Shipping an app to the App Store is the easy part. Getting it found is harder, and for most indie developers the cheapest growth lever is App Store Optimization (ASO): choosing the keywords people actually search for and putting them in your title, subtitle, and keyword field. You can't do that well by guessing, which is why a keyword research tool is one of the first paid tools many Apple developers buy.

Astro, RespectASO, Appfigures, and AppTweak cover very different ends of the market. Two are native Mac apps built for solo developers, and two are web platforms built for teams that also publish on Google Play. This guide compares them on keyword data, rank tracking, limits, platform support, and current pricing.

Quick Verdict

Choose Astro if you want a polished native Mac app with unlimited keywords and apps for one flat annual price.

Choose RespectASO if you want free, open-source keyword research on your Mac, with optional AI automation you pay for once instead of on a subscription.

Choose Appfigures if you also want sales, downloads, and reviews reporting in one place, or you publish on Google Play as well as the App Store.

Choose AppTweak if you're a growth team or agency that needs deep market data, organic install estimates per keyword, and Apple Ads tooling.

Feature Comparison

Astro

Astro has become the default ASO tool for many indie iOS developers, and it's easy to see why. It's a clean, native Mac app that shows everything important in one view: your keywords, their popularity, how hard it is to reach the top 10, and where your app ranks today.

Popularity data comes from Apple Search Ads, the same source most ASO tools rely on for the App Store. Astro updates rankings daily and keeps historical charts, so you can see whether a metadata change moved anything. It also knows which keywords your app already ranks for, suggests new ones, and can pull the keywords your competitors rank for. Other useful extras include a ratings view that shows which storefronts brought in new reviews, and DeepL integration so you can hover over a foreign keyword and see its English translation, which helps a lot when you localize metadata.

The pricing is the main draw. Astro costs $108 a year (shown as $9/month billed annually) for a single Mac license, with no limit on apps or keywords. Most web tools charge more as your keyword list grows. There's a 14-day refund window after you subscribe.

The trade-offs are scope and platform. Astro covers only the Apple App Store, runs only on macOS 14 or later, and doesn't include sales or download analytics. If you ship on Google Play or work from a Windows machine, you'll need something else.

Choose Astro if you're an Apple-only developer who wants a focused, fast tool and doesn't want to count keywords against a plan limit.

RespectASO

RespectASO is the newest of the four and takes an unusual approach: the core app is free and open source under AGPL-3.0, runs natively on your Mac, and requires no account. The developer says it collects no telemetry and keeps your research data on your Mac.

The free version is surprisingly complete. You get keyword research across 175 App Store storefronts, difficulty scores, competitor tracking with ranking history, a country opportunity finder that shows where your app has the best chance, scheduled rank refreshes, and CSV export, with no limits on apps or searches.

RespectASO Pro adds AI automation. It can research up to 1,000 keywords in the background across several countries, turn a seed keyword into a full ASO strategy, and generate metadata that it checks against App Store rules and revises until it passes. Pro also includes an MCP server, so you can run keyword research from Claude Desktop, Cursor, or another MCP-compatible assistant. You bring your own LLM API keys or run a model locally on your Mac.

Pro is sold as a one-time payment for a fixed period: €90 for 12 months or €45 for 3 months, excluding tax, and it doesn't renew automatically. That suits developers who only do focused ASO work around launches and big updates.

The trade-offs: it's App Store only, it's newer and less proven than the others, and the Pro AI features add LLM costs if you use a paid API.

Choose RespectASO if you want serious keyword research for free, value privacy and open source, or want AI-assisted ASO without another subscription.

Appfigures

Appfigures started as an app analytics service and grew into a full ASO and market-intelligence platform. The free plan connects up to five of your apps for sales, downloads, and reviews reporting, but it includes no keyword tracking. ASO starts on the paid plans.

Monitor costs $44.99/month, or $35.99/month billed annually, and tracks 100 keywords with daily rank updates. Optimize costs $149.99/month ($119.99/month annually) and raises the limit to 500 keywords. Higher tiers add competitor tracking and faster rank updates, and the platform also offers AI keyword suggestions. Optimize comes with a free trial that doesn't need a credit card, and you move to the free plan if you don't upgrade.

The appeal is breadth. Appfigures covers both the App Store and Google Play in a web dashboard, so it works from any computer and for any team member. Having ASO data next to your downloads and revenue also makes it easier to see whether a keyword change actually produced installs.

The downside for indie developers is cost per keyword. A 100-keyword cap fills up quickly once you track several apps or localizations, and the jump to 500 keywords is steep.

Choose Appfigures if you want one web dashboard for ASO, sales, and reviews, or you publish on Google Play too.

AppTweak

AppTweak is built for professional growth teams. Its web platform covers the App Store and Google Play with keyword research, competitor metadata, ratings and reviews analysis, and app page previews on every plan.

The Essential plan costs €79/month (€949/year) for 500 keywords. Grow at €249/month is where AppTweak pulls ahead of cheaper tools: it adds estimated organic installs per keyword, keyword impact analysis, long-tail and trending keywords, featuring history, ASO impact reports, and automated alerts. Grow Plus (€499/month) raises limits and extends history to 24 months, and Enterprise adds an ASO Agent, dedicated account management, and consulting. Every self-serve plan has a 7-day free trial. AppTweak is also an official Apple Ads partner, and it sells a separate campaign management product for Apple Ads.

For a solo developer, that's usually more tool and more cost than you need. For a studio managing a portfolio of apps, or a team spending on Apple Ads, the extra data can pay for itself.

Choose AppTweak if ASO is a team job at your company and you need install estimates, market trends, and reporting you can share with stakeholders.

Which ASO Tool Should You Use?

Use Astro if you have one or several Apple-only apps and want unlimited keyword tracking in a native Mac app for about $9 a month.

Use RespectASO if you're launching your first app, don't want another subscription yet, or want to run ASO research through an AI assistant.

Use Appfigures if you want ASO and app analytics in one place, or need Google Play coverage without enterprise pricing.

Use AppTweak if you're a growth team, agency, or studio that needs install estimates, trend data, and Apple Ads tools.

A free tip before you pay for anything: Apple's own Apple Ads keyword planning shows search popularity for App Store keywords, and App Store Connect analytics shows how many impressions come from search. Neither replaces a proper tracking tool, but together they tell you whether ASO is worth the investment for your app.

Final Verdict

Astro is the best value for most indie Apple developers. Unlimited apps and keywords, clean daily tracking, and competitor keyword extraction for $108 a year are hard to beat, as long as you only publish on Apple's stores.

RespectASO is the best free option, and its non-renewing Pro plan makes it the most flexible choice for developers who do ASO in bursts.

Appfigures is the best all-in-one choice when you want keyword tracking alongside downloads, revenue, and reviews, or need Google Play support.

AppTweak is the best choice for teams, with the deepest data of the four and pricing to match.

My practical recommendation: start with RespectASO's free version to learn which keywords matter for your app. If you find yourself tracking dozens of keywords across several apps every week, Astro's flat price is the easiest upgrade.

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Note: Features and prices are current as of September 2026. ASO tools change plans and limits often, and AppTweak's prices are listed in euros. Verify current pricing and features on each developer's official site before buying.

Disclosure: This post contains an affiliate link to Astro. If you buy through it, Apps.Deals may earn a commission at no extra cost to you.