FIP-101: Proposal (revised)
Status: Draft 2.0 FIP Number: 101 Title: Fractal Standard Indexing Service Author: UniSat Team Created: 2025-12-31 Type: Standard Proposal (Consensus Layer) License: BSD-2-Clause
Abstract
This proposal introduces the Fractal Standard Indexing Service, aiming to provide Fractal Bitcoin with an open-source, permissionless, standardized indexing service maintained by core contributors and integrated into the Fractal block reward system.
By reallocating block reward distribution and introducing a Taproot-based non-custodial staking mechanism, this proposal ensures the long-term stability, decentralization, and sustainable operation of indexing infrastructure, while preserving network liveness and minimizing impact on existing consensus processes.
Proposal Summary
Open Participation: Anyone may operate indexing services permissionlessly. Miners and mining pools may also participate by running index nodes or joining the staking mechanism.
Reward Reallocation: Adjust block reward distribution from the current 1:2 (Merged Mining : Permissionless Mining) to 1:1:1 (Merged Mining : Permissionless Mining : Indexing).
Non-custodial Staking: Users stake FB through Taproot scripts. Funds always remain under user private-key control. Users may exit and migrate between indexing instances without operator permission.
Non-blocking Settlement: Index verification and reward settlement must not enter the block production critical path. Index rewards may be processed asynchronously or with delay to preserve chain liveness.
Progressive Activation: Node support is deployed first and observed across the network.
Motivation
Lack of Standardization in High-Performance Indexing
Currently, multiple indexing solutions exist within the Fractal community, including both commercial and open-source implementations. However:
Protocol parsing logic and output formats are inconsistent
Maintenance costs remain high
No unified standard interface or data structure has emerged
This fragmentation introduces uncertainty and significantly increases integration costs for application developers.
The Optimal Timing to Introduce Standardized Indexing
Over the past two quarters, UniSat Team, as a core contributor to Fractal Bitcoin, has conducted extensive refactoring of its production indexing system, achieving:
Approximately 80% reduction in memory usage
Initial synchronization completion within 24 hours, significantly faster than many existing open-source solutions
Substantially reduced hardware requirements and operational barriers
The maturity of this infrastructure now enables a transition toward a fully open, community-operated standardized indexing framework.
The Urgent Need for Standardization
Without timely standardization:
Protocol interpretation may fragment across different implementations
Developers will be forced to maintain redundant parsing logic
Integration errors and ecosystem inconsistency risks will increase
Standardized indexing has become a necessary foundation for Fractal’s sustainable expansion.
Design Overview
Indexing as the Third Pillar of Network Infrastructure
From a network architecture perspective:
Merged Mining provides security
Permissionless Mining ensures openness and decentralization
Indexing enables data availability, composability, and application usability
Indexing reliability and availability are infrastructure-level requirements comparable to network security and decentralization, and therefore require long-term economic incentives.
Open Participation and Replaceability
Indexing software will be open-source
Participation is permissionless
Standardized output formats allow applications to switch between different implementations, reducing vendor lock-in risks
Non-custodial Staking and Exit Guarantees
Users stake FB to specific indexing instances to participate in reward distribution
Staking is implemented using Taproot scripts
Funds remain under user private-key control at all times
Users may exit and migrate between indexing services
No slashing mechanism is introduced in this proposal
Non-blocking Block Production and Asynchronous Settlement
Indexing infrastructure may experience downtime, network partitions, or temporary verification issues. Therefore:
Indexing failures must not affect block production
Index reward settlement may be delayed
Long-term reward distribution converges toward target ratios without impacting chain liveness
Goals & Non-Goals
Goals
Reduce indexing fragmentation through unified base standards
Establish sustainable incentives for long-term indexing operation
Lower operational barriers to encourage decentralized participation
Minimize trust assumptions via non-custodial staking
Limit changes to consensus structure and reduce risk exposure
Non-Goals
This proposal does not modify:
Block size or core block structure
UTXO model
Script language
PoW or difficulty adjustment
Total issuance, emission rate, or halving schedule
This proposal does not attempt to standardize:
Front-end APIs or SDKs
Specific protocol rule definitions
Application-layer data schemas
This proposal focuses solely on chain-level incentives and indexing infrastructure standards.
Tokenomics & Incentives
Reward Distribution Adjustment (1:2 → 1:1:1)
Current distribution:
Merged Mining: 1
Permissionless Mining: 2
Proposed distribution:
Merged Mining: 1
Permissionless Mining: 1
Indexing: 1
Total issuance and emission schedule remain unchanged.
Rationale for 1:1:1 Allocation
Security, openness, and data availability collectively define Fractal’s long-term sustainability.
Indexing infrastructure exhibits strong public-goods characteristics. Reliance on centralized services or short-term subsidies cannot provide durable supply.
The proposed ratio represents a long-term statistical target, guiding capital allocation and infrastructure investment. It may be evaluated continuously based on network performance and ecosystem feedback.
Participation Roles
Index Operators: Any entity (individuals, teams, miners, pools, institutions) may operate indexing instances and charge service fees
Stakers: Any user may stake FB into indexing services to participate in reward distribution
Specification
Reward Allocation Rules
Target ratio: 1:1:1 (Merged Mining : Permissionless Mining : Data Indexing)
Allocation applies in long-term statistical terms
Emission rate and total supply remain unchanged
Staking and Exit
Rewards are distributed proportionally by stake share
Implemented via Taproot scripts
Users may exit without operator cooperation
No slashing is introduced
Minimum stake thresholds apply
Weighting rules, service fee limits, script paths, and exit conditions will be specified in implementation documents
Reward Settlement and Delay
Settlement must remain outside the block production critical path
Minimum release delay: 7 days (~20,000 blocks)
Operators may charge limited service fees
Validity and Verification
The system must define:
Objective criteria for valid indexing results
Automatic reward suspension for invalid or offline instances
Reorg handling and rollback consistency
Proof formats, dispute resolution processes, and verification cycles
Failure Handling and Recovery
Chain must remain operational even during large-scale index downtime
Rewards pause automatically when indexing instances fail
Recovery mechanisms allow catch-up settlement and long-term convergence
Proposed FIP-101 Execution Process:
Introduce the node upgrade that enforces the consensus mechanism change and enables the subsequent reward distribution change.
Develop and open-source a lightweight indexer which would ensure data availability and allow anyone to join in the testing of the indexer and staking mechanism. We recommend this step to undergo a longer period of careful development and comprehensive testing to ensure that the system is intact.
The full standard indexing system is live with staking and reward distribution activated.
Security & Backward Compatibility
Security Considerations
Chain liveness: Indexing must never block block production
Reward abuse prevention: Objective validity rules and delayed settlement
Fund security: Non-custodial Taproot staking with user-controlled exits
Reorg consistency: Index rollback and replay handling must be deterministic and verifiable
Upgrade Impact
After activation:
Block rewards follow 1:1:1 distribution
Mining nodes must upgrade to remain consensus-compatible
Non-upgraded miners may produce invalid blocks rejected by upgraded nodes
No changes are made to:
Emission schedule
PoW or difficulty
Block structure
UTXO model
Script language
Reference Implementation
Reference implementation will include:
Core indexing engine
Pluggable protocol parsers
Storage layer
RPC query interfaces
Standardized coinbase output templates
Taproot staking script templates
Operational documentation will be provided covering:
Index deployment
Staking and exit flows
Migration procedures
Common failure scenarios
All components will be maintained as open-source repositories on GitHub.
UniSat Team
updated: 2026/01/24
Last updated