Review Period Open - Coinholder-Directed Grants Program Q1 2026

Community Grants Retroactive Grants
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Now that the submission deadline has passed, the mandatory 30-day review period has begun. During this time, please review the submitted proposals and engage with the applicants in their individual grant threads. This is your opportunity to ask questions, share constructive feedback, test out the evidence provided for completed work and raise any concerns. The review period will end on March 17th and will be followed by a coinholder poll.

Below you will find a summary of each grant request with links to their individual grant threads (in the project name) as well as external resources. Grants are presented from least USD requested to most. Please visit the GitHub links for full details.

Project Name: ZChat - The First Working Zcash-Native Private Messenger

Organization: ZChat Privacy Technologies (Liberland)

Request: $5,000

Github: Link

Synopsis:

ZChat is a fully delivered, Zcash-native private messaging application that uses shielded Zcash transactions as its transport layer, making every message an on-chain transaction with an encrypted memo and requiring no phone number, email, accounts, or KYC—only a Zcash address. Built independently from scratch, the project introduces the ZMSG Protocol (v4), enabling rich features such as direct and group messaging, payment requests, reactions, replies, read receipts, and long messages via secure chunking, all within existing Zcash memo constraints and without reliance on future protocol upgrades. The delivered system includes a stable Android app with a self-custody wallet, group key management and rotation, production-grade cryptography (HKDF, authenticated key exchange, and ECIES with forward secrecy), and a lightweight web client for testing. As the only functioning Zcash messenger on mainnet today, ZChat demonstrates a novel, real-world use case for Zcash beyond payments and contributes tangible, independently built infrastructure to the ecosystem.

Evidence: (see GH link for full context)

Repository/Commit:

GitHub Repository - Full source code for ZChat Android app, web interface, and ZMSG protocol implementation

Publication:

  • Zcash Community Forum Thread - Grant application thread with January 2026 development update, community discussion, and technical details

  • Previous ZCG Application — Issue #142 - Original grant application documenting project scope and goals

    Deployment/Release:

  • zsend.xyz - Live web demo — working Zcash messenger, try it now

  • Android APK v2.8.1 available for download from GitHub releases or by whitelist request on zsend.xyz

    Other Evidence:

  • Zypherpunk Hackathon 2025 — prize winner ($600 awarded), results publicly verifiable

  • January 2026 Forum Update - Detailed technical progress post with security hardening documentation

Project Name: Zec-pay.com

Organization: Tomas Matejicek

Request: $22,600

Github: Link

Synopsis:

zec-pay.com is a web-based payment service that enables anyone to fund a transaction with BTC or transparent ZEC while the recipient receives shielded ZEC with an attached memo, supporting common use cases such as invoices, donations, and order references. The platform lowers barriers for users of transparent-only and hardware wallets by abstracting shielded transaction creation and memo handling, ensuring that final settlement occurs privately on Zcash. The system combines a frontend order interface with a backend state machine that generates unique deposit addresses, monitors Bitcoin and Zcash nodes for confirmed payments, executes BTC–ZEC swaps via the CoinEx API when required, and broadcasts shielded Zcash transactions from a managed hot wallet. It includes rebalancing between exchange and local liquidity, refund tooling, an admin dashboard, and hardened deployment infrastructure, and has been iteratively improved through public user feedback to enhance validation, clarity, and reliability.

Evidence: (see GH link for full context)

Project Name: Maya Protocol Advanced Shielded ZEC Support

Organization: Maya Protocol

Request: $45,000

Github: Link

Forum Discussion: Link

Synopsis:

Maya Protocol has independently built and deployed full end-to-end support for shielded Zcash (ZEC) on its cross-chain decentralized exchange, becoming the first and only permissionless DEX to enable native cross-chain swaps directly to and from shielded Sapling and Orchard addresses without intermediaries, KYC, or custodians. Forked from THORChain, Maya Protocol extends beyond prior grant-funded concepts to deliver production-grade functionality, including shielded inbound and outbound transactions, memo parsing via trial decryption, Unified Address normalization, expanded memo limits, robust ZEC UTXO management, NU6/NU6.1 upgrade support, and a custom Rust-to-Go FFI layer exposing shielded cryptography to its Go-based client. This retroactive grant application covers substantial uncompensated engineering work that gives Zcash users unprecedented access to cross-chain liquidity while preserving financial privacy, directly advancing Zcash’s ecosystem and mission.

Evidence: (see GH link for full context)

Project Name: ZChat - ZK Email in Halo2

Organization: ZK Email

Request: $50,000

Github: Link

Synopsis:

ZK Email is an open-source initiative focused on making zero-knowledge (ZK) cryptography more practical and user-friendly by developing core primitives and tooling within the halo2 ecosystem. The project’s halo2-zk-email suite provides reusable circuits that enable zero-knowledge verification of DKIM-signed emails, allowing selective proof of properties such as sender, subject, or content without revealing the full message. To achieve this, the team built modular libraries—including halo2-rsa for big-integer arithmetic and RSA verification, halo2-regex for DFA-based regex matching, halo2-base64 for encoding/decoding, and an optimized SHA256 for arbitrary-length inputs—on top of Axiom’s halo2-lib and the PSE halo2 fork. Designed as MIT-licensed public goods, these components are independently reusable and have already been adopted by multiple projects. The system architecture emphasizes scalability and deployability, using lookup-optimized range checks, universal verifier patterns, contract splitting to meet EVM size constraints, and recursive proof design suitable for efficient on-chain verification, while advancing developer tooling and foundational ZK infrastructure.

Evidence: (see GH link for full context)

Project Name: Zcash.me

Organization: ZcashMe, Inc.

Request: $61,200

Github: Link

Synopsis:

Zcash.me is a user-friendly identity and payments platform designed to simplify peer-to-peer transactions in Zcash by replacing complex addresses with human-readable profile pages and shareable links. The application enables users to create verified public profiles, accept payments via QR or wallet URI, denominate amounts in fiat with live conversion to ZEC, and receive ZEC even when senders initiate payments from other crypto assets through integrated cross-chain swap flows. It also provides searchable discovery of recipients by username or social handle, wallet API integrations for richer directory experiences, and verification mechanisms using memo + OTP and social authentication to confirm address ownership and identity. Built as a modular Next.js web application with a Postgres database, Supabase OAuth, external pricing oracles, and a dedicated background verification service leveraging Zcashd RPC and librustzcash, the project emphasizes secure authentication, scalable verification infrastructure, and practical usability features such as directories, referrals, and point-of-sale tooling to advance real-world peer-to-peer electronic cash adoption.

Evidence: (see GH link for full context)

Project Name: Pepper-Sync

Organization: Zingo Labs

Request: $461,000

Github: Link

Synopsis:

In response to slow synchronization being a major usability barrier to Zcash adoption in late 2024, Zingo Labs designed and deployed Pepper-Sync, a novel client-side synchronization implementation that achieves competitive raw performance and, at the time of release, enabled the fastest spend-before-full-sync experience in production. The project addresses the inherent “syncing problem” in private transactions—where resource-constrained devices must perform large volumes of trial decryption—by combining DAG-inspired techniques, incremental Merkle tree pruning, nullifier lookup for non-linear receipt tracking, and prioritized multithreaded scanning built on librustzcash primitives. This approach reduces unnecessary computation while preserving full privacy guarantees, enabling efficient detection of relevant notes and faster access to funds, especially for mobile users. Beyond the core algorithm, the team integrated Pepper-Sync into Zingo PC and Zingo Mobile alongside protocol upgrades (NU6/6.1, ZIP 317, ZIP 320), UX improvements, multilingual support, Tor opt-in, and broader accessibility features, ensuring real end-user impact. Complementary outreach, documentation, and support efforts expanded adoption and awareness, contributing to measurable download growth and a positive ecosystem effect by motivating improvements among other sync providers.

Evidence: (see GH link for full context)

  • The algorithm is already deployed in four Zingo Labs applications:
    zingo-cli, zingo-pc, zexcavator, and zingo-mobile.

  • Repository/Commit: Pepper-Sync – the core library

  • Deployment/Release: zexcavator – Community ZEC Recovery Tool

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One question: Project Name: [ZChat - ZK Email in Halo2]

I suppose that the full name of the project #4 not include “Zchat” in the name?

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ZChat (Liberland): support.

Zec-pay.com: This seems to me to basically defeat the point of Zcash’s shielded features. It just is not difficult to use a wallet that directly supports shielded transactions. The BTC-to-ZEC functionality is a little more useful, but the website appears to be acting as a money transmitter (because it has temporary custody of the funds sent to it), while saying that it “never asks for sign-ups or KYC”. It doesn’t appear to have attracted regulatory attention but it easily could.

Maya Protocol Advanced Shielded ZEC Support: as I said here, I strongly support this grant.

ZK Email in Halo 2 (not sure why “ZChat” is also in the title): The paper is very short and I would have appreciated more detail. I am skeptical of the security assumptions: DKIM is not really designed to authorize monetary transfers.

Zcash.me: I’m generally very skeptical about this kind of centralized platform. What stops this becoming another Lavabit?

Pepper-Sync: This is a pretty expensive grant. Also wasn’t ZExCavator supposed to already be covered by another grant? Grant Application - Zcash Extensible Wallet Interchange Format (ZeWiF) · Issue #3 · ZcashCommunityGrants/zcashcommunitygrants · GitHub says:

Blockchain Commons and Zingo Labs will: collect and survey existing wallets (a wide-ranging survey, with a focus on zcashd and zecwallet); design an interoperable and extensible wallet interchange format that can preserve and secure data from zcashd and other wallets including legacy zecwallets; create Rust crates that import data into and export data from that interchange format; and produce a ZExCavator tool that recovers buried ZEC from old zecwallets.

I think ZExCavator cannot be cited as contributing to the scope of this grant, because the ZeWIF grant was supposed to fully pay for Zingo Labs’ part in its development (see deliverable #4.1). @hanh also points out other potential coverage duplication here.

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Application for Retroactive Funding for Pepper-Sync (second attempt)
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You’re correct, I updated our thread to clarify that the portion of ZExCavator we were requesting funding for is subsequent to the referenced ZeWIF grant, and in flight but as it’s not complete is not yet suitable for retroactive funding.

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@daira Thank you for your feedback :slight_smile:

I fully agree that zec-pay.com is not end-to-end private in the way Zcash shielded transactions are, because the service can see the memo during processing. The intended use is cases where that is not a problem, such as memos that are already encrypted by the sender, or memos that are inherently non-sensitive metadata (invoice/order IDs, donation notes, etc.).

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Thank you for the thoughtful question! :slight_smile:

As I understand it, Lavabit operated as a centralized service that received, stored and delivered user’s private messages. That created a single point where data could be compelled or seized.

ZcashMe cannot act as a middleman in this way because the app does not send or receive messages or money, and it does not hold them or even see them.

For transactions the user is provided ZIP321 URI that they can complete in their wallet. The application only supports shielded addresses and does not accept transparent addresses.

We recognize that metadata risks still exist at the network level. For example, visiting someone’s profile suggests that you may have interacted with them. Users who want stronger protections can choose to access the site with Tor or Nym to reduce IP and traffic metadata.

All information collected is limited to what users have chosen to make public, like their display name, bio, social media links, and the receiving address they want others to use.

In an upcoming release, users will be able to verify that their profile data was not altered by anyone else.

We expect others have similar concerns so we will make these points clear on our homepage.

Are there any concerns we failed to address?

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