codex

Colosseum Codex: Solana Handbook, BitcoinKit, DFlow JIT Router

Solana Handbook, BitcoinKit, DFlow JIT Router, Phantom Cash, Wallet UI v2

Mike Hale

03 Oct 2025 — 4 min read

Here's what's featured in this week's issue:

Ackee has open-sourced their School of Solana Handbook
Zeus Network launches BitcoinKit for BTC powered DeFi apps on Solana
DFlow launches JIT Router to optimize trades during transaction execution
Phantom Announces Phantom Cash and CASH Stablecoin for consumer payments
Wallet UI v2 ships a new, modular approach

👩‍🏫 Solana Handbook

Ackee has open-sourced their School of Solana Handbook, written by active auditors, with actionable knowledge for builders.

Modules cover fundamentals to advanced program architecture:

Solana Basics: Learn the foundations of the blockchain
Core Concepts: The eight unique features that make Solana fast
Programming Model: How to build with Solana’s parallel runtime
Solana Program Library: Ready-made programs for tokens, accounts, and more

This is the same battle-tested curriculum used in the School of Solana program and auditor training, now free for all builders

Solana Handbook

🪙 BitcoinKit

Zeus Network has introduced BitcoinKit, an open-source infrastructure toolkit that transforms Bitcoin into programmable money on Solana. The goal is to give developers direct, permissionless access to Bitcoin’s $2T liquidity without relying on custodians, wrapped tokens, or fragmented L2 solutions.

BitcoinKit leverages ZeusLayer to verify and tokenize BTC deposits in real time, creating zBTC, a token backed 1:1 by native Bitcoin.

Once issued, zBTC can flow seamlessly into Solana DeFi protocols, where it behaves like any other onchain asset while retaining Bitcoin’s underlying security guarantees.

BitcoinKit is designed with a developer-first approach, offering multiple integration paths including widgets, agents, CLI tools, APIs, and full SDKs.

BitcoinKit debuts inside Jupnet (Jupiter’s Omnichain Liquidity Network), enabling users to deposit and withdraw native BTC directly into Solana.

This gives developers the ability to build Bitcoin-backed lending markets, BTC-stablecoin swaps,or yield products, all powered by Solana’s high-throughput runtime.

BitcoinKit: The Open Infrastructure Kit Unlocking Bitcoin's Programmable Economy

🛣️ DFlow JIT Router

DFlow has relaunched with a rebuilt aggregator, new interface, and a new Just in Time routing engine that can optimize a swap during transaction execution, not only before it.

Traditional aggregators calculate routes offchain, locking them in before a transaction is executed, often leading to failed swaps or heavy slippage.

DFlow’s JIT Router solves this by checking market prices at the moment of execution.

If conditions have shifted, it automatically reroutes to the best venue all within the same transaction.

Swap instructions can branch dynamically, letting the router select the optimal liquidity source in real time so traders capture the best price on swaps.

Developers can leverage JIT Routing to offer users the best swaps in their own apps, focusing on product innovation while DFlow ensures trades settle efficiently under the hood.

The DFlow JIT Router: Bringing Routing Intelligence Onchain

💳 Phantom Cash

Phantom has launched Phantom Cash, a new consumer payments platform that expands its Solana wallet into a full money app.

Powered by $CASH, a USD-pegged stablecoin issued via Bridge (Stripe’s Open Issuance infrastructure), Phantom Cash lets users add money via bank or card directly in-app, buy/sell stablecoins with no fees, and spend anywhere Visa is accepted through Apple Pay, Google Pay, or a Phantom debit card.

Launching exclusively on Solana (initially), Phantom Cash signals the wallet’s shift from a crypto-first product to a mainstream consumer payments app, giving its 15M monthly users an easy way to spend, send, and save with stablecoins.

Builders can integrate CASH into DeFi protocols, payments apps, and consumer products and a path to connect payments and stablecoin DeFi in one ecosystem.

Introducing Phantom Cash: New Money, Now in Your Wallet

👛 Wallet UI v2

Wallet UI v2 is a major update that makes the developer toolkit leaner, and more reliable.

The release includes:

Comprehensive new docs with examples
Fixes for functional and logical errors that broke apps or caused odd behavior
Separation of Gill SDK into its own package, allowing cleaner composition with any client
Improved stability and flexibility

This modular shift means devs can now plug Wallet UI into different backends, creating a clean upgrade path to modern SDKs.

Wallet UI

⚡ Quick Hits

How to CRUSH the Colosseum Hackathon Cypherpunk! - @SuperteamFRANCE

Kite is out with full Solana Kit 3 support - @SolanaKite

Build a Low-Latency Solana Event Tracker with LYS Labs on QuickNode - QuickNode

Solana Hackathon Playbook With Surfpool (video) - @Alexspoof

MagicBlock Real-Time Cypherpunk Hackathon Side Track - MagicBlock

Squads $100k Grid Grant Program - @SquadsProtocol

Dev.fun On-Chain App Jam winners - @devfunpump

List of helpful links for Colosseum Cypherpunk Hackathon teams - @SaigonButcher

Introducing Keel: Solana's Capital Engine - @keel_fi

⚙️ Tools & Resources

samui-wallet is an open source Solana wallet with the tools developers need for protocol testing, integration, and experimentation

Yellowstone Vixen v0.5.0 introduces customizable sources, letting developers stream from gRPC, RPC, snapshots, or Fumarole, all through the same parser pipeline.

pinocchio-stake-program is a developer-friendly test build of Solana’s Stake program, designed to mimic the real thing so you can run, validate, and test stake flows

account_socket is a lightweight WebSocket server that monitors programs in real time, caching data with SQLite/Redis and streaming updates without the overhead of running Geyser.

clmm-rust is a Concentrated Liquidity Market Maker implementation in pure Rust for Solana

💸 Funding

Share has raised $5M from Coinbase Ventures, Collab+Currency, Palm Tree Crypto, and others to build a social trading app that indexes transactions across Solana, Base, and Ethereum, with funds going toward expanding its cross-chain data feeds, trading features, and social user experience.

👩‍🔧 Get Hired

Helium is hiring a Senior DevOps Engineer
Codigo is hiring a Solana Developer
Everstake is hiring a Senior Technical Content Specialist
Anza is hiring a Senior Engineer, Cryptography

🎧 Listen to This

Decentralized Voices

In this episode, Daria sits down with Vadym Nesterenko (DeFi researcher, product manager, and investor) to unpack the realities of building in crypto.

They cover the hardest challenges of launching crypto products, how to measure success with the right DeFi product metrics, and ways to balance organic growth vs. heavy incentives when solving the cold-start problem.

Vadym also shares insights on building for long-term value over short-term hype, the best entry points for new onchain products, and why product managers often stay behind the scenes.

Crypto Product Manager’s Playbook: Crucial Metrics, UX, and Community Growth

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