▶ RSpice · Analog & RF circuit simulation
The analog simulator, rebuilt.
RSpice is a ground-up SPICE engine written in Rust, validated point-for-point against ngspice on a 113-deck regression corpus. RF analyses, a Verilog-A compiler, Python automation — one engine that ships native, in the browser, and on the bench.
Oracle-validated
Every release is diffed point-for-point against ngspice-46 on a 113-deck regression corpus — rerunnable from a clean checkout.
Compact models, compiled
A built-in Verilog-A compiler ships BSIM4.8 as a compiled model — and takes your foundry's .va decks, NDA and all.
Deterministic by design
Seeded Monte Carlo, reproducible runs, a memory-safe Rust core — the same deck gives the same answer, every time.
Analyses
Everything on the bench, from .OP to phase noise.
The core engine covers the full SPICE repertoire. The RF suite — the analyses that usually cost five figures a seat — is one Pro license. Labels show how each one is reached: netlist card, CLI flag, or engine API.
Operating point
.opNewton with gmin and source stepping for stubborn convergence.
DC sweep
.dcTwo-source nested sweeps, temperature sweeps, and .STEP parameter families.
AC small-signal
.acComplex MNA magnitude and phase, with .TF gain / Zin / Zout.
Transient
.tranAdaptive timestep with TRAP and Gear, breakpoint-accurate sources.
Noise
.noiseInput- and output-referred spot and integrated noise.
Monte Carlo
--monte-carloProcess and mismatch draws with gauss / agauss, seeded and exactly reproducible.
Parametric step
.stepSweep any parameter; overlay families of curves in one run.
S-parameters
engine apiMultiport network analysis with Touchstone export, from the Rust API.
Verilog-A models
compile-vaCompiled compact models — BSIM4.8 ships as Verilog-A; bring your foundry's .va decks.
Harmonic balance
PRO--hb-freqMulti-tone steady state for mixers, PAs, and large-signal RF.
Periodic steady state
PRO--pss-freqShooting PSS for oscillators and switched circuits.
PNoise & PAC
PROengine apiPhase noise and periodic AC around the steady state.
One engine · three surfaces
The same solver, everywhere you work.
One Rust codebase compiles to native desktop, WebAssembly, and touch devices. Same netlist, same numerics, same answer on all three.
Native desktop
Windows, macOS, and Linux. GPU-drawn canvas, fully offline — your license is a signed key, not a phone-home.
In the browser
The full engine compiled to WebAssembly. Nothing to install, nothing uploaded — decks simulate on your own silicon.
Tablet & mobile
The browser build is touch-first on tablets — review schematics and carry last night's Monte Carlo to the lab bench.
Validation
Trust is a regression suite, not a slogan.
A simulator earns its place by agreeing with the simulators you already trust — then by being honest when it doesn't. RSpice is developed against independent oracles on locked time grids, so a passing deck means numerically the same waveform, not "looks close".
- ngspice-46 parity — the regression corpus runs both engines on identical grids and diffs every point of every probe.
- Analytic RF oracles — harmonic balance and shooting-PSS are pinned to closed-form decks; the Verilog-A BSIM4 is pinned to ngspice's native BSIM4 bias-for-bias.
- Open corpus — the 113 validation decks come from the ngspice example corpus and published test suites, so you can rerun the evidence yourself.
Pricing
Free where it should be. Paid where it earns it.
The core simulator is free — including commercial use. You pay when RSpice replaces a five-figure RF seat, not before.
Community
$0 forever
- All core analyses — op, dc, ac, tran, noise, MC, step
- Native + browser apps
- Schematic, netlist, waveforms
- SPICE raw · CSV · HDF5 · JSON output
- Commercial use allowed
Pro
$499 / year · per engineer
- Everything in Community
- RF suite — HB, PSS, PNoise, PAC
- Python automation API
- Priority support
Team
Per seatearly access
- Everything in Pro
- Cloud simulation runners
- Shared libraries & PDK sync
- Pooled, reassignable seats
Enterprise
Custom
- Floating & offline licenses
- Air-gapped installs
- On-prem cloud runners
- Procurement, SLAs, escrow
licenses are signed keys that work offline — no account, no telemetry, no phone-home. checkout opens with v1.0.0; until then, the GitHub repo is the front door.
Get started
Press run.
Open the browser app and simulate your first deck before your coffee cools — or download the free Community edition.