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s404

Spark s404 Documentation

1. Overview

S404 Protocol introduces a dual-layer ownership model that links Bitcoin Ordinals inscriptions with Spark BTKN tokens.Every Ordinals NFT in s404 collection has exactly one matching BTKN token on Spark.

  • Ordinals NFTs on Bitcoin
  • BTKN tokens on Spark
  • Fixed 1:1 supply
  • Public bridge vaults
  • Tradable

This expreriment brings ERC-404-style “NFT ↔ token” behavior into the Bitcoin ecosystem while respecting Bitcoin’s immutability and UTXO model.

2. Architecture

2.1 Bitcoin Ordinals (NFT layer)

Each NFT in s404 collection is native Bitcoin Taproot inscription:

  • Immutable, permanent on-chain media
  • Stored directly on Bitcoin as an inscription
  • Owned by the user’s Ordinals address
  • Fully compatible with existing Ordinals infrastructure

2.2 Spark BTKN (token layer)

BTKN s404 token acts as the liquid representation of NFTs on Spark:

  • Fixed supply, equal to the total NFT collection size
  • 1 BTKN token represents 1 NFT
  • Fast and low-fee transfers on Spark
  • Designed for trading, DeFi, rewards, and utility

3. Supply Model

S404 strictly enforces supply parity:

Total BTKN Supply = Total Ordinal NFT Supply
  • No new BTKN tokens can be created
  • No new Ordinal NFTs are minted via the bridge (only via the original mint)
  • Ordinal NFTs and BTKN tokens are never burned, only locked in a bridge vault

This makes s404 different from fractional token models or dynamic supply standards:

No fractionalization.
No hidden minting.
Just a 1:1 mapping between each Ordinal inscription and each BTKN token.

4. Bridge Mechanism (Bitcoin Mainnet ↔ Spark)

S404 uses a pure locking model with two public bridge vaults:

  • Ordinals Bridge Vault on Bitcoin Mainnet — holds NFTs while their BTKN counterparts are circulating on Spark.
  • BTKN token Bridge Vault on Spark — holds BTKN tokens while their NFTs are circulating on Bitcoin.

Every movement between layers is a swap of custody: from user wallet → vault on one layer, and from vault → user wallet on the other.

4.1 NFT → BTKN (Bitcoin Mainnet → Spark)

  1. User sends a specific NFT inscription to the Ordinals Bridge Vault on Bitcoin.
  2. Bridge software detects the incoming inscription and validates it.
  3. The matching BTKN token (from fixed supply) is released from the Spark Bridge Vault.
  4. User receives BTKNtoken on Spark representing that NFT.
  5. The NFT remains safely locked in the Ordinals vault until redeemed.

4.2 BTKN → NFT (Spark → Bitcoin Mainnet)

  1. User sends BTKN to the Spark Bridge Vault.
  2. Bridge confirms the token is locked and ensures it belongs to the valid collection.
  3. The corresponding NFT is released from the Ordinals Bridge Vault on Bitcoin.
  4. NFT is sent to the user’s Ordinals address.

No token burning and no NFT minting. Protocol simply unlocks assets from vaults.

5. Supply Invariant & Security Model

The bridge maintains a simple, auditable invariant: 


Ordinals NFTs Locked in Bitcoin Mainnet Vault   = BTKN Circulating on Spark
BTKN token Locked in Spark Vault   = NFTs Circulating on Bitcoin

Anyone can verify at any time:

  • How many Ordinals NFTs are locked on Bitcoin Mainnet in the bridge vault
  • How many BTKN tokens are locked on the Spark vault
  • That the sum of circulating assets always equals the full collection supply
All bridge vault addresses are public.
The community can independently audit balances and confirm the 1:1 backing.

6. Wallet Integration (Xverse)

When a user connects Xverse Wallet, the protocol automatically detects the three relevant addresses:

Address Type Layer Usage
Payment address (BTC) Bitcoin Mainnet Network fees, app fees, and regular BTC payments.
Ordinals address (Taproot) Bitcoin Mainnet Receives inscriptions, holds the NFT collection, used for bridge operations.
Spark address Spark Holds BTKN tokens, pays Spark gas, interacts with protocols.

Since addresses are auto-detected from Xverse, users do not have to manually copy-paste or choose which address to use. The protocol routes actions to the correct address type and bridge vault.

7. Minting

The s404 collection is minted on Bitcoin as Ordinals inscriptions:

  • User mint Bitcoin Ordinals NFT to Xverse wallet.
  • Each mint uses fixed artwork / content for the s404 collection.
  • Every successful mint creates a unique inscription ID and can be tradable on marketplaces such as MagicEden, OKX and others after listing.

The system will automatically create BTKN token with the same amount as the NFT. 100% of the tokens will be in the bridge vault and ready for bridge. Once all Ordinals NFTs minted, they are bridge-ready and can be locked to receive their matching BTKN on Spark.

8. BTKN Token Utility on Spark

Because BTKN tokens represent Ordinals NFTs 1:1, they can integrate deeply with Spark’s ecosystem:

  • DEX Trading: Trade exposure to individual NFTs or the entire collection without moving inscriptions on Bitcoin.
  • Lending & Collateral: Use BTKN balances as collateral in Spark lending protocols.
  • Staking & Rewards: Build staking, points systems, and rewards based on BTKN holdings.
  • Airdrops & Whitelists: Snapshot Spark state to reward NFT owners without scanning UTXOs.

The key property: every BTKN is always backed by a real NFT, locked either in the bridge vault or in a user’s Ordinals wallet.

9. Staking

Spark s404 Staking is designed for both layers of s404: stake either the Bitcoin Ordinals NFT or the matching BTKN token on Spark and earn real BTC rewards. No lockups — stake/unstake anytime.

Preview interface: stake on Bitcoin (Ordinals) or on Spark (BTKN) — claim BTC rewards anytime.

Stake Ordinals NFTs (Bitcoin)

Connect your wallet and stake s404 Genesis as a native Bitcoin Ordinals inscription. Your NFT stays fully traceable on Bitcoin while participating in rewards.

Stake BTKN (Spark)

Stake the liquid s404 BTKN token on Spark for fast interactions, low fees, and the same reward logic tied to the 1:1 supply model.

9.1 How it works

  1. Choose staking mode: Ordinals NFT (Bitcoin) or BTKN (Spark).
  2. Stake your asset — no lockups, you can unstake anytime.
  3. Rewards accrue while your position remains staked.
  4. Claim rewards anytime without needing to unstake.
Flexible by design:
Stake / unstake anytime. Rewards accrue while staked. Claim independently.

9.2 APY & Rewards

Rewards are distributed based on an APY-style yield, allocated proportionally to your staked position. The APY is expressed as an annualized rate, while rewards accrue continuously over time.

  • APY-based: annualized rate used for transparent reward calculations
  • Proportional: larger / longer stakes earn more
  • No auto-compound: you decide when to claim
Note: APY and reward emissions can evolve as protocol incentives expand (BTC, protocol tokens, bonus rewards).

9.3 Claim rewards

Rewards are claimed on-demand. You can claim your accrued BTC rewards at any time without unstaking your Ordinals NFT or BTKN position.

  • Claim anytime
  • No need to unstake
  • Full user control (not auto-compounded)

9.4 Wallet support

At launch, Xverse will be the primary wallet integration for Bitcoin Ordinals staking. We’re actively working on adding more wallets over time to make staking accessible to more users across both Bitcoin and Spark.

  • Launch: Xverse for Ordinals + Spark address detection
  • Next: additional Bitcoin wallet integrations
  • Goal: seamless staking UX across more wallet providers

10. S404 vs ERC-404

S404 adapts the idea of “fungible token ↔ NFT” linkage to Bitcoin, but with a stricter and more transparent model.

Feature ERC-404 S404
Base chain Ethereum Bitcoin Mainnet + Spark
NFT type ERC721-like True Bitcoin Ordinals inscriptions
Token supply Can be dynamic, relies on mint/burn Fully fixed, equal to NFT collection size
Backing model Often fractional or synthetic 1:1 guaranteed
Bridge mechanism Typically none Dual public vault addresses
Transparency Depends on implementation Vault balances are fully visible and auditable

11. Summary

S404 Protocol defines a new hybrid asset standard:

  • Ordinals NFT collection on Bitcoin Mainnet
  • BTKN token on Spark
  • Both with fixed, equal supply
  • Both secured by public bridge vaults, not mint/burn logic
  • Both automatically tied to user addresses via Xverse Wallet integration

This enables instant liquidity on Spark, provable ownership on Bitcoin, and a clean, auditable bridge between the two layers.