What is the difference between transparent and shielded?

Transparent funds work like Bitcoin's UTXO ledger — public amounts and addresses anyone can audit. Shielded funds live as encrypted notes inside the Orchard pool; nullifiers stop double-spends without revealing the note, and validity is proven by zk-SNARKs (Halo 2) with no trusted setup.

Does it connect to a real Zcash node?

The sandbox simulates execution so it's safe to experiment. For every script it also generates the real zcash-cli commands, so you can run the exact same logic on your own node when you're ready.

Free · runs in your browser · no signup

See value turn private.

Q: What is ZKstacks?

ZKstacks is a free, browser-based educational sandbox. You step through real Zcash scripts on a visual stack machine, watch each opcode execute, and see transparent funds turn shielded inside the Orchard pool — making abstract zero-knowledge concepts visible and hands-on.

Q: Do I need to install anything?

No. ZKstacks runs entirely in your browser with zero setup. It's free, with 20+ ready-made scripts you can run instantly.

Q: What is a Zcash stack machine and an opcode?

Zcash transparent transactions are unlocked by a small script — opcodes like OP_DUP, OP_HASH160 and OP_CHECKSIG that push and pop values on a stack. The script must resolve to TRUE for the coins to move. ZKstacks animates that stack so you can watch it happen step by step.

Zcash scripting and zero-knowledge can look like pure magic. ZKstacks makes them visible — step through real scripts on a visual stack machine and watch transparent funds shield into the Orchard pool.

Launch the sandbox — free ▶ Try it on this page

100+ opcodes20+ scripts0 setupHalo 2 · no trusted setup

Opcodes. Shielded pools. SNARK proofs. Powerful — but invisible. So we made them move.

01 — EXECUTE

Watch every opcode fire.

Step through a real script and watch the stack mutate in real time — duplicate, hash, verify — until the funds unlock. The model finally clicks because you can see it.

<Sig> <PubKey> → OP_DUP → OP_HASH160 → OP_EQUALVERIFY → OP_CHECKSIG → TRUE

The ZKstacks stack machine animating Zcash opcodes pushing and popping values until a script resolves to TRUE

02 — Learn

One workspace, three panes.

Pick a script in the editor, step it on the stack visualizer, and read why each opcode satisfies Zcash consensus from the built-in mentor — then copy the real zcash-cli to run it for yourself.

ZKSTACKS Zcash Visual Sandbox Standard P2PKH ▾

Editor & Builder

Direct editorBuilder

1<Signature>2<PublicKey>3OP_DUP4OP_HASH1605OP_EQUALVERIFY6OP_CHECKSIG

Stack Visualizer

STEP 4 / 7▶ Step

<PublicKey>PUBKEY

a91f…e3HASH

Mentor & CLI

Step analysis · OP_HASH160

Hashes the public key with SHA-256 then RIPEMD-160, producing the 20-byte address fingerprint to compare against.

$ zcash-cli signrawtransaction
    "<hex_from_step_1>"
$ zcash-cli sendrawtransaction
    "<signed_hex>"

Choose or write a script

20+ ready examples, or build your own.

Step the machine

Watch each opcode mutate the stack.

Learn from the mentor

Plain-English consensus context.

Copy real zcash-cli

Run the same logic on a node.

t-address · public ledger

Transparent

Public amounts & addresses — anyone can audit the chain.
Works exactly like Bitcoin's UTXO ledger.
Unlocked with classic Script — signatures & hashes.

z-address · orchard pool

Shielded

Value sealed inside an encrypted note.
Nullifiers stop double-spends without revealing the note.
Validity proven by zk-SNARKs (Halo 2) — no trusted setup.

OP_DUPOP_HASH160OP_CHECKSIGOP_EQUALVERIFYOP_SWAPOP_ROTOP_CHECKMULTISIGOP_IFOP_TOALTSTACKGENERATE_SNARK_PROOFOP_SHA256CREATE_SHIELDED_OUTPUTOP_BOOLANDVERIFY_SNARK_PROOFOP_NUMEQUALPROVE_OWNERSHIP

Real depth

A real opcode playground.

From basic arithmetic to shielded SNARK operations — every opcode is colour-coded by category and executes live on the stack. 100+ supported, across 20+ ready-made scripts.

Opcode Library 100+ supported

Constants Stack Logic Crypto Shielded

Constants

01OP_1NEGATE<Signature><PublicKey><Preimage>

Stack

OP_DUPOP_DROPOP_SWAPOP_OVEROP_ROTOP_TOALTSTACK

Logic

OP_EQUALOP_EQUALVERIFYOP_IFOP_ELSEOP_NUMEQUALOP_BOOLAND

Crypto

OP_SHA256OP_HASH160OP_HASH256OP_CHECKSIGOP_CHECKMULTISIGOP_CLTV

Shielded

CREATE_SHIELDED_OUTPUTGENERATE_SNARK_PROOFVERIFY_SNARK_PROOFPROVE_OWNERSHIP

100+ opcodes20+ ready-made scripts2 stacks · main + altNU5 consensus rules

The "aha"

Watch a script unlock funds.

Standard P2PKH — the most common Zcash transparent spend — animated opcode by opcode until the stack resolves to TRUE.

↑ <Sig> <PubKey>

The spender supplies a signature and the matching public key.

# OP_DUP

Duplicate the public key so we can hash a copy.

# OP_HASH160

a91f…e3

Hash the copy → the 20-byte address fingerprint.

✓ OP_EQUALVERIFY

Fingerprint matches the address — or the script aborts.

✓ OP_CHECKSIG

TRUE ✓

Signature verifies against the key → funds unlock.

Try the real thing

The sandbox, right here.

This is the actual ZKstacks stack machine — not a screenshot. Open the full app, or preview it inline, then pick a script and step the opcodes yourself.

zkstacks · /app — visual stack machine open full-screen ↗

Open the visual stack machine

Jump straight into the full ZKstacks app — editor, stack visualizer & mentor.

Open the stack machine → Free · runs locally · nothing leaves your browser

The 30-second film

From magic to muscle memory.

Script, stack, shield, ship — the whole idea in half a minute, sound on.

▶ Watch · 0:30

100+

Opcodes supported

20+

Ready-made scripts

Setup / install

Free

In your browser

FAQ

Good questions.

What is ZKstacks?

A free, browser-based educational sandbox. You step through real Zcash scripts on a visual stack machine, watch each opcode execute, and see transparent funds turn shielded inside the Orchard pool — making abstract zero-knowledge concepts visible and hands-on.

Do I need to install anything?

No. ZKstacks runs entirely in your browser with zero setup, and it's free, with 20+ ready-made scripts you can run instantly.

What's a stack machine and an opcode?

Zcash transparent spends are unlocked by a small script — opcodes like OP_DUP, OP_HASH160 and OP_CHECKSIG that push and pop values on a stack. The script must resolve to TRUE for coins to move. ZKstacks animates that stack so you can watch it happen.

Transparent vs shielded — what's the difference?

Transparent funds behave like Bitcoin's UTXO ledger — public amounts and addresses. Shielded funds are encrypted notes in the Orchard pool; nullifiers prevent double-spends without revealing the note, and validity is proven by zk-SNARKs (Halo 2) with no trusted setup.

Does it connect to a real node?

The sandbox simulates execution so it's safe to experiment. For every script it generates the real zcash-cli commands, so you can run the exact same logic on your own node when you're ready.

Stop guessing. Start seeing.

Watch Zcash work.

Free, in your browser, no signup. Open a script and step the stack in the next ten seconds.

Launch ZKstacks — free Watch the film