The restrictions per request are as follows and are common to both the Production and Test Environments:
Market by Order (MBO): 50,000 messages Standard: 250,000 messages (ToSTNeT information: 35,000 messages)

For TCP Retransmission requests, it is possible to use multiple simultaneous connections with different IP addresses. In the FLEX service for both the Test and Production Environments, functions such as individual message retransmission requests via TCP, backup requests, and snapshot requests are provided in order to recover messages after a message drop is detected via UDP multicast on the user-side system, etc.
When using the functions, please strictly follow the specifications and procedures specified in the chapter 2 "TCP" of the FLEX Connection Specification TCP Transmissions, chapter 4.1 "Retransmission and Snapshot via TCP" and chapter 7 "Compliance" of the FLEX Market by Order Specifications.

Please note that if any violations of the above are identified, TCP Retransmission requests from the relevant user may be restricted.
*If you expect a large number of errors during testing in the Production Environment on holidays or in the Test Environment on weekdays, please contact the JPX Service Desk (arrowhead/ToSTNeT) <arrowhead@jpx.co.jp> in advance. (Please refrain from testing in the Production Environment on weekdays.)

*The "FLEX Connection Specifications" and "FLEX Market by Order Specifications" are posted at the following sites:
[System Documents Site] arrowhead/ToSTNeT/FLEX > Connection Specifications (FLEX) Related
-Log in with your Target JPX Site ID or arrowface ID
URL: https://faqsd.jpx.co.jp/category/show/621?site_domain=en_system_documents

-Log in with dedicated (existing) ID
URL: https://faqsd.jpx.co.jp/end_user_login?site_domain=en_system_documents&id=621&redirect_controller=category&redirect_action=show