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Earn yield on crypto assets through fixed-term and flexible lending plans — 13 API endpoints for full lifecycle management.

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Capabilities

The Crypto Lending API supports two plan types with distinct yield mechanics.
  • Fixed plans — lock assets for 10-360 day terms. Interest paid at maturity. Interest ratio conversion when target currency differs from source currency.
  • Flexible plans — deposit and withdraw anytime. Interest calculated hourly, credited daily. Auto-reinvestment option compounds returns.
  • ~90 supported assets — invest in a wide range of crypto assets (check available plans dynamically via the plans endpoint)
  • Auto-invest — configure automatic recurring investments into Flex plans
  • Full lifecycle API — create, monitor, withdraw, and close investments programmatically

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Who Uses This

  • Yield integrators — fintechs and platforms offering lending products to end users via API. Fetch available plans, create investments on behalf of customers, track earnings.
  • Treasury operations — exchanges and trading firms putting idle Main balance assets to work in Flex plans between active trading periods.

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Common Integration Patterns

Yield-as-a-service — Fetch available Flex plans via POST /api/v4/main-account/smart-flex/plans. Present plan options (asset, interest rate) to end users. Create investments via POST /api/v4/main-account/smart-flex/investments/invest. Track earnings through POST /api/v4/main-account/smart-flex/investments/payment-history. Enable auto-reinvestment for compounding. Idle asset management — Monitor Main balance for idle assets. Invest surplus into Flex plans (withdraw anytime, no lock-up). Set up auto-invest for recurring allocation. Withdraw back to Main balance before trading.

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Plan Types

Lending API access: Both Fixed (/api/v4/main-account/smart/) and Flex (/api/v4/main-account/smart-flex/) lending endpoints require B2B partner permissions. Complete the institutional services form to request access. Until access is granted, these endpoints return 403 with "You don't have permission to use this endpoint. Please contact support for more details".

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Technical Overview

  • 13 endpoints total (5 fixed + 8 flex), all POST, all authenticated
  • Authentication: HMAC-SHA512 (guide)
  • Rate limits: 1000 requests per 10 seconds per endpoint (details)
For full endpoint documentation, see the Crypto Lending API Reference.

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Platform Context

The WhiteBIT platform brands lending products as U EARN. The platform also offers Staking and Auto-Invest for recurring purchases — available via the platform UI, not the API.

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What’s Next

Quickstart

Create a first Flex investment in under 5 minutes.

API Reference

Full endpoint documentation for all 13 lending endpoints.