How to Research App Store Keywords
For Free in 2026

App Store Optimization starts with one question: which keywords should you target? Get this right, and your app appears where people are already searching. Get it wrong, and you're either invisible or buried under competitors you can't beat.

The problem is that most ASO keyword research tools charge $50–$200 per month, require accounts, and send your competitive research data to their servers. If you're an indie developer or a small studio, that's a hard sell — especially when you're still validating whether your app idea has traction.

That's why we built RespectASO — a free, open-source, self-hosted ASO keyword research tool. It runs in a Docker container on your machine, uses only the public iTunes Search API (no API keys needed), and gives you popularity scores, difficulty analysis, download estimates, competitor breakdowns, and rank tracking across 30 App Store countries. The source code is on GitHub under the AGPL-3.0 license.

This post teaches the process of ASO keyword research — general concepts that apply regardless of what tool you use — while demonstrating each step with RespectASO so you can follow along.

What Makes a Good Keyword?

Every ASO keyword can be evaluated on three dimensions:

The sweet spot is a keyword with decent popularity, manageable difficulty, and strong relevance to your app. In practice, that's a spectrum. RespectASO classifies each keyword with a targeting advice label to help you prioritize:

These classifications come directly from the popularity and difficulty scores. They're a starting point — you still need to apply your own judgment about relevance and brand positioning. But they quickly separate the keywords worth investigating from the ones you can skip.

Step 1: Set Up the Tool

RespectASO runs as a Docker container. You need Docker installed — nothing else. No accounts, no API keys, no sign-up forms.

The first build takes roughly 30 seconds. After that, the container starts in seconds and restarts automatically with Docker — no need to run the command again after rebooting your machine.

Everything runs locally. The only network calls are from your machine to Apple's public iTunes Search API to fetch search results. No data is sent to Respectlytics or any third party. Your keyword research stays on your machine.

Step 2: Add Your App

Before you start searching keywords, add your app on the Apps page. You can either search by name or paste an App Store URL. When you add an app via App Store lookup, RespectASO fetches its metadata (icon, developer name, bundle ID) and — crucially — enables rank tracking.

With rank tracking enabled, every keyword search will show where your app currently ranks in the top 200 results for that keyword. Without adding your app, you still get all the keyword scores — you just won't see your own ranking position.

You can also add apps manually (just a name, no App Store lookup) if you want to organize keywords by project without rank tracking.

Step 3: Search and Evaluate Keywords

On the Dashboard, type your keywords into the search bar — up to 20 at a time, comma-separated. Select the country (or up to 5 countries simultaneously) and optionally associate the search with one of your tracked apps. Hit Search.

For each keyword and country combination, you get:

• Popularity score (5–100) — Estimated from 6 signals derived from competitor data: the number of search results, leader strength (review counts of top apps), keyword-in-title density, market depth, a specificity penalty for long-tail phrases, and an exact phrase match bonus.
• Difficulty score (1–100) — A weighted composite of 7 factors: rating volume (30%), dominant players (20%), review velocity (10%), rating quality (10%), market age (10%), publisher diversity (10%), and title relevance (10%). Labels range from Very Easy to Extreme.
• Download estimates — Estimated daily downloads for each ranking position from 1 to 20, with conservative and optimistic ranges. The model converts popularity to daily searches, applies position-based tap-through rates, then factors in install conversion rates.
• Competitor analysis — The top 25 apps currently ranking for that keyword, with their ratings, review counts, and pricing.
• Ranking tiers — Separate difficulty analysis for Top 5, Top 10, and Top 20 positions, because the competition at position 3 is different from position 15.
• Targeting advice — An automatic classification (Sweet Spot, Hidden Gem, Good Target, Avoid, etc.) based on the popularity-difficulty combination.
• Your app's rank — If you added your app via App Store lookup, you see your current position in the top 200 results.

How to Read the Scores

Neither popularity nor difficulty should be evaluated in isolation. A keyword with popularity 80 and difficulty 85 might drive a lot of searches, but you're competing against deeply entrenched apps with hundreds of thousands of reviews. A keyword with popularity 35 and difficulty 15 won't bring a flood of downloads, but you can realistically reach the top 5.

The download estimates help bridge this gap. They translate abstract scores into tangible numbers: "If I rank #3 for this keyword, I could get roughly 50–80 downloads per day." That makes it easier to compare a high-volume/high-difficulty keyword against a moderate-volume/low-difficulty one in terms of actual impact.

A practical approach: start with keywords that the tool classifies as Sweet Spot or Hidden Gem. These give you the best chance of ranking quickly and generating downloads while you build up your app's store presence. Once your app has a stronger rating and review base, you can target the more competitive terms.

Step 4: Find Your Best Markets

Most developers research keywords only in their home market. But the same keyword can have wildly different popularity and difficulty in different countries. A keyword that's fiercely competitive in the US might be a Hidden Gem in Germany or Brazil.

RespectASO's Country Opportunity Finder lets you search a single keyword across all 30 supported App Store countries at once. It ranks the results by an opportunity score: Popularity × (100 - Difficulty) / 100. Countries where the keyword has solid search volume but weak competition float to the top.

The 30 supported countries span North America, Europe, Asia, the Middle East, South America, and Oceania: US, UK, Canada, Australia, Germany, France, Japan, South Korea, China, Brazil, India, Mexico, Spain, Italy, Netherlands, Sweden, Norway, Denmark, Finland, Portugal, Russia, Turkey, Saudi Arabia, UAE, Singapore, Thailand, Indonesia, Philippines, Vietnam, and Taiwan.

After the scan completes (it takes about 60–90 seconds to check all 30 countries), you can select the most promising markets and save them to your search history. This gives you a localization roadmap: which countries to prioritize for keyword-localized metadata.

Step 5: Track Changes Over Time

ASO is not a one-time task. Keyword competition shifts as new apps launch and existing apps gain or lose momentum. RespectASO tracks your keywords over time so you can spot trends.

• Daily auto-refresh — A background scheduler automatically refreshes all your tracked keyword-country pairs every day. No manual action needed.
• Trend charts — Click any keyword in your history to see how its popularity, difficulty, and your app's rank have changed over time.
• Trend arrows — The dashboard shows ↑/↓ indicators next to each metric, comparing today's values to the previous data point so you can spot changes at a glance.
• 90-day retention — Historical data is automatically cleaned up after 90 days to keep the database lean.

You can also manually refresh individual keywords or bulk-refresh all keywords for a specific app when you want fresh data immediately.

To take your data elsewhere, use CSV export. It exports your full search history — keyword, app, country, popularity, difficulty, rank, competitor count, and date — with optional filters by app or country.

Why Open Source and Self-Hosted Matters for ASO

Most ASO tools are black boxes. They show you a difficulty score of 47, but you have no idea how they calculated it. Is a 47 actually hard? What signals are they using? Are two tools even measuring the same thing when they both say "difficulty"?

RespectASO takes a different approach: every algorithm is open source. The difficulty score is a weighted composite of 7 factors — you can read exactly how rating volume, dominant players, review velocity, rating quality, market age, publisher diversity, and title relevance are weighted and combined. If you think a factor should be weighted differently, you can change it.

Being self-hosted also means:

• Your competitive research stays private — Your keyword lists, competitor analysis, and market research never leave your machine. With cloud ASO tools, the provider sees every keyword you research.
• No usage limits — There's no tier-based cap on how many keywords you can search. The only throttle is a 2-second delay between API calls to stay respectful of Apple's public API.
• No vendor lock-in — Your data lives in a local SQLite database. Export it as CSV anytime. If you stop using the tool, your data is still yours.
• Free forever — Because it runs on your machine, there's no infrastructure cost for us to pass on to you. No trial periods, no feature gates.

The trade-off is honest: a self-hosted tool requires Docker on your machine, and the scores are estimates — not official Apple data. But for keyword research, estimates from transparent algorithms beat black-box numbers from a paid tool every time, because you can evaluate and improve the methodology yourself.

Frequently Asked Questions