SEOUL · TOKYO · UNITED STATES · ONCHAIN
Payments and onchain,
built into the product flow.
JunleeBuild designs product and integration layers that help wallets, creator platforms and AI services use blockchain infrastructure without exposing its complexity. Onramp integration is being prepared for review and KYB with approved third-party providers.
J
ONRAMP
GAS
PRODUCT
SEOUL 37.5665° N
TOKYO · U.S.
From local money to product action, responsibilities stay separate.
PRODUCT SYSTEMS
What we built. What remains.
Open any product brief for the target user, four-step flow, sample interface, server implementation, security boundaries and current limitations.
J/01Market blueprint · Private pilot
SAMPLE UI · NO LIVE TRANSACTION
SAMPLE CONTROL PLANE
POLICYJapan market environment
01production-jp · illustrative
02JPY quote · Provider pending
03Policy version 04
04Sponsored spend · LOCKED
INFRASTRUCTURE
JGas Japan
Policy-controlled Base gas sponsorship after a third-party JPY on-ramp.A zero-custody integration blueprint connecting a Japanese user's first USDC purchase to the next onchain action.View product brief ↗J/02Market blueprint · Private pilot
SAMPLE UI · NO LIVE TRANSACTION
SAMPLE CONTROL PLANE
POLICYUnited States market environment
01production-us · illustrative
02USD eligibility · Provider pending
03Daily budget · SAMPLE
04Sponsored spend · LOCKED
INFRASTRUCTURE
JGas United States
Connect a provider-led USD on-ramp to a policy-controlled Base experience.A zero-custody integration blueprint reducing friction between a US user's USDC purchase and a usable Base application.View product brief ↗J/03Private pilot
SAMPLE UI · NO LIVE TRANSACTION
SAMPLE CREATOR CHECKOUT
SUPPORTOne support action the fan can verify
J
CREATOR SUPPORT
25.00 USDC010.01 USDC · fixed
02Base network
03Server-verified order
04OBS · anonymous event
CREATOR
Jaylink Live
Connect Base USDC support with the creator's live-stream experience.A non-custodial creator-support product with fixed 0.01 USDC links, server-verified receipts and OBS alerts.View product brief ↗J/04Local R&D
SAMPLE UI · NO LIVE TRANSACTION
LOCAL R&D PROTOCOL
HTTP 402From 402 to a verified response
GET
/v1/agent/data40201PAYMENT-REQUIRED
02EIP-3009 · STRUCTURAL
03Replay · protected
04Settlement · MOCK
payment-required → authorize → verify
INFRASTRUCTURE
Base x402 Agent Payments
Research a safe path for AI agents to understand and pay for USDC-priced APIs.A non-custodial, mock-first gateway combining x402 v2 challenges, EIP-3009 structural validation and an SDK.View product brief ↗J/05Cloud staging
SAMPLE UI · NO LIVE TRANSACTION
SANDBOX OPERATIONS
LEDGERFrom intent to ledger
01Treasury · approval required
02Provider · SANDBOX
03Inbox · idempotent
04Ledger · append-only
COMMERCE
USDC Payment Orchestrator
Coordinate USDC payments, provider adapters and ledgers through explicit approval boundaries.A sandbox-first reference system connecting payment intents, treasury, providers and append-only ledgers for cross-border commerce.View product brief ↗J/06Local R&D
SAMPLE UI · NO LIVE TRANSACTION
LOCAL R&D ORDER
ORDERA voucher flow separating order and issuance
01Order · SAMPLE
02Provider · NOT CONNECTED
03PIN · REDACTED
04Ledger · LOCAL R&D
COMMERCE
VoucherPort
Design Korea–Japan digital-voucher ordering, issuance and encrypted ledgers to fail closed.Applied-commerce R&D separating payment approval from provider fulfilment and encrypting sensitive immediate-delivery results.View product brief ↗ONRAMP PARTNER READINESS
API integration preparation · No approval claimedClear responsibilities, before integration.
JunleeBuild does not custody customer funds or digital assets. Once integrated, the selected onramp provider performs payment processing, identity verification and KYC/AML; JunleeBuild provides the product experience and secure server integration.
View partner review packTARGET INTEGRATION
Provider handles payment. Verified events advance product state.
Coverage discovery, checkout and webhook reconciliation remain separated behind server boundaries and stay in sample or sandbox mode until approval.Coverage
Validate country, asset and payment-method support from provider staging data.
Quote and checkout
Confirm fees and expected receipt before the provider handles KYC and payment.
Server verification
Verify signed webhooks through an idempotent inbox; secrets stay server-side.
Separate product consent
An onramp completion never auto-authorizes a support payment or product action.
HOW WE BUILD
Trust architecture, before features.
No custody of user assets
Private keys, seeds and customer assets stay with the user.
Stop when facts are unclear
Funding, provider responses, policy and account implementation must match before progression.
Secrets stay server-side
API keys and webhook secrets stay out of browsers, sample code and public logs.
Say only what we proved
Market blueprint, private pilot, staging and R&D are labeled separately. A demo is not settlement.
JUNLEEBUILD LABS
The lab behind what comes next.
Jaylink MCN Studio
A local studio for validating MCN markets, memberships and digital-content flows without real assets.
R&DOshi Bridge V3
A prototype exploring wallets, onramp choice and fan-support coupon experiences.
R&DRegulated USDC Architecture
A fail-closed reference using read-only screens and zero-value fixtures to validate responsibility boundaries.
R&DABOUT JUNLEEBUILD
From product design to operating boundaries.
JunleeBuild is a Seoul-founded product company. We turn AI, payments and operational infrastructure into clear product flows and prepare verifiable systems for Korea, Japan and the United States.
- Entity
- JunleeBuild Co., Ltd.Corporation registered in the Republic of Korea
- CEO
- Yeonjun Lee
- Founded
- February 10, 2026
- Address
- A705, Room 402, 4F, 20 Hakdong-ro 24-gil, Gangnam-gu, Seoul, Republic of Korea
START A CONVERSATION
Have a product to review together?
Talk to us about onramp partner review, sandbox integration and JGas or Jaylink pilots.