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By Wirex - Vottun Stellar SDK: A Scalable Development Framework
The project delivers a modular, ecosystem-reusable SDK for the Stellar blockchain, designed to simplify the development of payment-enabled applications and accelerate real-world adoption of Stellar.
1. Wallet Management Module
Stellar usage:
Integrates directly with Horizon APIs to manage Stellar accounts, balances, trustlines, and issued assets (XLM, USDC, EURC). All key handling and signing remain client-side to support non-custodial architectures.
Impact:
Reduces the complexity of building secure, non-custodial wallets on Stellar and provides a consistent foundation for asset management across applications.
2. Transaction Lifecycle Module
Stellar usage:
Abstracts Stellar transaction construction, signing, fee handling, submission, and monitoring via Horizon.
Impact:
Eliminates boilerplate transaction logic, reduces integration errors, and enables developers to reliably submit and track Stellar transactions in production environments.
3. Smart Contract Interaction Module (Soroban)
Stellar usage:
Provides high-level abstractions for interacting with Soroban smart contracts, including invocation, parameter encoding, and result decoding.
Impact:
Lowers the barrier for developers to integrate smart contract functionality into Stellar applications and encourages adoption of Soroban in real-world use cases.
4. API Client Module
Stellar usage:
Unifies access to Stellar network APIs and external services through standardized request/response and error handling models.
Impact:
Enables clean, maintainable integrations between Stellar applications and off-chain services, improving developer productivity and integration quality.
5. WebSocket & Streaming Module
Stellar usage:
Leverages Horizon streaming endpoints to provide real-time updates for accounts, transactions, and network events.
Impact:
Allows applications to react instantly to on-chain activity, enabling responsive user experiences and real-time payment flows.
6. Configuration Module
Stellar usage:
Manages testnet and mainnet environments, network parameters, and deployment configuration.
Impact:
Ensures deterministic behavior across environments and simplifies the path from development to mainnet deployment.
7. Reference Integration: Wirex Payments
Stellar usage:
Demonstrates how regulated payment and settlement flows can be connected to Stellar using on-chain settlement with XLM, USDC, and EURC.
Impact:
Serves as a reusable example for the ecosystem, enabling developers to build real-world payment and card-enabled applications on Stellar without compromising non-custodial design.
$129.6K
Wirex is a mature, production-grade fintech infrastructure provider with significant real-world traction and a long operating history. Founded in 2014, Wirex serves 7+ million users globally, has processed $20+ billion in transaction volume, operates across 130+ countries, and has received 20+ industry awards for its payments and crypto infrastructure products .
Wirex Banking-as-a-Service (BaaS) is already live and operating at scale, providing self-custodial card issuance, IBAN accounts, and stablecoin settlement rails to fintechs and Web3-native companies. As a principal member of both Visa and Mastercard, Wirex enables card acceptance at 80+ million merchants worldwide across 200+ countries .
The platform currently supports 18 active BaaS clients, including leading Web3 and fintech players such as LOBSTR (the most trusted Stellar wallet), Simple.App, Best Wallet, Folks Finance, the Cardano Foundation, FC Barcelona (Barça Mobile), and FreedX . Several of these integrations are already live and generating transaction volume.
On the Stellar network specifically, Wirex has launched live dual-stablecoin settlement in USDC and EURC, enabling real-time card payments settled directly on Stellar with on-chain transparency and near-instant finality. This integration is fully operational today and represents one of the most advanced real-world stablecoin payment deployments on Stellar to date .
From a growth perspective, Wirex BaaS is onboarding 2–5 new enterprise clients per month and is projected to issue 10+ million cards within the next three years, driving $60B+ in annual card volume and substantial on-chain settlement activity. This positions the proposed Stellar SDK not as a speculative initiative, but as infrastructure built on top of a live, scaling, and revenue-generating platform with immediate ecosystem impact .
Budget: $28,800
Completion Date: End of Week 5
Deliverables
D1.1 – Wallet Management Module (Stellar)
Stellar account creation and querying. Balance retrieval for XLM and issued assets (USDC, EURC). Trustline management. Non-custodial key handling abstractions.
D1.2 – Transaction Lifecycle Module
Transaction construction and client-side signing. Fee handling and submission via Horizon. Transaction status and lifecycle tracking.
D1.3 – Configuration Module
Testnet / mainnet environment switching. Network and endpoint configuration.
How to measure completion
Successful Stellar testnet transactions executed using the SDK.
Unit tests covering wallet and transaction flows.
Developer documentation available for all implemented modules.
Budget: $43,200
Completion Date: End of Week 11
Deliverables
D2.1 – Smart Contract Interaction Module (Soroban)
High-level Soroban contract invocation helpers. Parameter encoding and decoding. Consistent error normalization.
D2.2 – API Client Module
Unified client for Stellar and external services. Standardized response and error handling models.
D2.3 – WebSocket & Streaming Module
Real-time account and transaction event subscriptions. Network activity streaming.
D2.4 – Wirex Reference Integration (Testnet)
Demonstration of regulated payment flows connected to Stellar. On-chain settlement using XLM, USDC, and EURC. Non-custodial integration pattern serving as a reusable reference.
How to measure completion
End-to-end testnet payment flows executed via the SDK.
Live streaming events demonstrated.
Reference integration reproducible following published documentation
Budget: $57,600
Completion Date: End of Week 16
Deliverables
D3.1 – Mainnet-Ready SDK Release
Full mainnet support for all SDK modules. Compatibility with Horizon, Soroban, and Stellar assets (XLM, USDC, EURC).
D3.2 – Production Documentation & Examples
Developer usage guides. Example integrations and reference flows. Final API documentation.
D3.3 – Professional User Testing (SCF Requirement)
How to measure completion
External developer user testing. Feedback incorporation and final fixes.
Successful mainnet transactions executed using the SDK.
Tagged mainnet SDK release published.
Professional user testing completed and documented.
The project is led by Wirex in collaboration with Vottun as development partner. Together, the teams combine deep expertise in regulated payments, blockchain infrastructure, and developer tooling.
Vottun Team
Vottun is a blockchain infrastructure and SDK provider with long-standing experience delivering production-grade integrations across multiple networks, including Stellar since 2021.
The project is led by Vottun’s founders:
Luis Carbajo – Founder & CEO. Entrepreneur with extensive experience in blockchain infrastructure, digital identity, tokenization, and enterprise Web3 solutions. Luis has led multiple large-scale integrations with public institutions, fintechs, and blockchain ecosystems.
Marta Vallès – Co-founder. Recognized entrepreneur and product leader, with multiple awards including Forbes recognition and published work on female entrepreneurship. Marta leads product strategy, ecosystem development, and partner coordination.
Vottun is supported by a senior development team with expertise in:
Blockchain SDK and API design
Stellar & Soroban integrations
Secure wallet and transaction infrastructure
Enterprise-grade architecture and documentation
Wirex Team
Wirex is a global digital payments platform operating across multiple jurisdictions, with millions of users worldwide. The company was founded by:
Pavel Matveev – Co-founder & Executive Chairman
Dmitry Lazarichev – Co-founder
Wirex’s team brings deep expertise in:
Regulated payment infrastructure
Crypto-to-fiat and fiat-to-crypto systems
Compliance-first product design
Large-scale consumer and B2B fintech platforms
Together, Wirex and Vottun have the technical capacity, ecosystem experience, and operational maturity to deliver a reusable, high-quality Stellar SDK that benefits the wider developer community.
Sergi Martinez
Luis Carbajo
Marta Valles
Pavel Matveev
No other submissions.