Publication date: April 7, 2026
JEPX System Upgrades: Shift to API-Based Trading Reshapes Market Access
JEPX will begin rolling out its upgraded trading system from April 2026, with a phased transition across spot and intraday markets extending through FY2026. The key change lies in the migration from browser-based trading to API (Application Programming Interface) -driven infrastructure. Under the new system, JEPX will phase out its existing GUI (Graphical User Interface) entirely, shifting to server-to-server communication via dedicated lines.
This effectively means that:
- Market access will no longer be possible via standard web interfaces after the transition period
- Participants must connect through dedicated network lines and APIs
- Trading operations will become more automated and system-driven
For the spot market, the new system goes live on April 1, 2026. The current system will remain available in parallel during the transition period, with its interface scheduled to be discontinued at the end of March 2027.
For the intraday market, the transition follows later, with the new system applying to deliveries from October 1, 2026, while the current system will continue to handle transactions up to September 30, 2026.
Regarding fees, for FY2026, annual membership fees and transaction fees will remain unchanged at current levels (annual fee: JPY 360,000–600,000; spot trading fee: JPY 30/MWh; intraday trading fee: JPY 100/MWh).
🔍 Shulman Commentary: The shift to API-based trading and dedicated line connectivity introduces new cost layers, with communication and system integration fees raising the baseline for market participation. This is likely to favor larger, automated players while raising barriers for smaller retailers to maintain direct market access.
JEPX System Upgrades: Shift to API-Based Trading Reshapes Market Access
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