Velxio is a free online circuit simulator with real-time SPICE analog simulation in your browser. Drop resistors, capacitors, op-amps, transistors, diodes, and voltage regulators on the canvas — every component is modelled with real ngspice device cards, not behavioural stand-ins. Open Circuit Simulator →
+
+
ngspice-WASM engine — full Modified Nodal Analysis at ~60 Hz solve rate
+
Non-linear devices behave like real silicon: BJT cutoff/saturation, op-amp rails, diode forward drop
+
Live oscilloscope, voltmeter, ammeter, signal generator
Always-on — no toggle, every circuit is SPICE-solved
+
+
+
+
+
SPICE Simulator Online — ngspice in Your Browser
+
Velxio runs ngspice (the open-source SPICE simulator powering professional EDA tools) compiled to WebAssembly via eecircuit-engine. Full transient analysis, real device models, in your browser tab. No install, no account, works offline after the first load. Open SPICE Simulator →
+
+
Real ngspice — same engine, browser-native via WASM
+
5 BJTs (2N2222, 2N3055, 2N3906, BC547, BC557)
+
4 MOSFETs (2N7000, IRF540, IRF9540, FQP27P06)
+
5 op-amps (LM358, LM741, TL072, LM324, ideal) with saturation rails
Custom Chip Simulator — Define Your Own ICs in C / Rust
+
Velxio implements the Wokwi Custom Chips API: write your chip logic in C, Rust, or AssemblyScript, compile to WebAssembly, and the simulator drives its pins like any other component. Build a sensor model, a digital protocol bridge, or a behavioural IC stand-in — and reuse it across projects. Open Custom Chip Simulator →
+
+
Wokwi-compatible Custom Chips API with WASI shim
+
Pin reads/writes, attribute reads, timers
+
I²C and SPI bus integration
+
Save chips to your account and reuse across projects
+
Library of starter examples (sensors, decoders, bridges)
+
+
+
+
+
ATtiny85 Simulator — Real AVR Emulation in Your Browser
+
Velxio simulates the ATtiny85 with cycle-accurate AVR8 emulation. Full DIP-8 pinout, 8 KB flash, 6 GPIOs, USI peripheral, 10-bit ADC, Timer0/Timer1 with PWM, and watchdog. Wire it to LEDs, sensors, or analog circuits and run real ATtiny code without a programmer. Open ATtiny85 Simulator →
+
+
Cycle-accurate ATtiny85 emulation via avr8js
+
All 6 I/O pins (PB0–PB5) with proper port behaviour
+
Timer0 (8-bit), Timer1 (8-bit), watchdog timer
+
10-bit ADC with 4 input channels
+
USI peripheral for I²C / SPI bit-banging
+
Wire to SPICE analog parts for full circuit testing
+
+
+
Free Online Arduino Simulator
Velxio is a free online Arduino simulator with real AVR8 emulation at 16 MHz. Simulate Arduino code with 48+ interactive electronic components directly in your browser — no install, no account required. Open Arduino Simulator →
+ Free ATtiny85 Simulator
+
+ Cycle-accurate AVR emulation in your browser
+
+
+ Write Arduino code for the ATtiny85 and run it instantly — every AVR opcode is emulated
+ faithfully. All 6 I/O pins, USI for I²C/SPI, Timer0/Timer1 PWM, 10-bit ADC, watchdog.
+ Wire it to real SPICE analog circuits. Free, no install, no account.
+
+ Everything you need to develop ATtiny85 firmware without a programmer or breadboard.
+
+
+
+
Core
+
+ AVR 8-bit RISC, 8 KB flash, 512 B SRAM, 512 B EEPROM. DIP-8 pinout (PB0–PB5 plus
+ VCC/GND).
+
+
+
+
GPIO
+
+ 6 I/O pins on PORTB. Configurable as input / output / pull-up. Pin-change interrupts
+ (PCINT0–PCINT5) and external INT0.
+
+
+
+
Timers & PWM
+
+ Timer0 (8-bit) with two PWM channels on PB0/PB1. Timer1 (8-bit) with high-speed
+ mode and two PWM channels on PB1/PB4 — useful for higher-frequency PWM.
+
+
+
+
ADC
+
+ 10-bit ADC with 4 input channels (ADC0 on PB5, ADC1 on PB2, ADC2 on PB4, ADC3 on
+ PB3). Internal 1.1 V reference.
+
+
+
+
USI
+
+ Universal Serial Interface — bit-bangs I²C (TWI) and SPI. Compatible with TinyWireM
+ / TinyWireS and standard SPI libraries.
+
+
+
+
Watchdog & sleep
+
+ Watchdog timer with reset and interrupt modes. Power-down, ADC noise reduction, and
+ idle sleep modes — handy for low-power demos.
+
+
+
+
+
+ {/* What you can do */}
+
+
What can you build?
+
+ ATtiny85 projects shine when they're small, low-power, and analog-aware — exactly
+ Velxio's strength with the SPICE solver wired in.
+
+
+
+
Blink & PWM fade
+
+ The classic intros — hardware-PWM-driven LED fading on PB1 via Timer0, and
+ high-speed Timer1 PWM on PB4.
+
+
+
+
Button-driven LEDs
+
+ Read a button on PB2 with internal pull-up, debounce in firmware, drive an LED on
+ PB0.
+
+
+
+
NTC temperature
+
+ Read an NTC thermistor / fixed-resistor divider on ADC1 — the SPICE solver returns
+ the real divided voltage to analogRead().
+
+
+
+
I²C peripherals via USI
+
+ Talk to an OLED, an EEPROM, or an RTC on PB0/PB2 using TinyWireM. Bus traffic is
+ emulated end-to-end.
+
+
+
+
SPI WS2812 / shift
+
+ Bit-bang via USI to drive a WS2812 string or a 74HC595 shift register on a couple of
+ pins.
+
+
+
+
Analog switching
+
+ Drive a MOSFET gate from PB1 PWM through a SPICE-modelled gate-charge curve — see
+ the slew-rate effect on the load.
+
+
+
+
+
+ {/* FAQ */}
+
+
Frequently Asked Questions
+
+ {FAQ_ITEMS.map(({ q, a }) => (
+
+
{q}
+
{a}
+
+ ))}
+
+
+
+ {/* Bottom CTA */}
+
+
Develop ATtiny85 firmware without hardware
+
Open the editor and start coding — compile, simulate, and probe in seconds.
+ );
+};
diff --git a/frontend/src/pages/CircuitSimulatorPage.tsx b/frontend/src/pages/CircuitSimulatorPage.tsx
new file mode 100644
index 00000000..2ad51c95
--- /dev/null
+++ b/frontend/src/pages/CircuitSimulatorPage.tsx
@@ -0,0 +1,279 @@
+/**
+ * /circuit-simulator — SEO landing page
+ * Target keywords: "circuit simulator", "online circuit simulator",
+ * "free circuit simulator", "browser circuit simulator"
+ */
+
+import React from 'react';
+import { Link } from 'react-router-dom';
+import { AppHeader } from '../components/layout/AppHeader';
+import { useSEO } from '../utils/useSEO';
+import { getSeoMeta } from '../seoRoutes';
+import { trackClickCTA } from '../utils/analytics';
+import './SEOPage.css';
+
+const META = getSeoMeta('/circuit-simulator')!;
+
+const FAQ_ITEMS = [
+ {
+ q: 'Is this circuit simulator really free?',
+ a: 'Yes. Velxio is fully free and open-source under the GNU AGPLv3 license. No account required, no cloud subscription, no paywalled components — every part of the simulator runs in your browser.',
+ },
+ {
+ q: 'What kind of analog simulation does Velxio use?',
+ a: 'Velxio runs ngspice — the open-source SPICE simulator used by professional EDA tools — compiled to WebAssembly via eecircuit-engine. Each tick performs a full Modified Nodal Analysis solve, so non-linear devices (diodes, BJTs, MOSFETs, op-amps with saturation) behave like real silicon, not idealised approximations.',
+ },
+ {
+ q: 'Can I connect a microcontroller to my circuit?',
+ a: 'Yes — and this is the unique feature. GPIO pins drive SPICE nets as voltage sources, and ADC inputs read the solved analog node voltages back into your firmware. You can build a PWM-driven RC filter, a transistor switch, an op-amp signal chain, or a MOSFET motor driver and watch the firmware and circuit interact in real time.',
+ },
+ {
+ q: 'What components are available?',
+ a: 'Resistors, capacitors, inductors, potentiometers, photoresistors (LDR), photodiodes, NTC thermistors, batteries (9V/AA/coin), 5 BJTs (2N2222, 2N3055, 2N3906, BC547, BC557), 4 MOSFETs (2N7000, IRF540, IRF9540, FQP27P06), 5 op-amps (LM358, LM741, TL072, LM324, ideal), 4 linear regulators (7805, 7812, 7905, LM317), Zener and Schottky diodes, optocouplers (4N25, PC817), relays, L293D dual H-bridge driver, and 7 logic gates plus 7 74HC-series ICs as DIP-14 packages.',
+ },
+ {
+ q: 'Does the simulator have an oscilloscope and voltmeter?',
+ a: 'Yes. Velxio includes a multi-channel oscilloscope, voltmeter, ammeter, and signal generator (sine, square, DC) as live instruments you can drop on the canvas. They probe any node or wire and update in real time as the simulation runs.',
+ },
+ {
+ q: 'Is this a Falstad / CircuitLab / Tinkercad alternative?',
+ a: 'For analog circuits, yes — and a more accurate one, since Velxio runs the real ngspice engine instead of a simplified solver. Unlike those tools, Velxio also runs the firmware on the microcontroller driving the circuit, so you can validate firmware + hardware together without leaving the browser.',
+ },
+];
+
+const JSON_LD: object[] = [
+ {
+ '@context': 'https://schema.org',
+ '@type': 'SoftwareApplication',
+ name: 'Velxio — Free Online Circuit Simulator',
+ applicationCategory: 'DeveloperApplication',
+ applicationSubCategory: 'Electronics Simulator',
+ operatingSystem: 'Any (browser-based)',
+ description:
+ 'Free online circuit simulator with real-time SPICE analog simulation via ngspice-WASM. 100+ components co-simulated with Arduino, ESP32, RP2040, and ATtiny85 firmware. Live oscilloscope, voltmeter, ammeter.',
+ url: 'https://velxio.dev/circuit-simulator',
+ offers: { '@type': 'Offer', price: '0', priceCurrency: 'USD' },
+ author: { '@type': 'Person', name: 'David Montero Crespo' },
+ license: 'https://www.gnu.org/licenses/agpl-3.0.html',
+ },
+ {
+ '@context': 'https://schema.org',
+ '@type': 'FAQPage',
+ mainEntity: FAQ_ITEMS.map(({ q, a }) => ({
+ '@type': 'Question',
+ name: q,
+ acceptedAnswer: { '@type': 'Answer', text: a },
+ })),
+ },
+ {
+ '@context': 'https://schema.org',
+ '@type': 'BreadcrumbList',
+ itemListElement: [
+ { '@type': 'ListItem', position: 1, name: 'Velxio', item: 'https://velxio.dev/' },
+ {
+ '@type': 'ListItem',
+ position: 2,
+ name: 'Circuit Simulator',
+ item: 'https://velxio.dev/circuit-simulator',
+ },
+ ],
+ },
+];
+
+export const CircuitSimulatorPage: React.FC = () => {
+ useSEO({ ...META, jsonLd: JSON_LD });
+
+ return (
+
+
+
+ {/* Hero */}
+
+
+ Free Online Circuit Simulator
+
+ SPICE-accurate analog, in your browser
+
+
+ Drop resistors, capacitors, op-amps, transistors, and regulators on the canvas — every
+ part is solved by real ngspice running in WebAssembly. Wire it to Arduino, ESP32, or
+ Raspberry Pi Pico firmware and watch them co-simulate. Free, no install, no account.
+
+
+ trackClickCTA('circuit-simulator', '/editor')}
+ >
+ Open Circuit Simulator →
+
+
+ Browse 40+ Analog Examples
+
+
+
+ Free & open-source · Real ngspice engine · Runs 100% in your browser
+
+
+
+ {/* What */}
+
+
What can you simulate?
+
+ Velxio runs the real ngspice solver — the same engine professional EDA tools use — on
+ every tick. This is not a linear approximation. Diodes have proper forward drop, BJTs
+ cut off and saturate, op-amps hit their rails, regulators have dropout.
+
+
+
+
Passive networks
+
+ Voltage dividers, RC/RL/RLC filters, Wheatstone bridges, capacitor charging curves,
+ resonant tank circuits.
+
+
+
+
Diodes & rectifiers
+
+ Half-wave, full-wave bridge rectifiers, Zener regulators, voltage doublers,
+ clippers and clampers.
+
+
+
+
Transistor circuits
+
+ BJT common-emitter amplifiers, transistor switches, Darlington pairs, MOSFET drivers,
+ H-bridge motor drives, current mirrors.
+
+ Velxio uses ngspice-WASM via the
+ open-source eecircuit-engine. Every wire on the canvas becomes a SPICE net,
+ every component becomes a SPICE device card, and the solver runs full Modified Nodal
+ Analysis on each tick.
+
+
+
+
1. Wire
+
+ Drop components, drag wires. Velxio union-finds the wire graph into SPICE nets in
+ real time as you build.
+
+
+
+
2. Solve
+
+ ngspice solves the full circuit at ~60 Hz. Non-linear devices iterate to convergence
+ — no shortcuts, no idealisations.
+
+
+
+
3. Probe
+
+ Drop voltmeters, ammeters, or oscilloscope channels on any node. Live readings
+ update as the simulation runs.
+
+
+
+
+
+ {/* Co-simulation */}
+
+
The unique feature: hybrid digital + analog co-simulation
+
+ Most browser circuit simulators stop at passive analog. Velxio also runs the firmware on
+ the microcontroller driving the circuit — on the same clock.
+
+
+
+
GPIO drives the circuit
+
+ digitalWrite(HIGH) in your sketch sets a SPICE voltage source HIGH.
+ Drive a MOSFET gate, switch a relay, charge a capacitor through a resistor — all
+ from real firmware.
+
+
+
+
ADC reads the circuit
+
+ analogRead() returns the SPICE-solved voltage at the input node — after
+ the op-amp gain stage, after the divider, after the saturation. What you measure is
+ what the circuit produces.
+
+
+
+
Same canvas, same clock
+
+ Arduino + transistor + motor on the same board. ESP32 + photodiode + op-amp + ADC.
+ CH32V003 + Zener + LED. Validate firmware and hardware together before soldering.
+
+
+
+
+
+ {/* FAQ */}
+
+
Frequently Asked Questions
+
+ {FAQ_ITEMS.map(({ q, a }) => (
+
+
{q}
+
{a}
+
+ ))}
+
+
+
+ {/* Bottom CTA */}
+
+
Ready to simulate your circuit?
+
Open the editor and drop your first SPICE component in seconds — zero setup.
+ );
+};
diff --git a/frontend/src/pages/CustomChipSimulatorPage.tsx b/frontend/src/pages/CustomChipSimulatorPage.tsx
new file mode 100644
index 00000000..ae564e43
--- /dev/null
+++ b/frontend/src/pages/CustomChipSimulatorPage.tsx
@@ -0,0 +1,262 @@
+/**
+ * /custom-chip-simulator — SEO landing page
+ * Target keywords: "custom chip simulator", "custom chip arduino",
+ * "wokwi custom chips", "build custom ic"
+ */
+
+import React from 'react';
+import { Link } from 'react-router-dom';
+import { AppHeader } from '../components/layout/AppHeader';
+import { useSEO } from '../utils/useSEO';
+import { getSeoMeta } from '../seoRoutes';
+import { trackClickCTA } from '../utils/analytics';
+import './SEOPage.css';
+
+const META = getSeoMeta('/custom-chip-simulator')!;
+
+const FAQ_ITEMS = [
+ {
+ q: 'What is a custom chip in Velxio?',
+ a: 'A custom chip is a user-defined integrated circuit. You write the chip\'s logic in C, Rust, or AssemblyScript — Velxio compiles it to WebAssembly, instantiates it on the canvas like any other component, and drives its pins from the simulator.',
+ },
+ {
+ q: 'Which API does Velxio use?',
+ a: 'Velxio implements the Wokwi Custom Chips API — the same API used by Wokwi — so chips you write for Velxio are portable to Wokwi and vice versa. Velxio adds a WASI shim so you can use standard library functions in your chip code.',
+ },
+ {
+ q: 'What can I build?',
+ a: 'Behavioural models of real ICs (sensors, decoders, level translators, protocol bridges), custom digital logic, sensor stand-ins for hardware you don\'t have yet, and protocol-level mocks for testing firmware. Chips can drive pins, read attributes, register timers, and bridge to I²C / SPI buses.',
+ },
+ {
+ q: 'How do I share or reuse a chip?',
+ a: 'Save the chip to your Velxio account and reuse it across projects. The chip definition includes its pin layout, attributes, and the compiled WASM — drop it onto any project canvas like a built-in component.',
+ },
+ {
+ q: 'Do I need a backend to run my chip?',
+ a: 'No. Compiled chip WASM runs in the same browser tab as the rest of the simulation. Pin updates, attribute reads, and timer ticks are all local.',
+ },
+ {
+ q: 'Can my custom chip talk to an Arduino?',
+ a: 'Yes — that is the typical use case. Wire its pins to Arduino GPIOs, SPI, or I²C lines and the firmware on the Arduino interacts with your chip exactly like a real IC.',
+ },
+];
+
+const JSON_LD: object[] = [
+ {
+ '@context': 'https://schema.org',
+ '@type': 'SoftwareApplication',
+ name: 'Velxio — Free Online Custom Chip Simulator',
+ applicationCategory: 'DeveloperApplication',
+ applicationSubCategory: 'IC Authoring & Simulation',
+ operatingSystem: 'Any (browser-based)',
+ description:
+ 'Define your own integrated circuits in C, Rust, or AssemblyScript using the Wokwi-compatible Custom Chips API. Compile to WebAssembly and drive pins, attributes, timers, I²C and SPI from your simulated chip. Free and open-source.',
+ url: 'https://velxio.dev/custom-chip-simulator',
+ offers: { '@type': 'Offer', price: '0', priceCurrency: 'USD' },
+ author: { '@type': 'Person', name: 'David Montero Crespo' },
+ license: 'https://www.gnu.org/licenses/agpl-3.0.html',
+ },
+ {
+ '@context': 'https://schema.org',
+ '@type': 'FAQPage',
+ mainEntity: FAQ_ITEMS.map(({ q, a }) => ({
+ '@type': 'Question',
+ name: q,
+ acceptedAnswer: { '@type': 'Answer', text: a },
+ })),
+ },
+ {
+ '@context': 'https://schema.org',
+ '@type': 'BreadcrumbList',
+ itemListElement: [
+ { '@type': 'ListItem', position: 1, name: 'Velxio', item: 'https://velxio.dev/' },
+ {
+ '@type': 'ListItem',
+ position: 2,
+ name: 'Custom Chip Simulator',
+ item: 'https://velxio.dev/custom-chip-simulator',
+ },
+ ],
+ },
+];
+
+export const CustomChipSimulatorPage: React.FC = () => {
+ useSEO({ ...META, jsonLd: JSON_LD });
+
+ return (
+
+
+
+ {/* Hero */}
+
+
+ Build Your Own Custom Chips
+
+ in C, Rust or AssemblyScript
+
+
+ Define your own integrated circuits with the Wokwi-compatible Custom Chips API. Write
+ the chip in C, Rust, or AssemblyScript; Velxio compiles it to WebAssembly and runs it on
+ the canvas like any other component — driven by Arduino, ESP32, or RP2040 firmware.
+
+
+ trackClickCTA('custom-chip-simulator', '/editor')}
+ >
+ Open the Editor →
+
+
+ Read the Docs
+
+
+
+ Wokwi-compatible API · Free & open-source · WASM-powered, runs in your browser
+
+
+
+ {/* What you can do */}
+
+
What can you build?
+
+ Custom chips fill the gaps between built-in components. If a real IC isn't on the
+ shelf, build a behavioural model and your firmware never knows the difference.
+
+
+
+
Sensor stand-ins
+
+ Mock a temperature, pressure, or IMU sensor that responds over I²C — useful when
+ you don't have the part yet but want to develop the firmware.
+
+
+
+
Protocol bridges
+
+ Build a UART-to-I²C bridge, an SPI shift register, a digital-to-analog wrapper, or
+ a custom level translator.
+
+
+
+
Custom logic
+
+ Glue logic, state machines, address decoders, debouncers — anything you'd otherwise
+ wire up with discrete gates.
+
+
+
+
Behavioural ICs
+
+ Re-create the externally-visible behaviour of a real IC (a 7-segment driver, a
+ stepper controller) without simulating its analog internals.
+
+
+
+
Test fixtures
+
+ Inject signals on schedule, capture pin transitions, validate firmware against
+ expected pin-level behaviour.
+
+
+
+
Reusable libraries
+
+ Save the chip to your account, import it into other projects, share with the
+ community.
+
+
+
+
+
+ {/* API capabilities */}
+
+
What the API gives you
+
+ The Velxio Custom Chips runtime is fully Wokwi-compatible, with extras for the SPICE
+ and multi-board environment.
+
+
+
+
Pin I/O
+
+ Read pin state, write digital high/low, configure pull-ups, react to edges with
+ pin-watch callbacks.
+
+
+
+
Attributes
+
+ Read user-configurable chip attributes from the property panel — values, strings,
+ numbers — and re-read on change.
+
+
+
+
Timers
+
+ Schedule callbacks at microsecond resolution. The runtime fires them aligned to the
+ simulator clock.
+
+
+
+
I²C bus
+
+ Connect to any wire that's part of an I²C bus, respond to start/stop conditions,
+ acknowledge addresses, send / receive bytes.
+
+
+
+
SPI bus
+
+ Bidirectional SPI with chip-select handling. Implement a shift register, an SPI
+ memory, or a sensor with one byte-stream callback.
+
+
+
+
WASI shim
+
+ A small WASI shim lets your C/Rust chip use standard-library calls (printf, string
+ ops, math) without a heavy runtime.
+
+
+
+
+
+ {/* FAQ */}
+
+
Frequently Asked Questions
+
+ {FAQ_ITEMS.map(({ q, a }) => (
+
+
{q}
+
{a}
+
+ ))}
+
+
+
+ {/* Bottom CTA */}
+
+
Build your first custom chip
+
Open the editor and create a chip in seconds — pick C, Rust, or AssemblyScript.
+ );
+};
diff --git a/frontend/src/pages/ElectronicsSimulatorPage.tsx b/frontend/src/pages/ElectronicsSimulatorPage.tsx
new file mode 100644
index 00000000..861a6260
--- /dev/null
+++ b/frontend/src/pages/ElectronicsSimulatorPage.tsx
@@ -0,0 +1,240 @@
+/**
+ * /electronics-simulator — SEO landing page
+ * Target keywords: "electronics simulator", "online electronics simulator",
+ * "free electronics simulator", "online breadboard"
+ */
+
+import React from 'react';
+import { Link } from 'react-router-dom';
+import { AppHeader } from '../components/layout/AppHeader';
+import { useSEO } from '../utils/useSEO';
+import { getSeoMeta } from '../seoRoutes';
+import { trackClickCTA } from '../utils/analytics';
+import './SEOPage.css';
+
+const META = getSeoMeta('/electronics-simulator')!;
+
+const FAQ_ITEMS = [
+ {
+ q: 'Is Velxio a complete electronics simulator?',
+ a: 'Yes. Velxio combines a SPICE-accurate analog solver, 19 simulated microcontrollers (Arduino, ESP32, RP2040, ATtiny85, Raspberry Pi 3), 100+ components, an oscilloscope, voltmeter, ammeter, and signal generator — everything you need to design and validate an electronics project end-to-end.',
+ },
+ {
+ q: 'Can I use it like a virtual breadboard?',
+ a: 'Yes. Drop components on the canvas, drag wires between pins, and the simulator builds the SPICE netlist automatically. Wires snap to a grid; components rotate in 90° increments; signal-type colours mark VCC, GND, digital, and analog routes.',
+ },
+ {
+ q: 'Do I need to install anything?',
+ a: 'No. Open velxio.dev in any modern browser and start. Compilation of Arduino sketches uses the cloud arduino-cli backend, but the SPICE solver and AVR / RP2040 / RISC-V emulators all run locally in your browser.',
+ },
+ {
+ q: 'Is it good for teaching electronics?',
+ a: 'Yes — that is one of the design goals. Free, no install, no account, no licence cost. 100+ pre-wired example circuits cover voltage dividers, RC filters, op-amp amplifiers, transistor switches, rectifiers, and complete Arduino projects. Great for university labs and self-learners.',
+ },
+ {
+ q: 'Is Velxio a Tinkercad / Falstad alternative?',
+ a: 'Yes — and a more accurate one. Velxio runs real ngspice (the engine professional EDA tools use), and unlike those tools it also runs the firmware on the microcontroller driving the circuit. Open-source under AGPLv3.',
+ },
+];
+
+const JSON_LD: object[] = [
+ {
+ '@context': 'https://schema.org',
+ '@type': 'SoftwareApplication',
+ name: 'Velxio — Free Online Electronics Simulator',
+ applicationCategory: 'DeveloperApplication',
+ applicationSubCategory: 'Electronics Simulator',
+ operatingSystem: 'Any (browser-based)',
+ description:
+ 'Free online electronics simulator. SPICE-accurate analog parts wired to 19 simulated microcontrollers. 100+ components, oscilloscope, voltmeter, ammeter — your virtual breadboard.',
+ url: 'https://velxio.dev/electronics-simulator',
+ offers: { '@type': 'Offer', price: '0', priceCurrency: 'USD' },
+ author: { '@type': 'Person', name: 'David Montero Crespo' },
+ license: 'https://www.gnu.org/licenses/agpl-3.0.html',
+ },
+ {
+ '@context': 'https://schema.org',
+ '@type': 'FAQPage',
+ mainEntity: FAQ_ITEMS.map(({ q, a }) => ({
+ '@type': 'Question',
+ name: q,
+ acceptedAnswer: { '@type': 'Answer', text: a },
+ })),
+ },
+ {
+ '@context': 'https://schema.org',
+ '@type': 'BreadcrumbList',
+ itemListElement: [
+ { '@type': 'ListItem', position: 1, name: 'Velxio', item: 'https://velxio.dev/' },
+ {
+ '@type': 'ListItem',
+ position: 2,
+ name: 'Electronics Simulator',
+ item: 'https://velxio.dev/electronics-simulator',
+ },
+ ],
+ },
+];
+
+export const ElectronicsSimulatorPage: React.FC = () => {
+ useSEO({ ...META, jsonLd: JSON_LD });
+
+ return (
+
+
+
+ {/* Hero */}
+
+
+ Free Online Electronics Simulator
+
+ Build, wire and test in your browser
+
+
+ A complete electronics workbench: SPICE-accurate analog parts, 19 simulated
+ microcontrollers (Arduino, ESP32, RP2040, ATtiny85, Raspberry Pi 3), 100+ components,
+ and live instruments — all in one canvas. Free, no install, no account.
+