Sometimes we get the question from students and non-pro users: Why pay for Sigasi Visual HDL? Adding the claim: TerosHDL does “the same” for free

TL;DR

We wanted to verify that claim, did a full investigation and made a comparison feature by feature on the difference between Sigasi Visual HDL and TerosHDL. This comparison was made based on publicly available documentation, our friends at ChatGPT, Gemini, Claude, Perplexity,… and user feedback. It becomes clear that TerosHDL does not match the capabilities and features of Sigasi Visual HDL and that the claim is not correct.

Intro: “Free” is not without costs

First of all, “free” means that the license to use the software doesn’t come with an upfront license cost. Setting up an HDL development environment, especially for large projects, can be very expensive if you need time to figure it all out by yourself. Therefore, our excellent support team is glad to give you all the support you need included in the license fee to set-up your project hassle free. No more searching, asking, restarting and… losing time and money. We guarantee you a smooth start with Sigasi. Before you decide to start you can request a trial and we will give you a full demo to assist you with setting up your project. Click here to get going with your demo and full featured trial license.

Feature comparison

🧩 Integration

	TerosHDL	Sigasi Visual HDL
VS Code IDE Extension
Advanced Scalable Set-up
Project Management Config Tools
Semantic, Hierarchy-aware Code Navigation
Professional Project Setup Support
Git Version Control

🧠 Intelligent Code Assist

	TerosHDL	Sigasi Visual HDL
Folding
Semantic Highlighting
(Quick) Outline
Structural Selection
Open Design Unit
Find References
Go to Implementation
(Ranged) Formatting/indenting
Elaboration Hierarchy View
Syntax Checking (*)
Real-time (Syntax) Error Checking
Smart Indentation
Full Autocomplete
Context-aware IntelliSense Autocomplete
Semantic Occurrence Highlighting
Progress Reporting
Memory Monitoring
Go to Definition/Declaration in VHDL
Go to Definition/Declaration in Verilog/SV
Configurable Formatting
Class Hierarchy
Elaboration Hierarchy View
Libraries View
Code Lenses
Hovers
Hover Actions

(*) TerosHDL depends on seperate tools for syntax checking

✅ Compliance Assist

	TerosHDL	Sigasi Visual HDL
Quick Fixes
Linting (*)
Real-time Linting
Cross-file Linting

(*) TerosHDL depends on seperate tools for linting

✨ Design Assist

	TerosHDL	Sigasi Visual HDL
Tools & Libraries
Signature Helper
Documentation (Pre)View
Semantic Errors
Rename Refactoring for VHDL
Rename Refactoring for Verilog/SV
Net Search
Template Autocomplete
Context-aware Template Autocomplete
Preprocessor Autocomplete
Preprocessor View
Preprocessor Hover

🖼️ Graphic Assist & Visualization

	TerosHDL	Sigasi Visual HDL
Dependencies Diagram
Block Diagram (*)
Finite State Machines (FSM) Diagram
Real-time & Interactive FSM Diagram
Built-in Design Graphics Export
Design Hierarchy Export
Interactive Outline View

(*) TerosHDL depends on seperate tools for Block Diagram View

🛠 Verification Assist

	TerosHDL	Sigasi Visual HDL
UVM Linting
UVM Topology View
UVM Diagram

📚 Doc Assist

(only in Sigasi Visual HDL Enterprise Edition)

	TerosHDL	Sigasi Visual HDL
Single File Doc Generation
Full Project Documentation Generation

💸 CLI Task Assist

(only in Sigasi Visual HDL Enterprise Edition)

	TerosHDL	Sigasi Visual HDL
CLI Lint Reporting
CLI Documentation Generation
CLI Dependency Generation
CLI Diagram Generation
CLI Library Extraction
CLI VHDL Formatting

📋 Support

	TerosHDL	Sigasi Visual HDL
User Manual
Local Assistance in USA
Local Assistance in Germany & DACH
Local Assistance in UK, Ireland & Nordics
Local Assistance in India
Local Assistance in Türkiye
Local Assistance in Benelux & France
Professional Support

🎯 Conclusion

Sigasi Visual HDL is a purpose-built tool for professional FPGA & ASIC development, with advanced real-time parsing of your code as you type. It detects syntax errors and understands signal scopes, types, and hierarchy. It’s like having a reviewer, linter, and navigator working in real time fully integrated with other commercial tools. Professional project set-up support is included in the license fee. Node-locked and Floating Licenses are available. Sigasi is a medium-sized privately funded company founded in 2008, aimed at improving hardware designers’ work and saving money and time for chip designing companies. On average four major releases are made per year. The current version is 2025.2, which was released in June 2025. The new 2025.3 release is expected in September 2025.
TerosHDL is a lightweight, underpowered open-source IDE for FPGA students, hobbyists, and independent designers with limited resources that can’t spend money on a tool that makes them work faster and better. It lacks semantic understanding and deeper design insights. Teros Technology was funded through the European Commission’s Next Generation Internet programme, under grant agreement No 957073. On average, one major release was done per year. There is no information about a planned future release.
Sigasi Community Edition is the full version of Visual HDL for students, academics and non-commercial users. We understand a license fee for a professional tool like Sigasi can be too expensive for non-professional users. Therefore, we decided to introduce a Community Edition (CE) for students, teachers, and all other non-commercial users so they can learn and experience the advantages of Sigasi when designing a chip. When these students graduate, they have the advantage of being able to work in their professional environment with the tool they already know. The only difference between CE and the Professional Edition is that Talkback must be enabled in CE and info is send back to Sigasi for improvement of our tool. No professional support is included in the Community Edition.

You want to try out Sigasi Visual HDL?

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Sigasi Visual HDL vs TerosHDL