Loading...
Supporting developers, startups, and full-fledged companies building on Stellar and Soroban
© 2025 Stellar Development Foundation
Subscribe to the Newsletter
By Blockroll
1. Stellar-Native Wallet Infrastructure (DFNS) Stellar role: Wallet-as-a-Service with MPC key security and HSM backing. Manages all user Stellar accounts, USDC and DeFindex vault trustlines, and transaction signing via API. Impact: Replaces Circle Wallet for all Stellar operations. Every other integration in this submission depends on DFNS — without Stellar-native wallets, Blockroll cannot settle, hold, or move USDC on Stellar.
2. International Fiat Settlement via Bridge Stellar role: Bridge provides USD/EUR/GBP virtual account numbers for each Blockroll user and converts incoming fiat into USDC on Stellar. Impact: Nigerian freelancers receive a US, European, or UK bank account number that funnels international payments directly into their Stellar USDC balance. It removes the friction of asking clients to use crypto while protecting income from naira volatility.
3. Stablecoin Visa Card (Bridge) Stellar role: Card balance is funded directly from the user's Stellar USDC balance, with each top-up settled as a Stellar payment operation to Bridge. Impact: Users spend their Stellar USDC balance globally at any Visa-accepting merchant with no naira conversion, no devaluation loss, and no exposure to parallel market rates.
4. Standards-Based On/Off-Ramp (Stellar Anchor Platform, SEP-24 / SEP-31) Stellar role: Blockroll implements the SDF-maintained Anchor Platform standard, letting any compliant Stellar anchor plug in for NGN ↔ USDC conversion. Linkio is the first anchor integrated; future anchors include Busha and Yellowcard. Impact: One integration unlocks every current and future Stellar anchor. It gives users dual-source liquidity, competitive rates, and failover redundancy as more anchors come online, without Blockroll writing a custom code each time.
5. On-Chain Yield (DeFindex) Stellar role: Users deposit idle USDC into DeFindex vaults directly from their Stellar wallet. Vault tokens represent the user's yield-bearing position and redeem back to USDC on Stellar. Impact: Idle balances become productive. Nigerian users earn real on-chain yield on their dollar savings.
6. Stellar Compliance Gate (Sumsub) Stellar role: Sumsub runs KYC and AML screening at user signup before any Stellar wallet is provisioned. Once the user is active, Sumsub continuously monitors all transaction flows that fall outside Bridge's compliance scope: peer-to-peer transfers, DeFindex vault activity, and Anchor Platform on/off-ramp transactions. Impact: Replaces Smile ID as the gating layer for access to the entire Stellar + Fiat stack. Without Sumsub clearing a user, no Stellar wallet is created, no USDC flows, no yield, and no card is issued. Provides the regulatory coverage required to operate stablecoin settlement and yield at scale.
Partner Readiness & Timeline Feasibility
Linkio: We have production API access to Linkio and have completed KYB with them. Linkio supports our primary corridors: NGN for Nigerian users and USD, EUR, and GBP for the countries our users predominantly receive funds from. The partnership is finalized and operationally ready.
Bridge: We have production API access to Bridge’s account services and have completed KYB. Bridge supports the same corridors. For the Bridge Card service specifically, we are in the final stage of activation; the remaining step is depositing a float to initiate the service and starting the card program, which is within our original milestone timeline.
Compliance: All necessary compliance flows are in place. Through our integration with Sumsub, we'll handle AML screening, transaction monitoring, and KYC verification as a unified compliance layer. All local and international partners we work with are licensed and regulated in their respective jurisdictions.
The timeline feasibility for both partnerships is intact; neither integration requires work beyond what is already scoped in our original milestones.
Differentiation & Stellar Migration Plan
Why Blockroll is different
Blockroll is not building another dollar-access app. The Nigerian market already has many. We are building Nigeria's first stablecoin wealth platform; combining payments, yield, and card rewards in a single mobile product for Nigerians who want to do more than just hold dollars.
Our differentiation rests on three pillars no competitor in Nigeria currently has all together:
1. Visa card with cashback on Stellar USDC funding: The Blockroll Card rewards users who fund their card with USDC on Stellar with enhanced cashback, creating a direct economic incentive to transact using Stellar USDC. Every card top-up is a Stellar payment operation from the user's DFNS wallet to Bridge's card funding address.
2. Yield on idle USDC balances, exclusively on Stellar: Most competitors hold users' dollars and give them nothing in return. Blockroll puts idle USDC to work on Stellar through our DeFindex integration, earning passive on-chain returns without users needing to move funds out of the app. Yield is exclusively Stellar-native, creating a direct economic incentive for users to keep their balances on Stellar.
3. First stablecoin neobank in Nigeria serving both adults and teens: With our compliance infrastructure and partnerships, we have the regulatory and banking relationships to onboard verified users across age groups (teens + adults) under one platform. No competitor has built this. We are not just acquiring today's users; we are building the first product that introduces a Nigerian teenager to dollar savings, yield, and card rewards alongside their parents.
Stellar as the Default Settlement Layer — Not an Add-On
Stellar is not a feature in Blockroll. It is the default settlement layer for every dollar that flows through the product.
Every new Blockroll user is provisioned a Stellar-native MPC wallet via DFNS after successful onboarding, before any fiat touches the system. All new international fiat settlement, yield, card funding, and on/off-ramp flows are exclusively Stellar. Existing operations on Solana and Base continue unchanged:
International fiat (USD, EUR, GBP) arrives via Bridge virtual accounts and automatically settles as USDC on Stellar into the user's DFNS wallet
NGN on/off-ramp runs through Linkio via the Stellar Anchor Platform (SEP-24/SEP-10)
Card spending is funded directly from the user's Stellar USDC balance via Bridge's Cards API, with each top-up executed as a Stellar payment operation signed by DFNS
Yield is earned on idle Stellar USDC via DeFindex vaults, entirely on-chain and entirely on Stellar
For existing users on Solana and Base, migration to Stellar is incentive-driven rather than forced. Yield is only available on Stellar USDC. Card cashback rewards are only available when funding with Stellar USDC. The NGN on/off-ramp via Linkio will run exclusively on Stellar. Users who want yield, card rewards, and the full Blockroll experience will naturally consolidate their balances on Stellar, because that's where the value is.
This means every Blockroll user, by default, holds and transacts on Stellar, without needing to understand or care about the underlying network. There is no migration required for new users because there is no off-Stellar path. From the moment they sign up, their financial life inside Blockroll is Stellar.
This is not a theoretical architecture. It is the build plan we are executing across three tranches with four SCF building blocks: DFNS, Bridge, Stellar Anchor Platform via SEP-24/SEP-10, and DeFindex.
$125.0K
Blockroll has been live in production for 8 months with verifiable traction:
iOS App Store: https://apps.apple.com/us/app/blockroll/id6708225786 — 4.5 stars
Google Play Store: https://play.google.com/store/apps/details?id=com.blockroll.android — 4.3 stars
Website: https://www.blockroll.app
Some internal metrics (screenshot): https://drive.google.com/drive/folders/1nQJ4XbSj8PIpiP4MJb34J6VQD4-TxcF- — 1,490+ users, 10,000+ transactions, $350K+ volume, 23% AU
Screenshots of Signed agreements with Anchor and Quidax (redacted): https://drive.google.com/drive/folders/1hKhJWVT-Jx8C0ZgVIX7MkVNEtKhWbtxQ
Private community: Blockroll Whatsapp Community (300+ members): https://chat.whatsapp.com/HcpMtz2iidnFYmECWFViOz
This tranche establishes the foundation every other integration depends on: compliance-gated user onboarding, Stellar-native wallet infrastructure via DFNS, and working USDC settlement on Stellar testnet. Each deliverable includes the backend integration, the associated mobile UI screens, and the design work to integrate new flows into the existing Blockroll app experience.
Deliverable 1.1: DFNS Wallet Infrastructure + Stellar Account Provisioning — $10,000
Integrate DFNS Wallets-as-a-Service for Stellar-native MPC wallet creation, with accompanying mobile screens for wallet creation, balance display, and transaction history. On user signup, Blockroll provisions a Stellar account through DFNS, funds the minimum XLM reserve, and establishes USDC and DeFindex vault token trustlines automatically.
Scope:
DFNS API integration for Stellar account creation
Automatic trustline setup (USDC, DeFindex vault tokens)
XDR signing via DFNS MPC
Internal wallet service layer routing Stellar operations through DFNS
Error handling and retry logic for account provisioning
Mobile UI: wallet creation flow, Stellar balance display, transaction history screens
Design work integrating the new wallet experience into the existing Blockroll app
How to measure completion:
End-to-end testnet demo: user signs up → Stellar account created via DFNS → USDC trustline established → DeFindex vault trustline established
Successful USDC send and receive on Stellar testnet signed by DFNS
Mobile app displays real Stellar balances and transaction history
Recorded walkthrough of the full flow on testnet
Deliverable 1.2: Sumsub Compliance Gate for Stellar Onboarding — $8,000
Integrate Sumsub as the KYC and AML gate that sits in front of Stellar wallet provisioning, with the accompanying mobile onboarding flow. No user receives a Stellar wallet until they clear Sumsub verification. Replaces Smile ID as Blockroll's primary compliance provider.
Scope:
Sumsub KYC flow integrated into Blockroll's signup
AML screening on all new users
KYC state persistence in Blockroll's backend
Trigger logic that provisions a DFNS Stellar wallet only after Sumsub clears the user
Blocked-user handling for failed KYC cases
Mobile UI: redesigned onboarding flow with Sumsub integration, KYC status screens, rejection and retry flows
Design work ensuring the new compliance flow feels seamless inside the existing app
How to measure completion:
Test user passes Sumsub KYC and automatically receives a Stellar wallet via DFNS
Test user fails Sumsub KYC and is blocked from wallet provisioning
Sumsub verification events logged and traceable in Blockroll's backend
Mobile app displays KYC states (in progress, approved, rejected, retry)
Recorded demo of both paths (approved and rejected)
Deliverable 1.3: USDC Settlement Layer + Horizon Monitoring — $7,000
Build the core USDC settlement layer using the Horizon REST API for account and transaction queries and Horizon streaming for real-time inbound payment detection. Includes the mobile UI for peer-to-peer USDC transfers between Blockroll users.
Scope:
Horizon REST API integration for account balances and transaction history
Horizon streaming for real-time inbound USDC payment detection
Internal transaction ledger tracking all Stellar USDC movements per user
Blockroll user balance updates triggered by Horizon events
Peer-to-peer USDC send and receive between Blockroll users on testnet
Mobile UI: send/receive USDC screens, transaction confirmation, real-time balance updates
Design work for the peer-to-peer transfer flow
How to measure completion:
Inbound USDC on testnet appears in the receiving Blockroll user's balance within 10 seconds of Stellar confirmation
Peer-to-peer USDC transfer between two Blockroll users on testnet completes and reflects correctly in both balances
Mobile app shows real-time transaction status and history
Transaction history in Blockroll matches Stellar testnet explorer records
Recorded demo of send, receive, and peer-to-peer USDC flows
Tranche 1 Total: $25,000
This tranche builds out the complete feature set on Stellar testnet: Bridge-powered multicurrency accounts and Visa card, standards-based on/off-ramp through the Stellar Anchor Platform with Linkio as the first anchor, and on-chain yield via DeFindex. Each deliverable includes the backend integration, associated mobile UI, and design work. By the end of Tranche 2, all four official SCF building blocks are integrated and working end-to-end on testnet.
Deliverable 2.1: Bridge Multicurrency Virtual Accounts — $12,000
Integrate Bridge's API to provide each Blockroll user with USD, EUR, and GBP virtual account numbers, along with the mobile screens for viewing account details and tracking inbound deposits. Incoming fiat deposits are automatically converted and settled as USDC on Stellar.
Scope:
Bridge API integration for virtual account provisioning (USD, EUR, GBP)
Bridge native KYC flow triggered when users opt into multicurrency services
Automatic USDC on Stellar settlement for inbound fiat deposits
Webhook handling with signature verification, replay protection, and idempotency
Reconciliation logic cross-referencing Bridge events against on-chain Stellar transactions
Mobile UI: virtual account listing, account details screens, deposit tracking, Bridge KYC flow
Design work integrating multicurrency accounts into the existing Blockroll experience
How to measure completion:
Testnet demo: USD virtual account created for a test user, simulated USD deposit, automatic USDC arrival in the user's Stellar wallet, confirmed via Horizon
virtual_account.activity.updated webhook received, verified, and processed without duplicate crediting
Reconciliation job successfully matches Bridge activity logs with Stellar on-chain transactions
Mobile app displays virtual account numbers and tracks inbound deposits in real-time
Deliverable 2.2: Bridge Visa Card Integration — $10,000
Integrate Bridge's Cards API to issue Visa cards funded directly from users' Stellar USDC balances, with the complete mobile card management experience. Card activation runs through Bridge's onboarding flow, and funding is executed as Stellar payment operations from the user's DFNS wallet to Bridge's card funding address.
Scope:
Bridge Cards API integration using Stellar as the funding chain
Virtual card creation flow
USDC-to-card-balance funding via Stellar payment operations signed by DFNS
Card transaction webhook handling with idempotency and replay protection
Reconciliation of card balance against Stellar on-chain funding transactions
Mobile UI: card activation flow, card details screen, funding interface, transaction history, card controls (freeze/unfreeze)
Design work for the full card management experience
How to measure completion:
Testnet demo: card creation in Blockroll, USDC transfer from user's Stellar wallet to Bridge funding address, card balance reflects funded amount
Stellar transaction verifiable on testnet explorer
card_account.updated webhook received, processed, and confirmed against card balance
Mobile app shows card details, funding flow, and transaction history end-to-end
Deliverable 2.3: Stellar Anchor Platform (SEP-24 / SEP-10) — $10,000
Implement a Stellar Anchor Platform client following SEP-24 (interactive deposit/withdrawal) and SEP-10 (web authentication) standards, with the mobile flows for on/off-ramp. Linkio is integrated as the first anchor for NGN ↔ USDC conversion on Stellar. The SEP-24 interactive flow is embedded inside the Blockroll Flutter app so users complete anchor confirmation without leaving the app experience.
Scope:
SEP-10 authentication flow between Blockroll backend and Linkio
SEP-24 interactive deposit and withdrawal client
Embedded in-app confirmation flow for the anchor interaction
Linkio integrated as the first anchor for NGN ↔ USDC
stellar.toml publication with TRANSFER_SERVER_SEP0024 configuration
Transaction state tracking across anchor lifecycle (pending, completed, failed, refunded)
Webhook callbacks and status polling for anchor transaction updates
Mobile UI: NGN withdrawal and deposit screens, embedded SEP-24 confirmation, transaction status tracking
Design work for seamless on/off-ramp flows that feel native to Blockroll
How to measure completion:
End-to-end testnet withdrawal: user initiates NGN withdrawal in Flutter app → SEP-10 authenticates → SEP-24 flow opens embedded in the app → user confirms → USDC sent from user's Stellar address to Linkio → NGN disbursement confirmation received via webhook
End-to-end testnet deposit: user initiates NGN deposit → SEP-24 flow opens → user pays NGN to Linkio → USDC arrives at user's Stellar address via DFNS
SEP-10 authentication successful between Blockroll backend and Linkio
Complete flow recorded as a demo showing the user never leaves the Flutter app
Deliverable 2.4: DeFindex Yield Vault Integration — $5,500
Integrate DeFindex vaults so users can deposit idle USDC into yield strategies and earn on-chain yield directly on Stellar, with the accompanying yield dashboard in the mobile app. Users see live yield positions and can withdraw principal plus accrued yield back to their Stellar wallet.
Scope:
DeFindex vault deposit flow (USDC in, vault tokens out) signed by DFNS
Real-time yield position tracking via vault NAV queries
Withdrawal flow (vault tokens in, USDC plus yield out)
Mobile UI: yield dashboard with deposited amount, current value, accrued yield, live APY display, deposit and withdraw flows
Design work for the yield experience, making DeFi yield approachable for retail users
How to measure completion:
Testnet demo: user deposits USDC into a DeFindex vault, vault tokens appear in the user's Stellar account
Live yield position accurately reflects vault NAV in the Blockroll app
User successfully withdraws from the vault and receives USDC (principal plus accrued yield) back to their Stellar wallet
APY and position values displayed in the app match on-chain vault data
Tranche 2 Total: $37,500
This tranche takes the full Stellar integration suite from testnet to Stellar mainnet, hardens the production stack, and refines the mobile UX based on findings from SCF's professional user testing. By the end of Tranche 3, real users are sending USDC, earning yield through DeFindex, spending via Bridge Visa cards, and moving money through Linkio — all on Stellar mainnet.
Deliverable 3.1: Mainnet Deployment of All Integrations — $17,000
Deploy DFNS, Bridge, Stellar Anchor Platform (with Linkio), and DeFindex on Stellar mainnet. This includes full production configuration, secrets management, staging validation, and pre-launch testing across all four integrations.
Scope:
Production deployment of all four integrations on Stellar mainnet
Mainnet API keys, secrets management, and environment configuration for DFNS, Bridge, Linkio, and DeFindex
Production database migrations and infrastructure scaling for Stellar transaction load
DNS, SSL, and domain configuration for all production endpoints
Staging environment validation with production-equivalent configuration
Pre-launch integration testing across all flows (settlement, card, on/off-ramp, yield)
How to measure completion:
All four integrations live on Stellar mainnet with real production API credentials
Real USDC settlement via Bridge verifiable on Stellar mainnet explorer
Real Bridge Visa card funded from a real Stellar USDC balance
Real DeFindex vault deposit and withdrawal completed on mainnet
Real Linkio NGN withdrawal completed via the SEP-24 flow on mainnet
Staging environment matches production and passes full integration test suite
Deliverable 3.2: UX Refinement from User Testing — $9,000
Following SCF's professional user testing with real users, ship UX fixes and refinements to the Stellar integration flows. This deliverable focuses on iterating on the mobile experience based on real user feedback, not building new UI from scratch. The CPO leads design iteration based on real usage data.
Scope:
Review findings from SCF-provided professional user testing
Prioritize and fix high-impact UX friction points across all Stellar flows
Refine onboarding, wallet creation, Bridge card, DeFindex yield, and Anchor Platform withdrawal and deposit screens based on user feedback
Before/after documentation of changes shipped
Iterative design work by the CPO based on real usage data, including variations where appropriate
Update design system for Stellar-integrated flows
How to measure completion:
User testing report with documented findings
Log of UX changes shipped in response to findings (before/after screenshots)
Updated production app reflecting refinements
Signed-off design system updates for Stellar-integrated flows
Deliverable 3.3: Sumsub Transaction Monitoring for Stellar Flows — $7,000
Extend the Sumsub compliance layer to monitor all Stellar USDC flows that fall outside Bridge's native compliance scope. This includes peer-to-peer USDC transfers between Blockroll users, DeFindex vault deposits and withdrawals, and Linkio Anchor Platform transactions.
Scope:
Sumsub transaction monitoring API integration for Stellar transaction events
Event emission from Blockroll's backend on every USDC flow outside Bridge's scope
AML screening and suspicious activity detection rules configured in Sumsub
Alert routing for flagged transactions with manual review workflow
Transaction monitoring coverage verification across peer-to-peer, DeFindex, and Linkio flows
How to measure completion:
Sumsub receives and processes transaction events for all Stellar flows outside Bridge
Test transactions (simulated high-risk patterns) trigger alerts and land in the manual review queue
Monitoring coverage report shows all Stellar USDC flows outside Bridge are tracked in Sumsub
Compliance team can review, approve, or escalate flagged transactions from the Sumsub dashboard
Deliverable 3.4: Production Hardening — $14,000
Harden the full Stellar integration stack for production. This includes webhook replay protection, idempotency enforcement, retry logic, reconciliation jobs, monitoring dashboards, alerting, load testing, and integration testing across all four building blocks.
Scope:
Webhook replay protection and idempotency across Bridge, DFNS, Linkio, and DeFindex callbacks
Retry logic and exception handling for all Stellar transaction failures
Reconciliation jobs cross-referencing on-chain Stellar transactions against internal ledger state
Monitoring dashboards (Sentry for errors, PostHog for product analytics, custom dashboards for Stellar transaction volumes)
Alerting for failed transactions, webhook errors, reconciliation discrepancies, and stuck flows
Load testing of all integration endpoints
End-to-end integration testing across all four building blocks
Incident response runbooks for each integration
How to measure completion:
Load test of 100 concurrent transactions across all four integrations passes without data loss or duplicate state changes
Reconciliation jobs run every 15 minutes with zero unexplained discrepancies over a 48-hour test window
Alert system tested with simulated failures across each integration (Bridge webhook failure, DFNS signing timeout, Linkio webhook replay, DeFindex vault timeout)
Integration test suite passes end-to-end for all user flows
Incident response runbooks reviewed, tested, and stored in the repository
Deliverable 3.5: Developer Documentation + Operational Runbooks — $3,000
Publish public technical documentation for Blockroll's Stellar integration, internal operational runbooks for incident response, and a live metrics dashboard tracking Stellar transaction volume, yield TVL, and card spending.
Scope:
Public architecture documentation describing the Stellar integration layer
Internal runbooks covering incident response, reconciliation procedures, webhook replay, and manual transaction recovery
Post-launch metrics dashboard showing Stellar transaction volume, DeFindex TVL, Bridge card spending, and Linkio on/off-ramp volume
API documentation for internal teams
How to measure completion:
Public documentation published and accessible
Internal runbooks reviewed with the team and stored in the repository
Metrics dashboard live and updating in real-time
Architecture diagrams finalized and accessible
Tranche 3 Total: $50,000
Blockroll is a team of 10 builders, engineers, designers, and ex-founders who are also the product's primary users. The four people below form the core team executing the Stellar integration. We have firsthand experience with the exact problem we're solving: receiving international payments and protecting income from naira volatility. Collectively, the team brings 6+ years of blockchain and crypto product experience.
Core Stellar build team:
Sadiq Isiaka — CEO & Technical Product Manager. Experienced in leading product teams and building digital communities, including Web3 and AI Connect (12,000+ members) and the GenZ Founders Club (250+ members). Background spans UX research, cloud engineering, product management, and 6+ years in blockchain. linkedin.com/in/sadiqannes
Stephen Adeyemo — CPO & Product Designer. Has designed and shipped financial and crypto products at Hashit and Kavlr, serving tens of thousands of users across B2B and B2C. linkedin.com/in/stephen-adeyemo-b14910111
Paul Ugochukwu — Backend Engineer. 4+ years building secure mobile and web software including Arewabooks, with deep experience in crypto and blockchain development using Rust, Node.js, and TypeScript. github.com/ugochukwudev
Samuel Olaleye — Fullstack Developer. Experienced across Flutter, Dart, Next.js, and Solidity, building across web2 and web3. github.com/SamuelAdex
The broader team brings experience from OPay, Wallets Africa, Hashit, Kavlr, and NFTNG, and has previously shipped products including Scribstack and Hivvy. We are executors first: resourceful, product-obsessed, and building something we use every day.
Ugochukwu Paul
STEPHEN ADEYEMO
Samuel Olaleye
Sadiq Isiaka
By Blockroll
Stablecoins Remittance Mobile App for African Remote Workers