LicenseOpen sourceEvaluationCommercialCommercialCommercial
Time-limited (90 days)NoYesNoNoNo
Source codeYYYYY
Royalty freeYN/AYYY
Doxygen documentationYYYYY
PDF user's manualNOptionalYYY
Support and maintenanceNOptionalYYY

CycloneTCP
Open
CycloneTCP
Eval
CycloneTCP
Lite
CycloneTCP
Pro
CycloneTCP
Ultimate
ARPYYYYY
IPv4YYYYY
ICMPYYYYY
IGMPv2YYYYY
IP fragmentation and reassemblyYYYYY
UDPYYYYY
TCPYYYYY
BSD socketsYYYYY
Auto-IPYYYYY
DHCP clientYYYYY
DNS clientYYYYY
NetBIOS responderYYYYY
mDNSYYYYY
VLAN (802.1q)YYYYY
TFTP client and serverYYYYY
DHCP serverYYNYY
DNS-SDYYNYY
FTP client and serverYYNYY
HTTP serverYYNYY
MQTT clientYYNYY
MQTT-SN clientYYNYY
CoAP clientYYNYY
SMTP clientYYNYY
SNTP clientYYNYY
SNMPv1/SNMPv2c/SNMPv3 agentYYNYY
Icecast/SHOUTcast clientYYNYY
Modbus/TCP client and serverYYNYY
WebSocket client and serverYYNYY
IPv6YYNNY
NDPYYNNY
ICMPv6YYNNY
MLDv1YYNNY
SLAACYYNNY
DHCPv6 clientYYNNY
DHCPv6 relay agentYYNNY
Ethernet MAC driverYYOptionalOptionalOptional
Wi-Fi driverYYOptionalOptionalOptional
PCAP driverYYOptionalOptionalOptional
PPP (Point-to-Point Protocol)YYOptionalOptionalOptional
USB/RNDIS driverYYOptionalOptionalOptional
G3-PLC driverNOptionalOptionalOptionalOptional
HTTP/2 client (1)NOptionalOptionalOptionalOptional


(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).