Fractal Bitcoin

Fractal grew out of the 2023–2024 congestion around Ordinals, BRC-20 and Runes. Its January 2024 technical work proposed virtualizing Bitcoin Core rather than importing an EVM. Mainnet followed on 9 September with 30-second targets, Bitcoin-style UTXOs and addresses, and OP_CAT enabled for more expressive scripts.

Compatibility did not join the ledgers. Fractal maintains its own genesis, block history and FB balances; its documentation says a Fractal transaction cannot be replayed into Bitcoin because the UTXO sets differ. FB pays for this chain. A Bitcoin-looking address therefore says how keys and outputs are formatted, not that its balance is BTC or that Bitcoin nodes finalized it.

At launch, Cadence Mining assigned one block in each three-block rhythm to AuxPoW merge mining and two to open SHA256d mining. A Bitcoin pool could commit to a Fractal block while pursuing a Bitcoin block, reusing work without forcing every Bitcoin miner to participate.

FIP-101 later added a third producer. From height 1,500,000, the network trends toward one merge-mined block, one permissionless block and one indexer block. That change makes the security claim precise: Bitcoin hashpower can strengthen the AuxPoW lane, while Fractal’s own difficulty, indexer signatures and fork-choice rules decide the chain as a whole.

The 210,000,000 FB ceiling is ten times Bitcoin’s 21,000,000 headline cap and keeps eight decimal places. Fractal’s source code gives height 1 an exceptional subsidy of 105,000,000 FB. Separately, published tokenomics assigns the same total across a 15% ecosystem treasury, 10% community grants, 5% presale, 5% adviser reserve and 15% core contributors; the other 50% is the mining budget.

Treasury and grant funds are split across block-height locks over ten years. The published schedule provides a seven-month lock for presale and core-contributor allocations followed by linear release through month 12; this is not verification that every scheduled release occurred. After the exceptional first block, ordinary subsidy began at 25 FB. These are different release clocks: a maximum supply does not say how much is liquid, and a time lock does not say who will ultimately receive a grant or treasury payment. On 8 September 2025, the project said 2,086,848 FB from treasury and grant buckets had entered “Fractal Vault” after 1,000,000 FB was reserved for anniversary staking. Its “Preservation First” and “Exceptional Use Only” language describes policy; the announcement gives no Vault address, signers or enforceable withdrawal lock.

FIP-101 rewards indexers that maintain standardized data services. Users bind non-custodial Taproot stake to an indexer and share rewards by stake weight; delayed settlement is allowed so indexing cannot halt ordinary block production.

The block-production gate is less open than the phrase permissionless staking may suggest. An indexer proof needs a cold-key authorization, an expiring range, a hot-key signature and a small proof of work. Mainnet parameters embed the cold public key used to validate those authorizations. Users keep exit keys, but authorizing providers and assigning cursor ranges remains a distinct control point.

In September 2025, the project announced WFB on Ethereum. It placed 8,400,000 FB in a cross-chain program and said an initial 2,100,000 FB backed the first WFB issue. The verified ERC-20 has an 8,400,000 cap and is a UUPS proxy whose owner can mint, pause and replace the implementation. Live contract calls show that owner is a Safe requiring two of three signers. The 1:1 backing statement comes from the project announcement, which does not identify the native-FB custody address or a public mint-and-burn reconciliation process.

FIP-102, finalized on 18 August 2026, proposes another form: FB distributed natively on Bitcoin mainnet with a supply-neutral 1:1 conversion. At Fractal height 2,100,000 it also brings the Fractal-side reward down from 25 to 6.25 FB and allocates an equivalent 6.25-FB-per-Fractal-block budget to Bitcoin activity. On 5 September the explorer reported height 2,092,050, so none of that was yet an accomplished migration. FIP-103 still had to define eligible activity and conversion operations. FIP-102 budgets three to six months for implementation, with testing planned for Q4 2026 and full rollout targeted for Q1 2027; those are targets, and the reviewed FIPs tree contained no FIP-103 document.

Fractal Vote gives one voting unit for each locked FB. Holders may unlock after voting, but wait 21,000 blocks before claiming; the recorded vote remains valid. The interface makes preferences legible and the FIP process makes rule changes discussable.

Execution follows a longer chain of authority. Contributors write releases, the Foundation describes itself as the governance body, and node operators decide whether to run hard-fork software. The MiCAR paper calls FB a utility token with no value-protection or compensation scheme. FB can pay, stake and register a preference, but a holder cannot compel the next fork or claim Foundation assets. Fractal’s proposed Bitcoin-mainnet form becomes real only when FIP-103 code, operator adoption and a working custody path make that new boundary executable.