ASO keyword tools, compared
Every ASO keyword tool models search volume and difficulty, because neither Apple nor Google publishes them. The estimates therefore differ between vendors while broadly agreeing on which terms are bigger than which — so choose on market coverage, workflow and what happens after the list is produced, not on whose numbers look most authoritative. The practical split is between research platforms that hand you a spreadsheet and tools that turn the shortlist into metadata you can ship.
Key takeaways
- No vendor has real volume data; every figure is modelled, so treat them as relative rather than absolute.
- Coverage of your specific storefronts matters far more than headline database size.
- Difficulty scores are the least comparable metric between tools — never mix them in one sheet.
- A keyword list is not the deliverable; metadata that uses the terms is.
How we compared them
Grouped by what they do with the keyword list rather than by database size, since vendors count their databases differently and none of the counts are verifiable. Market coverage is assessed on the storefronts an app team is most likely to publish in.
The keyword tools, by workflow
- 1
AppTweak
Best for: Depth for a dedicated specialist
Broad keyword coverage with difficulty and chance scores, competitor keyword overlap and export. Best when someone will actually interrogate the data.
- 2
Mobile Action
Best for: Teams also running Apple Search Ads
Organic keyword intelligence alongside Search Ads tooling, which lets paid query data validate organic term selection.
- 3
Sensor Tower
Best for: Portfolios and market-level questions
Keyword research inside a much larger market intelligence product. Overspecified if keywords are all you need.
- 4
appXL
Best for: Turning the shortlist into shipped metadata
Harvests candidate terms, scores them against your listing, then drafts the title, subtitle and keyword field inside store limits. Less raw data to explore by design.
- 5
Store autocomplete
Best for: Validating anything the tools tell you
Free and real. Any term a tool recommends should appear plausibly in autocomplete before it earns characters in your title.
How to judge volume estimates you cannot verify
Because volume is modelled, the only meaningful validation is internal consistency and cross-checking. Take ten terms you understand well — your brand, an obvious category head term, a term you know is niche — and see whether the tool's ordering matches reality.
If the ordering is sensible, the dataset is usable for comparing candidates. If a term you know is niche outranks your category head term, the model is poorly calibrated for your vertical and no amount of dashboard polish fixes that.
| Metric | Trustworthy for | Not trustworthy for |
|---|---|---|
| Volume estimate | Ranking candidates against each other | Forecasting installs |
| Difficulty score | Within one tool, one market | Comparing across tools |
| Chance or opportunity score | Shortlisting quickly | Justifying a decision on its own |
| Autocomplete presence | Confirming real demand | Estimating size |
Coverage is the thing to trial
Vendors quote total keyword counts, which is close to meaningless. What matters is whether the tool covers your storefronts, your language and your category with enough depth to find long-tail terms.
Trial with your own smaller markets first, not the US. Divergence between providers is widest in non-English storefronts, and that is where the tool either earns its price or quietly fails.
What happens after the list
- Decide which two or three terms the title and subtitle will actually commit to — the rest are for the keyword field and description.
- Check every candidate against your app honestly; ranking for a term you do not serve produces installs that churn.
- Write the metadata inside store limits, counting characters rather than eyeballing them.
- Record what changed and when, so the next ranking movement can be attributed.
Frequently asked questions
Which ASO keyword tool has the most accurate data?
None can be verified, because neither store publishes volume. Judge calibration instead: check whether a tool's ordering of terms you already understand matches reality in your market.
Are keyword difficulty scores comparable between tools?
No. Each vendor computes difficulty differently, so scores should never be mixed in one spreadsheet or compared across providers.
Do I need a paid keyword tool?
Not for a first pass. Autocomplete and competitor listings will find your obvious terms. Paid tools pay off for multi-market work and tracked history.
appXL Research
App Store Optimization Research Team
The appXL research team analyzes App Store and Google Play ranking data across the apps our agent manages, and publishes what it finds.