Japan · Data feed
Use J-Quants data for backtesting with your AI coding agent.
Super Algo Kit lets you use J-Quants data for backtesting Japanese stock strategies inside your own AI coding agent. J-Quants is a JSON data API from a Japan Exchange Group company, with prices and financial statements by plan. The kit sizes calls to your plan's limit and labels delayed free-plan data. For live quotes and orders, it pairs J-Quants with a broker card.
broker facts
J-Quants API
- What it is
- A JSON data API from JPX Market Innovation and Research, a Japan Exchange Group company. Data only, no orders.
- Coverage
- Japanese listed equities, daily prices and financial statements; indices, futures and options on higher plans.
- Access model
- Register, choose a plan and issue an API key. Accounts opened from 22 December 2025 use version 2 only.
- Free option
- Free plan at 0 yen: 5 calls a minute, 2 years of history, 12-week delayed data, no CSV.
- Rate limits
- From 5 calls a minute on Free to 500 on Premium. Heavy repeated excess can block access for about 5 minutes (reported).
- Costs
- Paid plans from 1,650 to 16,500 yen a month, plus add-ons for minute and tick data and for TDnet.
- History
- 2 years on Free, rising to 20 years on Premium; the minute and tick add-on covers 2 years.
- Licence
- The terms prohibit sharing or redistributing the data in a viewable form.
From the kit's J-Quants card, checked 2026-09-29. Confirm current terms on J-Quants's own site.
Paper first
A J-Quants bot, built paper first.
Super Algo Kit runs inside the coding agent you already use. It interviews you, writes the spec with pass marks set first, then builds, backtests and paper-tests. Real money starts only when you type the authorize command.
The plan, step by step
Tick them off as you go.
How does J-Quants API access work for backtesting?
You register on the J-Quants site, choose a plan and issue an API key in the dashboard. Accounts registered from 22 December 2025 can use version 2 of the API only. Older code samples may still show the version 1 flow.
J-Quants serves end-of-day and historical data as JSON over plain HTTPS. It is not a live feed and cannot place orders. A live bot pairs it with a broker card such as kabu STATION API.
The kit keeps the key in your environment, never in the repository or chat. Because the terms ban sharing, the kit treats the key as yours alone. It never embeds the key in a product other people use.
Paper trading and the J-Quants free plan
The free plan costs 0 yen and works as a trial. It allows 5 calls a minute and 2 years of history, with data delayed 12 weeks. That is fine for research and pipeline tests, but it cannot drive live signals.
Super Algo Kit never presents results from delayed data as live, or as a paper result, without a delay label. For the paper stage, it pairs J-Quants history with a broker card such as kabu STATION. There the kit paper broker runs over live board data.
J-Quants limits, history and costs to plan for
Rate limits run from 5 calls a minute on Free to 500 on Premium, a 100-fold spread. If you keep exceeding the limit by a wide margin, access may be blocked for about 5 minutes (reported). History depth also grows by plan, from 2 years on Free to 20 years on Premium.
Paid plans run from 1,650 to 16,500 yen a month. Add-ons cover minute and tick data and TDnet company announcements. Whether these prices include consumption tax is not confirmed. Check the J-Quants site before you budget.
The Tokyo cash close moved from 15:00 to 15:30 on 5 November 2024 (reported). Older intraday data ends at 15:00, and the kit's calendar applies the 15:30 close only from that date.
What Super Algo Kit does with J-Quants
The data adapter uses one client with a per-minute budget sized from your plan, minus a safety margin. On a rate-limit reply it waits for the budget to refill, never retrying in a tight loop. It never runs bulk backfills in parallel.
Raw replies are cached by request and date. Until split and rights adjustments are confirmed, the series is treated as possibly restated. Dates in Japan time are converted to UTC at the adapter edge.
Every report built on the free plan carries its delay label. The kit's data contract records that redistribution in a viewable form is forbidden. A public dashboard or shared notebook with raw series can breach the terms.
Before you rely on it
Gotchas to plan for.
- The free plan is 12 weeks delayed; a live-looking bot on it would trade on stale data.
- A backfill script written on a Premium key stalls or gets blocked on Light or Free (reported).
- Prices before 5 November 2024 belong to a 15:00 close; mixing them breaks session-aligned bars (reported).
- History is capped by plan, so a longer backtest needs a higher plan or another source.
- Split and rights adjustments are not confirmed; store raw replies and treat series as restatable.
- Sharing raw J-Quants series in a public dashboard or notebook can breach the terms.
FAQ
J-Quants: questions.
Can I use J-Quants data for backtesting a trading bot?
Yes, for end-of-day and historical work. J-Quants serves Japanese listed-equity prices and financial statements, with 2 to 20 years of history by plan. Super Algo Kit builds a J-Quants adapter and runs cost-aware backtests with out-of-sample and walk-forward checks.
Is the J-Quants free plan enough for live trading?
No. Free-plan data is delayed 12 weeks and allows 5 calls a minute, so it cannot drive live signals. Use it for research and pipeline tests. For live quotes and orders, pair J-Quants with a broker such as kabu STATION API.
Is Super Algo Kit affiliated with J-Quants or JPX?
No. Super Algo Kit is independent software and is not affiliated with or endorsed by J-Quants or Japan Exchange Group. The name is used only to say the kit works with the documented J-Quants API. You hold your own J-Quants plan.
Can I paper trade with J-Quants data?
J-Quants is a data service, so it has no paper trading of its own. Super Algo Kit runs the paper stage through a broker card, such as kabu STATION with the kit paper broker. Anything built on delayed free-plan data carries a delay label.
Can I share J-Quants data on a website or dashboard?
The J-Quants terms prohibit sharing or redistributing the data in a viewable form. A public dashboard or shared notebook with raw series can breach them. Commercial-use terms are not confirmed in the kit's card, so confirm with the vendor.
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J-Quants API and its logo are trademarks of their owner, used here only to say that Super Algo Kit can work with it. Super Algo Kit is not affiliated with or endorsed by J-Quants. Super Algo Kit is development software. It is not investment advice, a signal service or a promise of performance. Trading involves substantial risk, including the loss of all capital you trade with.