Coinholder-Directed Retroactive Grants Program Q2 2026 - 30 Day Review Period Now Open (Postponed to Q3)

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 June 17th at 20:00 UTC 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 as well as external resources. Please visit the GitHub links for full details.

List:

Project Name: Zcash Grants Hub

Organization: Daniel Goh

Request: $3,050 USD

Github: Link

Synopsis:

Zcash Grants Hub built and shipped an open-source unified grants platform aggregating ZCG, Coinholder Grants, and ZecHub DAO proposals into a single interface, with filtering/sorting, grant detail pages, analytics views, GitHub-based submission UX improvements, and ZecHub DAO participation guidance — completed in April 2026.

Evidence: (see GH link for full context)

Project Name: Expanding Zcash In Unstoppable Wallet

Organization: Horizontal Systems - Unstoppable Wallet

Request: $50,000 USD

Github: Link

Synopsis:

Unstoppable Wallet submits a retroactive grant for Q1–Q2 2026 work expanding Zcash swap infrastructure — adding DEX/RFQ liquidity sources (NEAR Intents, Maya Protocol, LetsExchange, StealthEX, and others), a provider risk classification system, multi-channel swap access (mobile, web, Telegram bot), and Zcash-specific improvements including faster sync, shielded address rotation, and birthday height/rescan tooling.

Evidence: (see GH link for full context)

Project Name: Open-Source Zcash Hardware-Wallet SDK

Organization: wh00hw (solo developer)

Request: $40,000 USD

Github: Link

Synopsis:

An independent developer (wh00hw) submits a retroactive grant for building the first portable, vendor-neutral, plain-C Orchard hardware wallet stack (~20,300 LOC across four MIT-licensed repos): a C11 cryptographic library (libzcash-orchard-c), a Rust signing SDK (zcash-hw-wallet-sdk), a Flipper Zero application (FlipZcash), and an ESP32-S2 reference port — culminating in the first Orchard-shielded spend ever signed offline by a Flipper Zero, broadcast on mainnet 2026-03-30.

Evidence: (see GH link for full context)

  • Repository/Commit:

    • libzcash-orchard-c - HEAD commit (at time of submission): 0107c79 “enforce empty Sapling bundle on TxMeta (Orchard-only invariant)” (2026-05-01). Recent commits include the Sapling-component lockout at 0107c79, the test-vector hardening at 1ff2f69 and 1562373 (replace strcpy+strcat with snprintf in sinsemilla_short_commit, 2026-04-30); the on-device sighash-verification milestone is at de08d13 (2026-04-16). The full 49 KAT cross-check against librustzcash plus the four-test signer suite (sapling empty accepted, non-empty rejected, single bit-flip rejected, constant deterministic) passes on a fresh build at this HEAD (see Section 5 — Verification for the reproducible command). LICENSE: MIT. Key files: src/pallas.c, src/orchard.c, src/redpallas.c, src/zip244.c, src/orchard_signer.c, src/hwp.c, SECURITY.md, tests/test_vectors.c

    • zcash-hw-wallet-sdk - HEAD commit (at time of submission): f10a80a “reject Sapling-bearing PCZTs before transmission (Orchard-only)” (2026-05-01); the prior on-device-sighash-verification milestone is at bbef269 (2026-04-30). LICENSE: MIT OR Apache-2.0. Key files: src/workflow.rs, src/protocol/hwp.rs, src/traits.rs, src/verify.rs, tests/integration.rs

    • FlipZcash - HEAD commit (current main): 1adc84f “fix CI build: replace strcat with snprintf and bump libzcash submodule” (2026-04-30). The earlier README-update milestone is at HEAD~1 (e81d674, 2026-04-23). LICENSE: MIT (file at repo root; cryptographic submodule lib/libzcash-orchard-c/ is separately MIT). Key evidence (in repo): screenshots/mainnet_broadcast.png, screenshots/mainnet_pair.png, screenshots/memo.png; mainnet tx 1c9eb6ca4ada67bf66452120d128ceacf2c0e21146de089e51694eb14db5466b (wallet birthday block 3,290,915, broadcast 2026-03-30) recorded in README.md; complete technical documentation in IMPLEMENTATION.md (architecture, primitives, derivation pipeline, HWP wire protocol, on-device sighash verification state machine, performance, security model, standards conformance).

    • zcash-hw-wallet-esp32 - HEAD commit (at time of submission): 488222a “update README” (2026-05-01); the substantive Sapling-component-lockout firmware change (libzcash submodule pointer bump to 0107c79, HWP_ERR_SAPLING_NOT_EMPTY mapping, wallet_get_seed exposure for the transparent ECDSA path, and bip32.c / secp256k1.c linkage in the component CMakeLists) is at HEAD~1 (d21206c “enforce Sapling empty-bundle invariant + wire transparent ECDSA path”, 2026-05-01); the prior on-device sighash-verification milestone is at 2d5258c (2026-04-30); the network-discrimination milestone is at 33b9fc8 (2026-04-10). LICENSE: MIT (declared in README.md; license text is shipped via the libzcash-orchard-c submodule). Key files: main/main.c, main/wallet.c, main/usb_transport.c, main/led_status.c

    • Prototype integration on a personal fork of the third-party zipher-cli (not part of the retroactive LOC count; listed only as engineering evidence that the SDK is adoptable by a third-party wallet shape with minimal glue) - The applicant’s commits touching rust/crates/cli/ and rust/crates/engine/src/hw_signer.rs implement a hw pair subcommand, a send confirm-hw subcommand, and transport selection for Ledger / Speculos / serial. The fork has not been merged upstream into atmospherelabs-dev/zipher-app, so it must not be read as third-party adoption.

Project Name: Zafu Browser Extension

Organization: Rotko Networks OU

Request: $38,000 USD

Github: Link

Synopsis:

Zafu (Rotko Networks) submits a retroactive grant for a privacy-centric Chrome MV3 browser wallet built around Zcash (with Penumbra as a second supported chain), delivering sub-12-second client-side Halo2 proving via parallelized WASM, end-to-end FROST t-of-n Orchard multisig, a QR-only air-gapped signer (Zigner), and a per-site identity SDK (ZID) — published as an open-source beta on the Chrome Web Store.

Evidence: (see GH link for full context)

Project Name: CipherPay

Organization: Atmosphere Labs (Kenbak)

Request: $35,000 USD

Github: Link

Synopsis:

CipherPay (Atmosphere Labs) submits a retroactive grant for a non-custodial Zcash commerce platform built February–May 2026, shipping six MIT-licensed repositories covering payment processing, subscriptions, e-commerce plugins (Shopify, WooCommerce), event ticketing, AI agent payments (x402, MCP), and a point-of-sale interface — live at cipherpay.app with real merchants and a documented humanitarian use case.

Evidence: (see GH link for full context)

Repository/Commit:

  • CipherPay API — Rust backend, MIT license. First commit 76f9da7 (2026-02-21). Payment processor core with Orchard trial decryption, subscription engine, billing, events, x402 facilitator, agent sessions, restricted API keys.

  • CipherPay Web — Next.js frontend, MIT license. First commit b3ee67f (2026-02-21). Merchant dashboard, hosted checkout, documentation, landing page, donation campaign UI.

  • CipherPay for Shopify — Shopify app bridge, MIT license. OAuth, payment sessions, checkout UI extension, webhook bridge.

  • CipherPay for WooCommerce — WooCommerce payment gateway, GPLv2 license. Block checkout support, HMAC webhooks.

  • CipherPay x402 — HTTP 402 middleware, MIT license. x402 v2, MPP, prepaid sessions, /.well-known/payment discovery.

  • CipherPay MCP — MCP server for AI agents, MIT license. 8 tools, 2 resources.

Publication:

Deployment/Release:

Project Name: ZAP1

Organization: Frontier Compute

Request: $28,000 USD

Github: Link

Synopsis:

ZAP1 (Frontier Compute) submits a retroactive grant for a Zcash application-layer attestation protocol built March–May 2026, using BLAKE2b Merkle commitments anchored to mainnet via Orchard shielded memos, with a Rust reference implementation, standalone verification crate, JavaScript/NPM package, and live public API — designed to let applications prove lifecycle event completion without exposing private data.

Evidence: (see GH link for full context)

Project Name: THORSwap/Metro

Organization: THORSwap Labs

Request: $60,000 USD

Github: Link

Synopsis:

THORSwap submits a retroactive grant for integrating native ZEC cross-chain swaps into THORSwap and Metro wallet (launched October 2025), reporting $50M+ in ZEC volume, a $520K largest single swap, 24+ supported chains, and dual routing via Maya Protocol and NEAR Intents — with no KYC, no custody, and hardware wallet support.

Evidence: (see GH link for full context)

Project Name: ZODL Q1 2026 Core Protocol Development

Organization: ZODL

Request: $818,438 USD

Github: Link

Synopsis:

Zcash Open Development Lab (ZODL) requests retroactive reimbursement for Q1 2026 core protocol work, covering librustzcash maintenance (11 crate releases), Android/iOS SDK releases, Zallet alpha.4 progress, ZIP authoring/review (ZIP 316 Rev 2, ZIP 231, ZIP 2005), post-quantum R&D, and — critically — the patch and coordinated disclosure for the zcashd Sprout pool verification vulnerability (zcashd v6.12.0, March 31). Mobile wallet development is explicitly excluded, funded separately by in-app swap fees.

Evidence: (see GH link for full context)

Weekly progress updates (Q1 2026):

Repositories (all open-source):

Tagged releases shipped in Q1 2026:

Key merged PRs / shipped specs and supporting issues (grouped by repository):

ZIPs (zcash/zips):

  • #1206 — ZIP 316 Revision 2 (merged).

  • #1191 — ZIP 231 audit response, abstract/motivation clarifications (merged).

  • #1192 — ZIP 231 Defuse Security audit response (merged).

  • #1214 — ZIP 48 OVK derivation scheme (draft, circulated for community review).

  • #1156 — ZIP 248 extensible transaction format (open, ongoing editor work).

  • #1207 — ZIP 2005 Orchard Quantum Recoverability (open).

  • #1198 — PIR for nullifier exclusion proofs (review).

  • #1220 — ZIP 316 key-origin-info follow-on issue.

Rust libraries (zcash/librustzcash):

  • #2179 — PCZT generalization.

  • #2147 — block-height-bounded chain truncation (truncate_to_chain_state).

  • #2248 — truncate_to_chain_state hardening.

  • #1781 — CompactBlock transparent data.

  • #2036 — low-level transparent data API.

  • #2194 — standalone P2SH address import.

  • #1917 — EIP-681 parser.

  • #2134 — EIP-681 high-level API.

  • #2120 — EIP-681 case-sensitivity fix.

  • #2133 — EIP-681 uint256 fix.

  • #2165 — EIP-681 TransactionRequest::from_parts fix.

  • #2191 — zip321::Payment::new returns Result.

  • #2235 — zip321 proptest filter.

  • #2236 — #![deny(missing_docs)] on zcash_client_sqlite.

  • #2137 — sync-engine unification of compact-block and full-tx pathways (blocking Zallet alpha.4).

  • #2250 — full-block scanning (blocking Zallet alpha.4).

Zallet (zcash/wallet):

  • #362 — z_getbalances multi-account balance RPC (str4d).

  • #288 — Zallet alpha.4 tracking issue.

zcashd (zcash/zcash):

  • #7039 — removal of legacy P2P alert handling (centralization reduction); shipped in v6.12.0 alongside the coordinated Sprout-pool-verification fix.

Integration tests (zcash/integration-tests):

  • #1 — RPC framework migration from zcashd.

  • #2 — CI independence from zcashd.

  • #52 — replacing zcashd book content with integration-testing documentation.

Android SDK (zcash/zcash-android-wallet-sdk):

  • #1888 — rewindToChainState handler.

  • #1900 — Synchronizer.rescanFromHeight API.

  • #1901 — TypesafeBackend.rewindToChainState wired into importAccountByUfvk.

  • #1907 — deleteAccount FFI method.

  • #1879 — shardtree note-commitment-tree integration.

Swift SDK (zcash/zcash-swift-wallet-sdk):

  • #1636 — iOS SDK/FFI reunification.

  • #1651 — FFI reunification follow-up.

  • #1652 — FFI reunification follow-up.

  • #1649 — broadcast-target correctness fix.

  • #1642 — Sapling/Orchard subtree-roots fix.

  • #1633 — Tor submit-API error handling.

  • #1654 — Swift SDK rewind-to-chain-state (merged 2026-04-20, Q2 work; referenced here for context).

Public presentations:

  • Orchard Quantum Recoverability — Daira-Emma at Zcash Engineering Office Hours: https://www.youtube.com/watch?v=R6916H2IMKI

  • High Assurance Cryptography Symposium and Real World Crypto, Taipei, March 2026 — team participation contributing to Zcash’s post-quantum direction.

Project Name: ZcashNames

Organization: ZcashMe, Inc.

Request: $122,400 USD

Github: Link

Synopsis:

ZcashNames submits a retroactive grant for building an on-chain Zcash naming system (ZNS) mapping human-readable names like alice.zcash to shielded addresses, delivered as a live beta web app, public explorer, docs portal, and developer SDK — framed as the trust-minimized successor to their prior centralized product, ZcashMe.

Evidence: (see GH link for full context)

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Update: Q2 2026 Coinholder Retroactive Grants Vote Postponed to Q3

FPF, in coordination with the Valar Group, has decided to postpone the coinholder poll for the Q2 2026 Retroactive Grants Program to Q3 2026.

The coinholder voting protocol relies on Orchard notes to determine voting power. In light of the recently disclosed Orchard vulnerability, we do not believe it is appropriate to conduct a coinholder vote at this time.

Any vote held today could face questions about whether voting power accurately reflected coinholder ownership at the time of the snapshot. Regardless of the ultimate conclusions reached regarding the impact of the issue, we want grant-funding decisions to be determined through a process that the community can have confidence in and that applicants are not placed in a position where the legitimacy of the results is later called into question.

For applicants: your submission can remain as-is and carry forward to the Q3 vote, or you may withdraw it, revise it, and resubmit. The choice is yours: please indicate your preference in your grant thread.

We will share the Q3 timeline once it has been finalized. Thank you for your patience and understanding.

-– FPF

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