The SCALE codec workbench

Every byte Quantus puts on the wire is SCALE-encoded — extrinsics, storage keys, RPC payloads. This lab lets you encode and decode the codec by hand: canonical compact integers in all four modes, every primitive, options / vecs / structs / enums, SS58 addresses on prefix 189, and twox_128 storage keys. Strict mode rejects non-canonical encodings — the same check that caught a real mode-2 decode bug in this builder's own tooling. Nothing leaves your browser.

Encode canonical

Enter an integer (decimal or 0x hex). The lab always emits the single canonical encoding — smallest mode, minimal bytes.

Integer

Decode strict

Paste compact bytes. Strict mode rejects non-canonical encodings (bloated modes, padded big-ints) — lax mode still decodes but flags them.

Hex bytes

strict

The four modes

The two low bits of the first byte select the mode. Click a notorious value to load it into the decoder.

Mode	First byte	Range	Example
single-byte	`xxxxxx00`	0 – 63	42 → a8
two-byte	`xxxxxx01`	64 – 16,383	69 → 1501
four-byte	`xxxxxx10`	16,384 – 2³⁰−1	16384 → 02000100
big-integer	`xxxxxx11`	2³⁰ – 2⁵³⁶−1	2³⁰ → 0300000040

Why strict matters. A decoder that doesn't check canonicality will happily read bloated encodings — and a decoder that mis-handles mode 2 (like this builder's own extrinsic decoder did before 2026-09-30) silently corrupts every amount between 16,384 and 1,073,741,823 plancks. When you verify someone else's bytes, decode strictly.

Schema struct builder

Build a struct field-by-field, fill in values, and encode it — or paste hex and decode it back with the same schema. Integers accept decimal or 0x hex (BigInt-safe); bytes/accountid accept hex; bool is true/false; str is plain text; balance is plancks (shown in QTC too).

Encode

Decode

Hex bytes

strict

Encode pubkey → SS58

32-byte public key as hex → Quantus SS58 address (prefix 189 → prefix bytes 6f40, checksum = blake2b-512("SS58PRE" ‖ body)[0..2]).

Public key (32 bytes hex)

Verify SS58 → anatomy

Paste any SS58 address. The lab checks the base58 alphabet, the prefix (warns if it isn't Quantus 189), the key length, and the checksum.

SS58 address

Plain storage key

twox_128(pallet) ‖ twox_128(item) — the 32-byte key for plain (non-map) storage values. The chain hashes with XxHash64 seeds 0 and 1 (verified against the chain's sp-crypto-hashing).

Pallet Storage item

Map storage key

Plain key + the map hasher applied to your key bytes: Blake2_128Concat (e.g. System.Account), Twox64Concat, or Identity.

Map key bytes (hex) Hasher

Tip: copy a forged key into the Chain Console's storage reader (state_getStorage) to read the value live from a node.

Canonical test vectors run live

The spec table this codec is held to. "Run all" executes every vector in your browser right now — green means this page's codec matches the canonical SCALE spec and the chain-verified hash anchors.

	Vector	Expected hex

Anchors. Compact/primitive vectors are the canonical parity-scale-codec spec table. twox_128("System") is cross-checked against @polkadot/util-crypto (2026-09-30). SS58 vectors round-trip through an independent node:crypto checksum check in the repo's test suite (tests/run-tests.mjs — 62 assertions).