When I started doing App Store localization work, I expected the results to be gradual and hard to attribute. Update metadata, wait a few weeks, maybe downloads go up a little, hard to tell if it was the localization or something else.
That's not what happened.
After working through 43 localizations across apps in productivity, health, utilities, education, and finance — covering markets from Japan to Brazil to South Korea to France — the patterns are consistent enough that I'd call them reliable. Here's what I've learned.
Lesson 1: The First Market You Localize Is Almost Always Japan
Not because I recommend Japan first in every case — I sometimes recommend Germany or Brazil depending on the app — but because Japan is usually where developers have the highest existing download count with zero localization investment.
The pattern: a developer checks their App Store Connect analytics and discovers they're already getting 20–50 downloads a month from Japan with English-only metadata. No Japanese keyword field, no Japanese subtitle, sometimes the title is English, and yet Japanese users are still finding and downloading the app somehow — usually through direct App Store browse or word of mouth.
When I localize the Japanese metadata, those 20–50 monthly downloads turn into 200–400 within 60 days. The demand was already there. The keyword coverage was missing.
If you open App Store Connect right now and filter your downloads by territory, I'd bet Japan shows up in your top 5 or 10 markets even if you've never localized for it. That's the signal.
Lesson 2: Translated Keywords Almost Never Match What Users Search
This one surprises developers the most.
The instinct when localizing is to take your English keyword list, translate each term, and use the translations as your international keywords. "Habit tracker" → "Gewohnheits-Tracker" in German. "Focus timer" → "タイマー集中" in Japanese. Done.
The problem: users don't search the direct translation of English terms. They search the way they naturally describe the thing in their own language — which is often completely different from how English speakers describe the same thing.
A focus timer app in Germany gets more searches for "Arbeitszeit" (work time) and "konzentriert arbeiten" (work concentrated) than for "Fokus Timer." A meditation app in Japan gets strong results for "瞑想" (meiso — meditation) but also for "マインドフルネス" (mindfulness, a loanword) and "リラックス" (relax). Neither of those last two is a direct translation of anything obvious.
The only way to know what actually gets searched is to start from native-language keyword research tools and look at what users type — not from translating your existing English keywords.
Lesson 3: The Subtitle Has Higher Impact Than Most Developers Expect
I've run enough before/after comparisons now to say with confidence: properly used, the subtitle moves rankings more than developers expect.
The most common state I see: an app with a decent keyword in the title, a blank or generic subtitle, and an underoptimized keyword field. The quick wins in this situation are almost always in the subtitle.
When you add a researched keyword to a previously blank subtitle, you get two things: the keyword itself is indexed at a high weight, and Apple's combination logic now uses that keyword alongside your title terms. The ranking surface area expands noticeably — often within 2–3 weeks.
A developer I worked with had a journaling app with "Journal" in the title and a generic subtitle ("Your thoughts, organized"). Replacing the subtitle with "Daily Diary & Mood Tracker" added rankings for "daily diary," "mood tracker," "diary app," and "mood journal" within three weeks. None of those terms had been in the metadata before. The subtitle change did more for their search visibility than a month of keyword field tweaks.
Lesson 4: Japan Is Harder to Localize Than Every Other Market — and Worth It More
I said Japan is usually the first market developers prioritize. I should also say it's the most complex to do correctly.
Japanese metadata requires decisions that don't come up in European markets: which script to use for which terms (hiragana, katakana, kanji, romaji, or a combination), how to handle compound words, whether loanword versions or native Japanese versions of category terms have higher search volume.
Machine translation handles Japanese worse than any other language I've worked in. It tends to produce technically correct Japanese that reads unnaturally to native speakers and sometimes selects the wrong script for a given context. Apps with machine-translated Japanese descriptions convert significantly worse than apps with properly localized copy.
The investment required to do Japanese correctly is higher than Germany, France, or Brazil. The return, in most categories, is also higher — because the market is larger, the revenue per user is stronger, and the behavioral signal accumulation from Japanese users tends to be particularly strong.
I've seen Japanese localization turn into a top-3 market for apps in 6 categories: productivity, utilities, health, finance, education, and creative tools. In every case, the app had been available in Japan for months or years with zero meaningful Japanese metadata before the localization project.
Lesson 5: Brazil Downloads Fast, But the Competition Gap Is Closing
A few years ago, Brazil was an extraordinarily easy market to rank in. Properly localized metadata for a mid-size niche app could reach the top 5 for primary Brazilian Portuguese keywords within 2–3 weeks, with almost no competition in the way.
That's still largely true, but I've noticed more well-localized apps entering Brazilian search results in the past 12 months. The gap is closing — slowly, but closing. Developers are realizing the opportunity.
The practical implication: if Brazil is on your localization list, do it now rather than later. The developers who localize for Brazil in 2025–2026 will have a behavioral signal advantage over apps that enter the market in 2027–2028, because ranking history and accumulated downloads compound over time.
Lesson 6: The Keyword Field Is Filled Wrong More Often Than It's Blank
I expected the most common keyword field problem to be empty fields. What I actually find more often: fields that are filled but filled incorrectly.
The most common mistakes, in order of frequency:
Commas instead of spaces. Developers put "habit,tracker,daily,routine" instead of "habit tracker daily routine." Apple splits on commas, creating multi-character delimiters that waste space and create weird keyword combinations.
Repeating title words. The title says "Habit Tracker" and the keyword field starts with "habit tracker." Apple already indexes the title — this wastes the first 12 characters of 100.
Full phrases instead of individual words. "habit tracker for daily routines and building good habits" as a phrase uses 53 characters and covers one specific search pattern. The same words space-separated let Apple combine them into dozens of potential search matches.
English keywords in non-English locales. A Japanese keyword field containing "habit tracker" in English. Japanese users don't search in English for this category; the field contributes nothing.
Fixing these mistakes in an existing keyword field — without any new keyword research — often produces ranking improvements within 2–3 weeks. That's how common the errors are.
Lesson 7: The Apps That Win Long-Term Treat ASO as a System, Not a Task
The developers with the strongest long-term App Store performance aren't the ones who did the best single localization project. They're the ones who built a system: localize, track, iterate every 3–6 months, add new markets when the data suggests they're ready.
Metadata isn't permanent. Competitors update theirs. Search behavior shifts. Apple adjusts the algorithm. An app that localized perfectly in 2023 and never touched the metadata again is slowly losing ground to competitors who revisit their keyword strategy regularly.
The best time to localize is before you have a large user base, because early behavioral signals from a new market compound over time. The second-best time is now, even if you have existing rankings, because the competitive gap in international markets closes gradually.
If you want the localization done properly — keyword research from real App Store data, competitor gap analysis, and metadata that doesn't repeat any of the common mistakes above — that's exactly what LocalizeRank delivers. Starting at $49 for 5 markets.