TRex

At a glance

• Editor score
  8.3 / 10
• Pricing
  Free plan
• Best for
  Open-source high-scale traffic generation
• Free plan
  Yes
• Paid from
  Free
• Deployment
  Self_hosted
• Facts checked
  20 Sep 2026

• Where it wins

  • Generates scalable stateful and stateless TCP/UDP traffic
  • Replays PCAPs and traffic templates with detailed statistics
  • Automates tests through Python and JSON-RPC APIs

• Where it doesn't

  • Self-hosted deployment places operations on the testing team
  • Engineering-focused workflows may require networking expertise
  • Not suited to teams seeking a managed hosted testing service

Our verdict on TRex

TRex is an open-source network traffic generator for testing routers, switches, firewalls, load balancers, DPI systems, and other network infrastructure. It is aimed at engineering teams that need high-scale stateful, stateless, advanced stateful, or emulation workloads across L3–L7 traffic. The platform uses DPDK and runs as a self-managed Linux application, with virtualized and Docker-based deployment options. Its free, open-source model makes it a fit for teams that can manage their own test environment and automation stack.

Traffic-generation depth is the main strength. Stateful workloads can replay traffic templates, while stateless packet streams support field modification. Advanced TCP and UDP generation, PCAP import, export, replay, and capture support cover several common test workflows. TRex also measures latency, jitter, flow ordering, and per-stream statistics. L2 client emulation and protocol plugins extend testing across TCP, UDP, ARP, ICMP, IPv6/ND, DHCPv4/v6, IGMP, DNS, DOT1X, LLDP, mDNS, NetFlow/IPFIX, OSPF, RIP, and GTP-U. This breadth makes it suitable for infrastructure validation rather than only simple packet-rate checks.

Automation and deployment fit are equally important. The Python automation API and JSON-RPC control over ZMQ allow TRex to integrate with scripted test systems and programmatic workflows. Web, Windows, macOS, Linux, and API access are listed as supported platforms, while the published deployment description centers on self-managed Linux, virtualization, and Docker. Teams should choose TRex when they value open-source control, protocol breadth, PCAP workflows, and scalable traffic generation. Teams seeking a hosted service, guided onboarding, or a simpler point-and-click testing experience should consider a different type of product.

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TRex pricing

TRex fact sheet

Alternatives to TRex

• Cisco ThousandEyesBroad enterprise coverage for testing networks, applications, traffic, routes, DNS, and topology.9.4
• NetBeezA wide-ranging platform for continuous, scheduled, and Wi-Fi network monitoring.9.2
• Forward EnterpriseA strong choice for modeling network behavior, testing changes, and tracing dependencies.9.0

See all TRex alternatives →

Featured on iTechGuides

TRex is listed in our Network Testing Software directory. Add the badge to your site — it links back to this page.

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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Last updated 7 Oct 2026 · How we research and update