Pebble + Gerolamo - HLabs 2026 Budget

Harmonic Laboratories (HLabs for short) is an R&D firm born and focused solely on the Cardano ecosystem.

Harmonic Laboratories supports and maintains a considerable portion of the TypeScript tooling for the Cardano ecosystem, which the majority of Cardano developers use, either directly, or indirectly via other libraries that depend on code written and maintained by HLabs.

The mission of HLabs is for true decentralization to become the baseline of application development, not only a nice-to-have feature.

Duration & Milestones

This proposal spans over 12 months, throughout which there will be several deliveries and demos. Amongst the key deliveries, we note:

• maintenance for an upcoming hard fork;
• a production-ready light node (Gerolamo);
• a production-ready, imperative and efficient, programming language for smart contracts (pebble).

Total Budget Ask

The estimated USD budget is of $2,250,000 (or ₳6,428,571) + 25% in refundable contingency (₳1,607,143); for a total ask of 8,035,714 ADA.

Ecosystem benefits

Gerolamo, Pebble, and ongoing tooling maintenance each serve distinct stakeholders while collectively strengthening Cardano's infrastructure, developer and user experience, and long-term sustainability.

Who will benefit from Gerolamo?

TL;DR

• dApps for trust-minimized applications
• wallets for daedalus-like security
• SPOs for relay nodes

dApps

Decentralized applications benefit immensely from trust-minimized access to blockchain data. Currently, most dApps rely on centralized indexers or third-party APIs to query the chain state, introducing points of failure and trust assumptions that undermine the decentralization ethos.

Gerolamo enables dApps to run their own lightweight nodes; even directly in the browser; providing direct, trustless access to the Cardano ledger.

This means dApps can verify UTxO states, validate transactions, and query chain data without relying on external services. The result is a more resilient, censorship-resistant application architecture that aligns with the core principles of decentralization.

Light wallets

Light wallets today must trust external servers to provide accurate chain data. This creates a security trade-off: users gain convenience but sacrifice the ability to independently verify their balances and transaction history.

With Gerolamo, wallet developers can integrate a lightweight node directly into their applications, offering users Daedalus-like security guarantees without the overhead of running a full node. Users can verify their own UTxOs, validate incoming transactions, and maintain full sovereignty over their funds, all while enjoying the user experience of a light wallet.

SPOs

Stake Pool Operators can use Gerolamo as an additional relay node alongside their existing infrastructure. Block production continues on their current setup, while Gerolamo relays add diversity and resilience to their pool.

A diverse node implementation landscape strengthens the network's resilience. By providing an alternative codebase for relays, Gerolamo reduces the risk of network-wide issues stemming from bugs in a single implementation; a critical factor for long-term network health and decentralization.

Who will benefit from Pebble?

TL;DR

Developers who seek an alternative to functional programming without sacrificing efficiency.

The language aims to be as similar as possible to TypeScript, which is a widely adopted language used in Web2, as well as similar to languages used in other, more mature ecosystems, such as Solidity on EVM chains.

Onboarding Web2 developers

One of Cardano's greatest challenges is the steep learning curve for smart contract development. Aiken, the most widely adopted smart contract language on Cardano, while a great improvement compared to haskell, still requires familiarity with functional programming paradigms, concepts unfamiliar to the vast majority of developers worldwide. This barrier significantly limits the pool of talent that can contribute to Cardano's dApp ecosystem.

Pebble bridges this gap by offering a syntax and development experience familiar to TypeScript and JavaScript developers, the largest programming communities in the world. By lowering the barrier to entry, Pebble opens Cardano development to millions of developers who would otherwise be deterred by the functional programming learning curve.

Efficient on-chain code

Despite its imperative syntax, Pebble compiles to highly optimized UPLC (Untyped Plutus Core). Developers don't have to choose between familiarity and efficiency: Pebble delivers both. The compiler performs aggressive optimizations to minimize execution costs, ensuring that contracts written in Pebble are competitive with hand-optimized Plutus code, making them a viable choice for production applications.

Professional development experience

Pebble's tooling, including a full Language Server Protocol (LSP) implementation, CLI with watch mode, and integrated debugging via sourcemaps, provides a development experience on par with mature ecosystems. Developers can enjoy auto-completion, inline error reporting, go-to-definition, and all the conveniences they expect from modern IDEs. This professional-grade tooling accelerates development cycles and reduces bugs, ultimately leading to higher-quality dApps on Cardano.

Who will benefit from the tooling maintenance?

TL;DR

The entire ecosystem can have the guarantee that there will always be up-to-date, easy to use, tools for them to use, without the fear of having to redesign entire applications because of missing support.

Ecosystem-wide stability

The TypeScript tooling maintained by HLabs underpins a significant portion of Cardano's developer ecosystem. Libraries like cardano-ledger-ts, ouroboros-miniprotocols-ts, and uplc are dependencies for numerous projects—both directly and transitively through other libraries. When a hard fork introduces protocol changes, these foundational libraries must be updated promptly, or downstream projects face breaking changes and potential security vulnerabilities.

By funding ongoing maintenance, the Treasury ensures that the TypeScript ecosystem remains synchronized with protocol upgrades. Developers can trust that their applications will continue to function across hard forks without emergency rewrites or extended downtime.

Reducing fragmentation risk

Without dedicated maintenance, critical libraries risk abandonment, a common fate in open-source ecosystems.

Abandoned dependencies force teams to either fork and maintain code themselves (duplicating effort across the ecosystem) or migrate to alternative solutions (fragmenting the developer community). Both outcomes are costly and destabilizing.

Sustained funding for HLabs tooling maintenance eliminates this risk, providing the ecosystem with a reliable foundation upon which developers can confidently build long-term projects.

Cardano 2030 Alignment

This proposal directly supports the Cardano 2030 Strategic Framework, contributing to core KPIs and strategic pillars as outlined below.

Alignment with Core KPIs

Note: The first two rows are formal Cardano 2030 KPIs. The third row corresponds to Strategic Pillar A.3 (Developer Experience → Education & migration), which is an explicit 2030 priority but not yet a numeric KPI. TVL, monthly transactions, and MAU are ecosystem-level outcomes enabled by infrastructure investments like this proposal; we track adoption indicators (below) as leading metrics that contribute to these outcomes.

Alignment with Strategic Pillars

Pillar 1: Infrastructure & Research Excellence

• I.2 Security & Resilience → Client Diversity: Gerolamo is explicitly aligned with the 2030 goal of supporting additional full-node and light-client implementations to achieve better decentralization and reduce single-client risk.

Pillar 2: Adoption & Utility

• A.3 Developer Experience → Open-source incentives: This proposal directly addresses the strategic priority to incentivize the maintenance of core Cardano SDKs, frameworks, and infrastructure in line with open-source best practices for a sustainable builder ecosystem.
• A.3 Developer Experience → Education & migration: Pebble addresses the goal to provide materials for EVM/account-based devs moving to Cardano/UTxO by offering familiar imperative syntax, enabling more developers to onboard.

Measurable Adoption Indicators

To provide visibility into how this proposal contributes to ecosystem-level outcomes, we commit to tracking and reporting the following adoption metrics:

Gerolamo Adoption Targets

Pebble Adoption Targets

Budget Breakdown

The full budget breakdown is given below.

For a fair valuation of the proposal, we will follow a similar process to what is used in the Amaru proposal, which we believe is setting a good standard in terms of Treasury budget proposals, and we will estimate the scopes of this proposal in FTE (Full-Time Equivalent), which we will consider to equal a figure of $225k yearly rate.

We use a conversion rate of 0.35 ADA [₳] per USD [$].

Complete View

Cost Rationale

The total ask for the project is 10 FTEs.

FTEs are being valued at an annual rate of $225k.

Furthermore, we are aware of our assumption/optimism bias (our forecast is subject to underestimating complexity, overlooking challenges, and undervaluing the time and cost required to deliver, as well as our biased expectation of market movements). We therefore add an extra 25% contingency buffer, learning by our past mistakes.

This leaves us with the following total: (10 x $225k) x 1.25 = $2,812,500

Finally, using a conversion rate of 0.35 ADA per USD, we formulate a budget ask of ₳8,035,714. A complete breakdown of this budget is available below.

Milestones

This proposal spans Q2 2026 through Q1 2027, with milestones organized by quarter.

Q2 2026 (Apr–Jun): Hard Fork Readiness & Foundations

• Hard-fork maintenance: all TypeScript libraries updated for the upcoming hard fork
• Gerolamo: improve storage and networking for browser environments;
• Pebble: complete the type system; support for upcoming hard fork changes

Completion evidence:

• All relevant libraries maintained by HLabs support the Hardfork
• Gerolamo syncs to tip on public test network
• Multiple (≥3) pebble contracts of various complexity compiled end-to-end to valid on-chain code

Q3 2026 (Jul–Sep): Core Delivery

• Gerolamo: initial server-side relay capable release
• Pebble: additional key language features, such as namespaces, tests and more comprehensive standard library

Completion evidence:

• Gerolamo server-side relay syncs and follows chain tip on public test network
• Gerolamo relay published as installable release
• New language features implemented (e.g. namespaces, tests, standard library)

Q4 2026 (Oct–Nov): Integration & Browser Support

• Gerolamo: browser light node capable of syncing and serving chain data; compatibility with existing Cardano tooling
• Pebble: complete IDE integration & CLI + push for developers onboarding

Completion evidence:

• Browser demo syncing and querying chain data without a backend server
• Standard Cardano tool (cardano-cli or cardano-db-sync) successfully connects to Gerolamo
• Pebble IDE extension published with syntax highlighting and inline errors
• Pebble CLI build command working on multiple projects

Q1 2027 (Dec–Mar): Production Readiness, Documentation & Adoption

• Gerolamo: production-ready browser light node; performance validation
• Pebble: interactive console, documentation, tutorials

Completion evidence:

• Major browsers where Gerolamo runs as a light node (Chromium etc.)
• Gerolamo browser node reaches a trustless tip, eventually over multiple sessions
• Gerolamo maintains stable peer connections for ≥24 hours
• Pebble language features documented with examples
• End-to-end tutorials published

Budget Administration and Governance Oversight

Smart Contract Escrow

Funds are held and released through the SundaeLabs treasury-contracts (https://github.com/SundaeSwap-finance/treasury-contracts), a proven framework with two validators:

treasury.ak: Holds all ADA withdrawn from the Cardano treasury. Everything gets locked here when the governance action is enacted.
vendor.ak: Manages milestone-based vesting for HLabs. Payment schedule, payout dates, release conditions.
Both contracts have been independently audited by TxPipe and MLabs and are in production use on mainnet.

Independent Oversight Board

An independent oversight board provides third-party governance:

Santiago Carmuega (TxPipe, Dolos)
Lucas Rosa (Aiken, Starstream, Midnight)
Chris Gianelloni (BlinkLabs, Dingo)

Board members don't have a stake in HLabs. They co-sign disbursements, review milestones, and can halt funding if we're not delivering.

Permission Scheme

The actions allowed by the escrow contract are as follows:

Disburse (periodic release): HLabs initiates + any 1 board member co-signs

Sweep early (return unused funds): HLabs + any 1 board member

Reorganize (adjust milestone schedule): HLabs only

Fund (initial vendor setup): Board majority

Pause milestone: Any 1 board member

Resume milestone: Board majority

Modify project: HLabs + board majority

Day-to-day operations need one board signature. Structural changes need the full board. And any single member can hit pause if something looks off.

Delegation Policy

The treasury contract enforces auto-abstain DRep delegation and no SPO delegation for all funds in escrow. Treasury funds don't influence governance votes or staking.

Failsafe Sweep

Funds left in the contract after expiration automatically sweep back to the Cardano treasury. Enforced at the contract level. Can't be overridden.

Constitutionality Checklist

In an effort to convince ourselves of the proposal's constitutionality, we thought relevant to include a checklist of the points we cover and for each, our interpretation of the Cardano Constitution.

Purpose

• [x] This proposal is for work intended to enhance the security, decentralization and long-term sustainability of Cardano.

Article II, Section 6: Governance Action Standards

• [x] We have submitted this proposal in a standardized, legible format, which includes a URL and hash of all documented off-chain content. We believe our rationale to be detailed and sufficient. The proposal contains a title, abstract, justification, and relevant supporting materials.

Article II, Section 7: Treasury Withdrawals Action Standards

• [x] Section 7.1 — This proposal specifies the purpose of the withdrawal, the 12-month delivery period, the relevant costs and expenses, and the circumstances under which the withdrawal might be refunded to the Cardano Treasury.

• [x] Section 7.2 — A full retrospective of past funding and deliverables is available in the 2025 retrospective document.

• [x] Section 7.5 — This proposal designates administrators (the oversight board) responsible for monitoring fund usage and ensuring deliverables are achieved.

• [x] Section 7.6 — Treasury funds held by the administrator prior to disbursement will be kept in separate auditable accounts, delegated to the predefined always_abstain voting option.

Treasury Withdrawal Guardrails

• [x] TREASURY-02a — This withdrawal shall not exceed the Net Change Limit for the relevant period.

• [x] TREASURY-03a — This withdrawal is denominated in ada.

• [x] TREASURY-04a — We acknowledge this action requires greater than 50% of DRep active voting stake to be ratified.

  Cardano 2030 Strategic Alignment

• [x] This proposal directly supports the Cardano 2030 Strategic Framework, contributing to the Alternative full node clients KPI (Pillar 1: Security & Resilience) and Developer Experience priorities (Pillar 2: Adoption & Utility).

• [x] Measurable adoption indicators have been defined to provide visibility into ecosystem-level KPI contributions (TVL, monthly transactions, MAU).

Budget Detailed View

Gerolamo (Typescript cardano node)

repo

Gerolamo is a TypeScript implementation of the Cardano node designed for:
- Browser compatibility: Serving as a base for nodes running in browsers
- Extensibility: Being the base for purpose-specific nodes (light nodes, UTxO-only nodes, chain indexers)

Full Ledger Rules Coverage

Goal

Implement complete ledger validation rules to enable Gerolamo to fully validate blocks and transactions according to the Cardano protocol specifications.

Key Results

• Full ledger state management using LMDB (or IndexedDB for browsers) for performance improvements.
• Consensus implementation (Praos) with chain selection and rollback handling
• Volatile DB for managing chain forks
• Block and transaction validation covering all eras

Estimated Effort

2.5 FTEs

Node APIs

Goal

Provide comprehensive APIs for dApp developers and infrastructure operators to interact with the Cardano network through Gerolamo.

Key Results

• UTxO RPC endpoints for efficient UTxO queries
• Local socket support for node-to-client protocols (cardano-db-sync, cardano-cli compatibility)
• Browser API for dApps to use

Estimated Effort

2 FTEs

Plutus Machine Improvements

Goal

Continuously improve the plutus-machine CEK interpreter for better performance and full conformance with the Plutus specification.

Key Results

• Performance optimizations for script evaluation
• Budget tracking and cost model accuracy improvements
• Sourcemap support for debugging

Estimated Effort

0.5 FTEs

Gerolamo Summary

• total resources estimated: 5 FTEs

Production Readiness Criteria

Gerolamo will be considered production-ready as a browser light node when it meets the following objective criteria:

Value Proposition vs. Other Node Implementations

[!NOTE]
Gerolamo is designed as a complementary implementation focused on browser light node and data-node use cases, not a replacement for block-producing nodes yet. Block production so far remains on the Haskell node.

Getting to a point where the node can be considered seriously as a production-ready light node, functionality wise, should get us pretty close to a point where it can also be used for block production.

however, enabling block production in a mainnet environment, would incur in a serious increase in the funds we would need to ask

for the security audit alone, the amaru and blinklabs teams are asking an additional 500k USD, which we believe to be appropriate.

additionally, if we were to include block production between the goal of this year, we'd also need to increase the estimated effort by at least 1 more FTE.

should the condition allow the next year, block production will be strongly considered.

given the current environment we decided it would be best to cut those efforts in order to contain the costs.

Pebble (smart contract programming language)

repo

Pebble is a simple, yet rock solid, functional language with an imperative bias, targeting UPLC (Untyped Plutus Core). It provides developers with an intuitive syntax while compiling to highly optimized on-chain code.

Compiler Stability

Goal

Achieve production-grade compiler stability with optimized code generation.

Key Results

• Comprehensive type system with full type inference
• Optimized UPLC code generation with minimal script sizes
• Complete error reporting with actionable messages
• Support for Plutus V4
• Key language features: namespaces, built-in test support, comprehensive standard library
• Documentation and tutorials for onboarding new developers

Estimated Effort

2 FTEs

Developer Tooling

Goal

Provide a complete development experience for Pebble developers with IDE integration, debugging tools, and build system support.

Key Results

• Language Server Protocol (LSP) implementation:
• Syntax highlighting
• Auto-completion
• Go-to-definition
• Find references
• Inline error reporting
• Hover documentation
• Stable and reliable sourcemaps for debugging compiled contracts
• CLI improvements:
• Build and watch modes
• REPL for interactive development
• Blueprint generation for contract metadata

Estimated Effort

1.5 FTEs

Pebble Summary

• total resources estimated: 3.5 FTEs

Differentiation from Aiken

Pebble and Aiken serve different developer profiles and are complementary within the Cardano ecosystem, not competitive.

Why both matter

Cardano needs multiple on-ramps for developers:
- Developers with Rust/Haskell/FP experience gravitate toward Aiken
- Developers with JS/TS/Solidity experience will find Pebble more accessible
- Both compile to optimized UPLC; the choice is about developer preference, not runtime performance

By funding Pebble, the Treasury expands Cardano's developer funnel without fragmenting it.

Hard-fork maintenance

Upcoming Intra-Era Hard Fork

Goal

Ensure all HLabs TypeScript libraries are updated and fully compatible with the upcoming hard fork, including Plutus V4 changes and new protocol parameters.

Key Results

Maintenance of the affected repositories to support new protocol features:

• cardano-ledger-ts: Collection of functions and classes defining the Cardano ledger data structures
• ouroboros-miniprotocols-ts: TypeScript implementation of the Ouroboros networking protocol
• plutus-machine: CEK machine implementation for UPLC evaluation
• uplc: TypeScript/JavaScript representation of UPLC

Estimated Effort

1.5 FTE

Hard-Fork Maintenance Summary

• total resources estimated: 1.5 FTE