This is a draft. The final wording may change after a lawyer's review before release.

Rewards Rules

Last updated: September 26, 2026 (draft)

Rules version: rw_v4

1. In short

Rewards are a benefit of Pro. While you use Pro (a paid subscription, a free trial or the launch offer) points accrue automatically with nothing to sign up for; on the free plan nothing accrues.
You earn points for the days you complete the review quest and for long-term correct answers, and points are used only as a discount coupon on your next subscription payment. 1P = ₩1, and you can use points from 5,000P. On the monthly plan 5,000P is a 50% discount (₩4,950) and 9,900P makes the month ₩0. On the 4-month plan every 5,000P takes ₩5,000 off the price, and 29,900P makes the semester ₩0 (section 5).
Points are never used automatically. Go to Me → Rewards → [Use points for a discount], pick a tier, and the Google Play purchase sheet shows the discounted price; once you confirm, your next payment is charged at that price. One coupon per payment. Your card statement shows the lower amount that was actually charged.
Today's quest is complete when you finish all of today's due reviews (up to 20), have at least 10 counted answers that day, and have at least 60 active questions (section 3).
A ₩0 month (100%) takes 9,900P on the monthly plan. You reach that in one month with a quest every day of a paid month (30 days) with no misses, plus about 90 long-term correct answers in that month (about 120 if you miss one day in it). The 4 weeks before that month must also be near-daily (one miss at most) for each day to earn 300P. In a month with fewer points you can use the 50% tier, or keep saving and combine it with the next month.
Points build only during paid periods and trial or launch-offer periods (including remaining trial days moved back when you subscribe during a trial), and not during a month that points made ₩0. A month you paid for at a discounted price (for example ₩4,950) accrues as usual.
If you start with no study history, your record builds over the first 4 weeks, so even with a quest every day your first paid period earns in the 7,000P range. Your first payment is charged in full; these points can be used as a 50% coupon on your second payment.
Points have no cash value. They cannot be transferred or exchanged for anything else, and they disappear 12 months after you earn them or when you delete your account.
These rules apply together with the Terms of Service (section 8) and the Privacy Policy.

2. When rewards apply

Points accrue automatically while you use Pro — a paid subscription, a free trial or the launch offer alike. There is nothing to "join" or sign up for.
These rules are the document referred to in section 8 of the Terms of Service and apply together with the Terms you accepted when you signed up.
No points accrue on the free plan. Quest days (the "last 28 days" in section 3), however, are counted from what you actually studied whatever your plan, so a study habit you built on the free plan counts from the day you start Pro. On the free plan, after a session we may show "what you would have earned today on Pro" (nothing actually accrues).
When Pro ends, no new points accrue from then on; the points you already have stay and can be used as a coupon the next time you subscribe (section 5, within the expiry period).
Rewards need a confirmed e-mail address.
Rewards apply automatically while you use Pro; there is no switch to turn them off. If you switched them off in an earlier version, you can turn them back on with [Turn rewards back on] on the rewards screen, and the points you already have stay.
The time zone that decides where one reward day ends is fixed when rewards first apply to you. It does not move if you turn rewards off and on again, or if you change your phone's time zone (this keeps anyone from collecting the same day twice by hopping between time zones).

3. How points are earned

① Today's quest (once a day)

A day is a "quest day" when all three of these are met.

You finish all of the reviews due that day. On days with more than 20 due, finishing 20 is enough.
You have at least 10 counted answers that day (section 6). On days with fewer than 10 due, top up with Take a quiz or Retry mistakes in the Practice tab.
You have at least 60 active questions.

The day's points depend on how many quest days you have in the last 28 days, including today.

0–9 days: 20P
10–11 days: 25P
12–13 days: 30P
14–15 days: 40P
16–17 days: 55P
18–19 days: 75P
20 days: 100P
21 days: 120P
22 days: 150P
23 days: 180P
24 days: 215P
25 days: 250P
26 days: 285P
27–28 days: 300P

Roughly: 2 days a week or less earns 20P a day, 3 days 30P, 4 days 55P, 5 days 100P, 6 days 215P, every day 300P. Missing one day out of 28 (27 days) still earns the top 300P.
A missed day earns nothing, and for the next 4 weeks your daily points may sit one step lower. Once that day leaves the 28-day window it recovers by itself. There is no streak that resets to zero and no weekly or monthly gate.
Quest days are counted from what you actually studied, whatever your plan. When Pro starts (a first payment, subscribing again and so on) we fill the window once from your last 28 days of study, so days you studied on the free plan count too.

② Long-term correct answers — 10P each (up to 2,000P, i.e. 200, per calendar month)

Each counted answer that day earns 10P when all five of these hold: ① it was a due review ② it was in a format the app grades (not self-graded like flashcards, and not changed with "I got it right") ③ you did not use a hint ④ you got it right ⑤ it came more than 144 hours (6 days), by server time, after your previous counted answer on the same question.
These accrue even on study days when you did not complete the quest.
A higher score does not earn more. The app adjusts difficulty to hold everyone's accuracy at a similar level. Instead we count how many answers you remembered long-term by reviewing steadily.

Examples — a 30-day paid period with the same habit in the 4 weeks before it, calculated straight from the rules. The number of long-term correct answers is an assumption and differs from person to person. Monthly plan; points below 5,000P are not used and simply keep building.

About 2 days a week (9 quest days): 9 × 20P = 180P + about 225P from long-term correct answers = about 405P → not usable yet (from 5,000P). At this pace it takes a little over a year to reach one 50% coupon.
3 days a week (13 days): 13 × 30P = 390P + about 390P = about 780P → not usable yet. A little over half a year of saving reaches a 50% coupon.
4 days a week (18 days): 18 × 55P = 990P + about 540P = about 1,530P → not usable yet. A 50% coupon in the fourth month.
5 days a week (22 days): 22 × 100P = 2,200P + about 770P = about 2,970P → two months of saving reach a 50% coupon (₩4,950).
6 days a week (26 days): 26 × 215P = 5,590P + about 1,040P = about 6,630P → a 50% coupon every month, or save two months for a ₩0 month.
Every day (30 days): 30 × 300P = 9,000P + about 1,350P = about 10,350P → a ₩0 month (9,900P), with about 450P left over.
With a 28-day paid period such as February, even a quest every day gives 8,400P + about 1,260P = about 9,660P. You can use a 50% coupon and keep 4,660P, or earn just 240P more in March for a ₩0 month. Fewer days simply means proportionally less.
Even with a quest every day of the paid month and 100 long-term correct answers, the result depends on the 4 weeks before: every day → about 10,000P (a ₩0 month) · 6 days a week → about 9,000P (a 50% coupon, the rest carries over) · weekdays only → about 7,000P · 3 sick days just before the payment → about 8,000P · a 4-week break before coming back → about 4,000P (not usable yet).
Studying 6 days a week keeps the window around 24 days, so one month earns 6,000–7,000P. If you make both the 4 weeks before and the paid month near-daily, for example around exams, you reach 9,900P in a month.
If you sign up with no study history and complete the quest every day from day one: 330P during the 14-day trial and 7,000P during the first 30-day paid period (quests only), so you can use a 50% coupon on your second payment (about 7,100–7,700P including long-term correct answers). 6 days a week gives about 3,800–4,900P, so the coupon comes a month later; weekdays only gives about 1,600–2,000P, so it takes about three months of saving. Your first payment is charged in full.

4. Limits

Monthly limit: 10,000P, counting today's quests and long-term correct answers together, by the calendar month of the day the points accrue. Anything above it does not accrue.
Long-term correct answers: up to 2,000P (200) a month.
Holding limit: 30,000P. When the points you hold reach 30,000P, that day's points accrue only up to the limit and the rewards screen tells you. The limit is large enough to reach a ₩0 semester on the 4-month plan (29,900P). Use a coupon before you reach it.
Pre-payment points: up to 3,000P. Points earned during a trial or the launch offer (including points from earlier versions of these rules) build up to 3,000P. That is below 5,000P, so your first payment is charged in full; keep earning after it, and from 5,000P you can use a coupon on the following payment (section 5).
Which days accrue: a day (in the time zone from section 2) accrues if any part of it falls in a period you paid for, or in a trial or launch-offer period. A paid period at a coupon-discounted price is still a paid period. A month that points made ₩0 (including a period we deferred your billing date for, section 5) does not accrue (your quest-day record carries on). Remaining trial days moved back when you subscribe during a trial accrue like paid days.
These numbers are server settings. If they change, we update this document and the app together and tell you in advance under section 9.

5. Using points — a discount coupon on your next payment

Points are used only to turn them into a discount coupon for the next payment of that account's paid subscription. 1P = ₩1, and you can use points from 5,000P. Below 5,000P they are not used and simply keep building.
A coupon is chosen from fixed tiers. Google Play auto-renewing subscriptions cannot be charged an amount our server reduces individually for each person; the only way is for you to pick a discounted product we prepared in advance.

Tiers (based on the monthly plan at ₩9,900 and the 4-month plan at ₩29,900. If plan prices change, tier prices change in the same proportion, with notice under section 9. The Play purchase sheet shows the price in your local currency.)

Monthly plan: 5,000P → 50% discount (₩4,950) · 9,900P → 100% discount (the month is ₩0)
4-month plan: 5,000P → ₩5,000 discount (₩24,900) · 10,000P → ₩10,000 discount (₩19,900) · 15,000P → ₩15,000 discount (₩14,900) · 20,000P → ₩20,000 discount (₩9,900) · 25,000P → ₩25,000 discount (₩4,900) · 29,900P → 100% discount (the semester is ₩0)
Only tiers your balance can pay for are offered. Even if you hold more than one tier's worth, one payment uses one tier.

How to use points

Me → Rewards → [Use points for a discount] → pick a tier → the Google Play purchase sheet shows the discounted price → once you confirm, your next payment is charged at that price. Nothing is charged now.
Points are deducted only after you confirm in the Google Play purchase sheet. If you back out of the sheet, or the purchase cannot be confirmed, your points stay as they were.
One coupon per payment. The discount applies to that one payment only; the payment after it is charged at the full price again, and you can use a new coupon from the points you have saved by then.
Nothing happens automatically. From 7 days before your next payment until the payment date, if you hold 5,000P or more and have not used a coupon yet, the Today tab shows one line: "N P — you can get a discount on your next payment". We do not send device notifications for this.
After you use a coupon, the rewards screen shows something like "From your next payment (date): ₩4,950 · N P left".

When you can use points (if any of these is not met, the button is disabled and the reason is shown. Your points stay.)

You have an active paid Pro subscription with auto-renew on. While cancellation is scheduled there is no next payment, so a coupon cannot be used; turn auto-renew back on and you can.
No plan change is waiting to take effect. You can use points after the change.
Not during a grace period, while the account is on hold, or while the subscription is paused.
No "under review" flag (section 8) is open.
You have not used a coupon in the current billing cycle.
The discounted product for that tier is ready in the store. Until it is, the tier shows "Not ready yet" and becomes usable once it is.

If the subscription ends after you used a coupon

If the subscription is cancelled or expires before the payment the coupon applied to, the coupon is void and the points you used are returned. Returned points can be used for another 12 months from the day they are returned.
Once the discounted payment has been made, points are not returned.

A ₩0 month (100%)

The 9,900P tier on the monthly plan (29,900P on the 4-month plan) makes that payment ₩0. If the store does not allow a ₩0 product, we provide the same benefit by moving your billing date back one cycle. For you it is the same thing: "this payment ₩0 · a free month".
No points accrue during a month that points made ₩0 (or a deferred period) (section 4).

Your first payment (trial → first payment)

Points earned during a trial or the launch offer (pre-payment points, section 4) stop at 3,000P, so they are usually below 5,000P. Your first payment is charged in full; keep earning after it, and from 5,000P you can use a coupon on the following payment.
If you already hold 5,000P or more when you buy your first subscription (for example points from an earlier version of these rules), you can pick a tier on the plans screen and get the discount on your first payment.

The 4-month plan

It works the same way: every 5,000P takes ₩5,000 off, and 29,900P makes the semester ₩0. The 4-month plan is charged once every 4 months, so a coupon can be used once every 4 months, and the holding limit (30,000P) is large enough to reach a ₩0 semester.

Refunds (including withdrawal within 7 days and cancellation of a minor's purchase)

A refunded payment does not count as a payment.

① The points earned during that payment's period are taken back (down to the balance you hold).
② If a payment discounted with a coupon is refunded, the points spent on that coupon count as used and are not returned.
Points cannot be exchanged for Pro days, money, gift cards or crypto-assets, and cannot be given or sold to anyone else.

6. What counts as an answer

A study day is the day the server receives your answers (in the time zone from section 2). Answers given offline count on the day they sync. Changing your device clock does not change this.
The same question counts once per day.
To earn credit again for a scheduled review of the same question, at least 20 hours must have passed since the previous counted answer on it.
Answers tapped too quickly do not count (under 1.2 seconds for multiple choice and true/false, under 2 seconds for typed answers).
Easier practice rounds, where you retry a question in a simpler format, are not recorded at all.
Self-graded answers (flashcards, "I got it right") count toward the quest. Long-term correct answers (section 3 ②), however, count only answers the app graded.
The 144 hours for long-term correct answers are measured from the times the server received the answers, not from any value the app sends.

7. When it becomes final

Each day (today's quest and long-term correct answers) is settled by the server after midnight in the time zone recorded when rewards first applied to you (section 2).
The server checks hourly for anything to settle, so it lands within a few hours of midnight. Opening the rewards screen also settles your own days right away.
Before settlement the figures shown are an estimate and may differ from the final result.
The same day is never settled twice.
When the quest points table changes (section 9), days are split by study date: days studied before the new table's effective date are settled with the old table, and days from that date with the new one.

8. "Under review" (holds)

If any of the following shows up, the points for that period are held rather than paid, and a person reviews them.

More than 40% of a week's answers were too fast.
Answers are mostly implausibly fast (median response time, or typing speed per character).
Guess-corrected accuracy (κ) is below 0.15 — checked only when a week has at least 60 objectively graded answers without hints.
Your own grading frequently disagrees with the actual answer.
A batch of old answers was uploaded all at once.
Reviews were repeatedly pulled forward far earlier than scheduled.
Each month we sample-check the top 1% of earners. A hold is considered if accuracy on long-term correct answers stays at 98% or more with very fast answers for 4 weeks.

What a hold means.

While a period is held the app shows "Under review", and you cannot use a coupon until the review ends (section 5). A coupon you already used stays as it is.
If the review finds nothing wrong, the held points are paid in full. If abuse is confirmed, that period's points are not paid, and repeated cases can cost you your rewards eligibility.
If there is no conclusion within 14 days, up to 3,000P is paid automatically; anything above that is paid once the review ends.
If you studied honestly and were held anyway, tell us through Me → Settings → Send feedback and a person will look again.
A hold does not lock your account. It only delays that period's payout.

9. Changes to these rules

Changes in your favour (more points, or lower requirements) can take effect from the day we announce them.

Changes to your disadvantage are made only for the following reasons and within the following limits.

① Reasons: when the rewards can no longer be sustained on the current terms — for example, discounts given for points exceed 22% of all subscription payments for two months in a row or 25% in one month, or more than 5% of payments use a ₩0-month coupon for two months in a row · to stop abuse · when laws or store policies change
② Notice: we announce what changes and why in the app (rewards screen and Today tab) 30 days before it takes effect.
③ Limit: one change reduces the points for the same study by no more than 20%, at most once a quarter (except for abuse measures and legal or policy changes).
④ Timing: never in the middle of a month — the change applies to points accruing from the 1st of the month after the 30-day notice.
⑤ What we keep: the value of points you already have (1P = ₩1), the 5,000P minimum for using points, and the 12-month expiry do not change. Tier prices change only in proportion to plan prices. The only exception is a change required by law or store policy, and even then we keep the 30-day notice in ②.

If you do not like a change, you can turn rewards off or cancel your subscription; points you already have can still be used (within 12 months).
If we end rewards altogether, we will tell you 60 days in advance, and points earned by then can still be used as coupons until they expire.
A change raises the version number (for example rw_v4 to rw_v4.1), and past versions stay on the web without being deleted (section 13).

Automatic adjustment — set in advance, so no one picks a convenient moment to change things.

Only the rows for 26 or fewer quest days in the last 28 days in the section 3 ① table can change. The every-day row (27–28 days, 300P) and long-term correct answers (10P each, 2,000P a month) are never changed automatically. So the ₩0-month condition in section 1 is not affected by automatic adjustment.
Decisions start only after 6 months have passed since paid subscriptions went on sale in the app and there are at least 100 paying subscribers. They use the discount share (discounts given for points ÷ subscription payments) adjusted for how long people have subscribed, and figures from third and later payments, and act only when a condition holds for two months in a row.
Reduce: when the discount share (adjusted for subscription length) exceeds 22% of all subscription payments for two months in a row or 25% in one month, or more than 5% of payments use a ₩0-month coupon for two months in a row → the rows for 26 or fewer days go down by 10%. Each row is rounded to 5P, rows close to 26 days drop less, neighbouring rows differ by 45P at most, and no row drops more than 20% from its current value. It is announced 30 days ahead and applies to points accruing from the 1st of the following month, at most once a quarter and twice in 12 months. If the alarm continues after two reductions, there are no further automatic reductions.
Table after one reduction (example): 0–9 days 20P · 10–11 days 25P · 12–13 days 25P · 14–15 days 35P · 16–17 days 50P · 18–19 days 70P · 20 days 90P · 21 days 110P · 22 days 135P · 23 days 160P · 24 days 195P · 25 days 225P · 26 days 255P · 27–28 days 300P
Raise: when the discount share (adjusted for subscription length) is below 12%, and among third and later payments fewer than half used a coupon, or the average discount for diligent payments (22+ quest days in that paid period) is below 35%, for two months in a row → the same rows go up by 10%. At most once a quarter and once in 12 months, applying to points accruing from the 1st of the following month.

What changed from rw_v3 to rw_v4 (changes that may be to your disadvantage first)

Points are used as a discount coupon on your next payment instead of pushing back your billing date. Nothing applies automatically: you tap [Use points for a discount] yourself and confirm in the Google Play purchase sheet.
Points can be used from 5,000P (rw_v3 applied every 1,000P as 3 days, automatically). Points below 5,000P are not used and keep building.
You choose from fixed tiers only (50% and 100% on the monthly plan; six tiers in ₩5,000 steps on the 4-month plan).
One coupon per payment.
If a discounted payment is refunded, the points spent on that coupon are not returned.
In your favour: the value of a point rose slightly from 1,000P = 10% of a month's price (₩990) to 1P = ₩1 (1,000P = ₩1,000); a ₩0 month now takes 9,900P instead of 10,000P; the holding limit rose from 12,000P to 30,000P; the free-time limit per payment (one month on the monthly plan, two on the 4-month plan) is gone, so the 4-month plan can reach a ₩0 semester. The discount shows on your card statement as the lower amount actually charged. You choose when to use points, and if the subscription ends before the payment the coupon applied to, your points are returned. A paid period at a discounted price (other than ₩0) still accrues points.
Points you already have keep their value at 1P = ₩1. A billing-date deferral already scheduled under rw_v3 is still applied.

What changed from rw_v2 to rw_v3 (changes that may be to your disadvantage first)

The quest changed from "at least 5 due reviews + at least 5 counted answers" to "all due reviews (up to 20) + at least 10 counted answers + at least 60 active questions".
The weekly goal (150P a week) is gone.
Points do not accrue during free time from points.
Points are not applied while auto-renew is off, during a grace period or while the account is on hold.
Free time from points is at most one month per payment (two on the 4-month plan).
Instead of choosing a discount step when you pay, your billing date is pushed back automatically 4 days before your next payment (the date changes, not the amount).
In your favour: the most one payment can receive rose from 30% to 100% (one month), the daily quest from 30P to 20–300P, the monthly limit from 1,500P to 10,000P and the holding limit from 3,000P to 12,000P, and long-term correct answers now earn a bonus. Quest days count from what you studied whatever your plan. The value of points you already have (1,000P = 10% of a month's price) is unchanged.

10. Expiry, and deleting your account

Points expire 12 months after the day you earn them. When you use points, the oldest are used first.
From 30 days before points expire, the rewards screen shows "XP expire on (date)".
Deleting your account deletes your points and reward records immediately and permanently. Remaining points are not restored or compensated in cash or otherwise.
For deleted accounts we keep only a monthly total (how many accounts, how many points) that cannot be traced to anyone, used only to reconcile our points liability.

11. Things to keep in mind

The largest benefit (100%, a ₩0 month) is available only on a payment after you have saved 9,900P on the monthly plan (29,900P on the 4-month plan). A near-daily paid month (including the 4 weeks before it) with about 90 long-term correct answers reaches it in one month; with less, you can save over several months or use the 50% tier. The conditions in section 5 (auto-renew on and so on) must be met to use a coupon.
The share of subscribers who actually used a coupon last month is published on the plans and rewards screens in the app (section 12).
Points earned before billing opens (during a trial or the launch offer) build up to 3,000P; keep earning after your first payment, and from 5,000P they can be used (section 4).
Rewards exist to help you keep studying. They are not income or a side job.
Working around these rules, for example with several accounts or automation tools, breaks the Terms of Service.
Contact: Me → Settings → Send feedback, or support@iterialab.com

12. How results are published

The plans screen, the rewards screen and notes from Mirimi show the share of last month's Pro subscribers who used a coupon and the average discount. We do not use it in store descriptions or notifications.
Month shown: only the most recently finished calendar month (visible from the 1st of the next month). We never pick a good month or go back to an earlier one.
First month published: the first calendar month that starts after 6 months have passed since paid subscriptions went on sale in the app. For example, if sales started on April 15, November's results (the first month after October 15) are shown from December 1. Nothing is published before that, even with enough subscribers, because right after launch everyone has only just paid and the share comes out much lower than it really is.
Sales start date and first month published: [판매 시작일] → [처음 공개하는 달] (filled in on the day sales start)
Denominator (n): everyone who had a paid subscription period on at least one day that month — including people who turned rewards off, have 0P or have cancellation scheduled, and excluding trial-only users and deleted accounts.
Used a coupon: people who had a payment that month actually charged at a coupon-discounted price ÷ n. People who saved points but did not use them, or whose coupon was not applied because they cancelled, count as not having used one.
Average discount: the discount on each payment that month (capped at 100% per payment) added up and divided by n, counting people who used nothing (0%).
₩0 month: people whose payment that month used the 100% tier (a ₩0 month or a ₩0 semester) ÷ n.
Only months with n of 30 or more are published; otherwise nothing is shown. Shares are whole percentages rounded down, and anything above 0 but below 1% is shown as "<1%".
The three figures are shown at the same size and weight, together with the month and n.
Published figures are kept on the server for at least 6 months.

13. Where to find these rules

In the app: Me → Rewards → Read the full rules. You can also open the Terms of Service under Me → Settings and switch to the "Rewards" tab.
On the web: iterialab.com/mirimi/rewards/
Past versions: iterialab.com/mirimi/rewards/rw_v3/ · iterialab.com/mirimi/rewards/rw_v2/ (past versions are kept, never deleted).
This version (rw_v4) applies from the day the server's rules version changes to rw_v4.

This document is still a draft. The final wording may change after a lawyer's review before release.