Is this online Verilog compiler free?

Yes, EcrioniX Online Verilog Compiler is completely free with no limits. No account, no signup, no credit card. Write Verilog or SystemVerilog in the browser editor and run it instantly — simulation, synthesis, and waveform viewing are all free.

What Verilog simulator does EcrioniX use?

EcrioniX uses Icarus Verilog (iverilog) as the simulation backend. Icarus Verilog is the industry-standard open-source Verilog simulator supporting Verilog-1995, Verilog-2001, Verilog-2005, and a broad SystemVerilog subset.

Does this online compiler support SystemVerilog?

Yes. The compiler supports SystemVerilog RTL constructs including always_ff, always_comb, always_latch, logic type, bit, byte, int, packed/unpacked arrays, typedef, enum, struct, union, interfaces, and modports. Most synthesizable SystemVerilog RTL works out of the box.

What is the Yosys synthesis feature?

Click Synth to run Yosys open-source RTL synthesis on your design. It reports the number of flip-flops, combinational cells, and memory elements, and the Netlist tab shows the gate-level circuit as an interactive SVG diagram you can pan, zoom, and download.

Is EcrioniX an EDA Playground alternative?

Yes. EcrioniX Verilog Compiler offers similar free online Verilog simulation but adds features EDA Playground lacks: a built-in interactive waveform viewer, Yosys synthesis, gate-level netlist diagram viewer, and no account required for any feature.

Verilog Online Simulator — Free Browser-Based HDL IDE

Q: How do I view waveforms in the online Verilog simulator?

Add $dumpfile('dump.vcd') and $dumpvars(0, tb) to your testbench. After clicking Run, the built-in waveform viewer opens automatically. You can zoom, scroll, click to set a cursor, and read exact signal values at any simulation time.

EcrioniX is a free Verilog online simulator powered by Icarus Verilog and Yosys. Write Verilog or SystemVerilog in the browser editor, simulate with an interactive waveform viewer, and synthesize to a gate-level netlist — all without installing any software. No signup, no credit card, no limits. The fastest way to simulate Verilog online and a direct EDA Playground alternative.

Features — Why Use EcrioniX?

Interactive Waveform Viewer

Parse VCD output from your testbench and view signal waveforms with zoom, scroll, and a live cursor readout. Add $dumpfile and $dumpvars to any testbench — no external tool needed.

Yosys RTL Synthesis

Click Synth to run Yosys open-source synthesis. Get a gate-count report — flip-flops, LUTs, muxes — and see exactly how your Verilog maps to standard logic cells.

Gate-Level Netlist Diagram

View the synthesized gate-level circuit as an interactive SVG diagram. Pan, zoom, and download the netlist — perfect for VLSI assignments and design reviews.

SystemVerilog Support

Compile always_ff, always_comb, logic, enums, structs, packed arrays, and interfaces. No separate SV compiler needed — one tool covers both Verilog and SystemVerilog.

Shareable Code Links

Click Share to generate a URL that encodes your entire multi-file project. Send to colleagues, embed in Stack Overflow answers, or link from GitHub issues.

Multi-File Projects

Add multiple .v files in one session — separate design files from testbenches. Synthesis automatically detects and skips tb.v files so only your RTL is synthesized.

EcrioniX vs EDA Playground — Feature Comparison

Feature	EcrioniX Verilog Compiler	EDA Playground
Free to use	✓ Completely free	✓ Free tier
Account / login required	✓ None — run instantly	✗ Account needed to save work
Icarus Verilog simulation	✓	✓
SystemVerilog support	✓	✓
Built-in waveform viewer	✓ Inline, no new tab	⚠ External EPWave (separate tab)
Yosys RTL synthesis	✓ Gate-count report	✗ Not available
Gate-level netlist diagram	✓ Interactive SVG	✗ Not available
Shareable code links	✓ No login needed	✓ Requires account
Download VCD waveform	✓ One click	⚠ Manual
Multi-file editing	✓	✓
VLSI learning content	✓ Full RTL/STA/VLSI site	✗ Tool only

How to Use the Online Verilog Compiler

Write or Load Code

Type Verilog or SystemVerilog in the editor, or click an example button — Counter, DFF, Adder, MUX, FSM, or SPI Master — to load a ready-to-run design.

Add a Testbench

Click + New File and add a testbench. Include $dumpfile("dump.vcd"); and $dumpvars(0,tb); to enable the waveform viewer.

Run Simulation

Press Run (or Ctrl+Enter). The console shows $display output and the waveform viewer opens automatically when VCD data is generated.

Synthesize (Optional)

Click Synth to run Yosys. Check the Synthesis tab for gate counts and the Netlist tab for the interactive gate-level circuit diagram.

Share or Download

Click Share to copy a permalink, or Download to save your .v source file or the VCD waveform data to your local machine.

Frequently Asked Questions

Is this online Verilog compiler really free?

Yes — completely free with no hidden limits, no account, no credit card. Write Verilog or SystemVerilog and click Run. Simulation, waveform viewing, Yosys synthesis, and netlist diagrams are all free. EcrioniX is funded by ads and dedicated to free semiconductor education.

What Verilog standard does EcrioniX support?

EcrioniX uses Icarus Verilog, which supports Verilog-1995, Verilog-2001, and Verilog-2005 standards. It also supports a broad SystemVerilog subset: always_ff, always_comb, always_latch, logic, bit, byte, int, packed/unpacked arrays, typedef, enum, struct, interfaces, and modports. Most synthesizable SV RTL works out of the box.

How do I view waveforms in the online Verilog simulator?

Add two lines at the start of your testbench initial block: $dumpfile("dump.vcd"); followed by $dumpvars(0, tb); where tb is your testbench module name. After clicking Run, the Waveform tab opens automatically. You can zoom with the mouse wheel, scroll horizontally, move the cursor to read exact values, and download the VCD file.

What is Yosys synthesis and why should I use it?

Yosys is an open-source RTL synthesis framework that maps your Verilog to logic gates (AND, OR, flip-flops, muxes). Clicking Synth gives you a report showing how many flip-flops, combinational cells, and memory elements your RTL infers. This is useful for learning how RTL synthesizes, checking for unintentional latches, estimating area, and understanding the difference between behavioral and gate-level descriptions.

Can I compile and run SystemVerilog code online?

Yes. EcrioniX supports SystemVerilog RTL constructs: always_ff, always_comb, always_latch, the logic type, bit, byte, int, shortint, longint, packed and unpacked arrays, typedef, enum, struct, union, interfaces, and modports. If you are writing synthesizable SystemVerilog for ASIC or FPGA, EcrioniX handles the standard RTL constructs used in production designs.

How is EcrioniX different from EDA Playground?

EcrioniX adds features EDA Playground does not have: (1) Built-in waveform viewer — no need to open EPWave in a separate tab. (2) Yosys RTL synthesis with a gate-count report. (3) Gate-level netlist SVG diagram you can pan, zoom, and download. (4) No account required for any feature — Run, Synth, Netlist, Share all work instantly. (5) Integrated with comprehensive VLSI learning content covering RTL design, STA, protocols, and ASIC flows at ecrionix.org.