Hi all, quick heads up for teams integrating with Jupiter Prediction…

Hi all, quick heads up for teams integrating with Jupiter Prediction Markets API.

We’re shipping a coordinated migration to add fractional contracts support, scheduled for Wednesday, 27 May 2026 at 6:00 AM UTC (2:00 PM SGT, UTC+8).

Estimated downtime: up to ~4 hours (may complete earlier if everything goes smoothly).

What’s changing

Contract quantities are migrating from whole-contract units to micro-contract units, enabling fractional positions.

Example:

- Before: 5
- After: 5000000 micro-contracts (= 5 contracts)

This enables positions such as 5.777773 contracts, partial fills with exact fractional accounting, and better compatibility with external liquidity venues.

Order sizing precision: Effective fill sizes will be floored to 0.01-contract increments on the keeper to stay aligned with external venue precision. You can submit finer-grained sizes, but executed amounts will round down to the nearest 0.01.

Compatibility (non-breaking at deploy time)

Existing legacy fields will continue to work for backwards compatibility:

- contracts
- filledContracts
- totalContracts

New exact fields will be added:

- contractsMicro
- contractsDecimal

USD fields remain unchanged (still micro-USD). Orderbook sizes will be returned as decimal strings.

During the migration window

- Trading and order creation will be paused
- Claims and settlement will be paused
- Read APIs may be temporarily stale or inconsistent
- Integrators generally do not need to make changes to keep working after the migration

Recommended action

Legacy whole-contract fields will be deprecated roughly one week after the migration. Within that week, please migrate to the new exact-quantity fields:

- Use *Micro fields for calculations and order creation
- Use *Decimal fields for UI display
- Treat legacy whole-contract fields as compatibility-only

We’ll post another reminder closer to the maintenance window and confirm once the migration is complete. If you’re unsure how this affects your integration, reach out to @anmoldotsol and we’ll help verify.
May 26, 2026 1.3K