Stellar

Agentic and machine-to-machine payments on Stellar. Covers x402 (HTTP 402 paid APIs via OZ Channels facilitator, fee-sponsored clients) and MPP (Machine Payments Protocol) in both Charge mode (per-request Soroban SAC) and Channel mode (off-chain commits, high-frequency). Defaults to USDC (SEP-41 SAC) on `stellar:testnet`/`stellar:pubnet` (CAIP-2). Use when selling a paid API to AI agents, building an x402 client, or designing a payment-channel architecture for high-frequency agent traffic.

Soroban smart contract development on Stellar (Rust SDK). Covers project setup, contract structure, storage types, authorization, cross-contract calls, events, error handling, testing (unit, integration, fuzz, property, mutation, fork, differential), security patterns and vulnerability classes, advanced architecture patterns (upgrades, factories, governance, DeFi primitives), and common pitfalls. Use when writing, testing, securing, or shipping Soroban contracts.

Stellar dApp / frontend development. Covers the JavaScript stellar-sdk (browser + Node.js), Freighter wallet, Stellar Wallets Kit (multi-wallet), Wallet Standard, smart accounts with passkeys, transaction building / signing / submission, Soroban contract invocation from the client, simulation, and error handling. Use when building a React/Next.js/Node.js app that talks to Stellar or Soroban.

Stellar standards, ecosystem, and reference. Covers SEPs (Stellar Ecosystem Proposals), CAPs (Core Advancement Proposals), and a quick map for picking the right standard for wallets, anchors, payments, deposits/withdrawals, federation, deep links, and KYC. Also bundles ecosystem references (DeFi protocols, dev tools, wallets, infra, community projects) and curated documentation links. Use when you need to know which SEP applies, or want a starting point for ecosystem integrations and official docs.

Querying Stellar chain data via Stellar RPC (preferred) and Horizon (legacy). Covers RPC JSON-RPC methods, Horizon REST endpoints, streaming, pagination, historical queries, Hubble/Galexie for deep history, and the RPC/Horizon migration story. Use when reading balances, transactions, operations, ledgers, contract events, or building any indexer/analytics workflow.

Stellar Assets (classic) + trustlines + Stellar Asset Contract (SAC) bridge to Soroban. Covers asset issuance, distribution, authorization flags, clawback, regulated assets, trustline management, and the SAC interop layer that exposes classic assets as Soroban tokens. Use when tokenizing real-world assets, issuing stablecoins, managing trustlines, or bridging classic assets to Soroban contracts.

Zero-knowledge cryptography and privacy patterns on Stellar/Soroban. Covers Groth16 verification, BLS12-381 (CAP-0059, available), BN254 + Poseidon host functions (CAP-0074/0075, status-sensitive), Noir / RISC Zero integration, privacy pools, confidential tokens, Merkle tree commitments, and status-sensitive guidance for protocol/SDK readiness. Use when building privacy-preserving applications or ZK-verifier contracts on Stellar.