ASO keyword workflow with Astro

Most indie App Store Optimization advice tells you to "pick good keywords" and stops there. The hard part is not knowing what good means. It is building a loop you can run every few weeks without it eating a whole day.

The workflow below uses Astro, the macOS ASO tool from tryastro.app. The goal is not to game the store. It is to stop guessing, fit the constraints Apple gives you, and let rank data tell you what to change next.

The constraint you cannot ignore

Apple gives you a 100-character keyword field in App Store Connect. Terms are comma-separated with no spaces between them, and spaces only separate words inside a phrase. Every word in your app name, subtitle, and primary category is already indexed, so repeating it in the keyword field wastes characters. Plurals of a word you already included count as duplicates and add nothing.

That 100 characters is the entire vocabulary the search algorithm pulls from beyond your title and subtitle. So the work is not "find keywords." It is "pack 100 characters with the terms that actually move your rank, and drop the ones that do not."

This is where a lot of solo developers stall. They brainstorm a list, paste it in, submit, and never look again. Astro exists to make the looking-again part cheap.

What Astro gives you

Astro is a native macOS app (macOS 14 and up) that pulls keyword popularity data from Apple Search Ads and computes a difficulty score for ranking in the top 10 for each term. It tracks your app's rank for keywords daily across more than 60 App Store regions, shows position history as charts, and can surface the keywords your competitors already rank for so you can borrow the ones that fit.

The two numbers that matter for the workflow below are popularity (how many people search the term) and difficulty (how hard it is to climb into the visible results). A term with high popularity and high difficulty is a long fight. A term with middling popularity and low difficulty is usually where a solo app wins first.

The workflow

Run this roughly every two to three weeks, or after any meaningful release. More often than that and you are reading noise.

1. Pull the keywords your app already ranks for. Astro already knows which terms your app appears for. Open the app, look at the current ranking list, and note the terms where you sit in the top 20 but not the top 5. Those are your cheapest wins. A small metadata change can nudge them into the visible results.

2. Find gaps with competitor keywords. Pick two or three apps that solve a similar problem for a similar audience. Astro can extract the keywords they rank for. Cross-reference those against your own list. Terms they rank for and you do not are candidates, but only if they honestly describe your app. Apple rejects keyword stuffing and irrelevant terms, and a rejection costs you a review cycle.

3. Score every candidate on popularity and difficulty. For each term, look at the popularity-to-difficulty ratio. You are not chasing the most popular term. You are chasing terms where you can actually reach the top 10 with your download volume and rating count. A solo app with a few hundred ratings will usually lose the fight for "fitness" and win the fight for "minimal habit tracker."

4. Pack the 100 characters. Build your new keyword string in a text editor first. Strip every word that already appears in your app name or subtitle. Drop plurals of singulars you already have. Join terms with commas, no spaces between terms, spaces only inside phrases. Count the characters. If you are over 100, cut the lowest-ratio term first.

5. Update in App Store Connect and submit. Paste the string into the keyword field for one locale at a time. If your app is English-only, start there. Astro tracks more than 60 regions, so once you have a winning set in your home store, you can localize it store by store rather than redoing research from scratch.

6. Wait, then read the rank movement. Give it 10 to 14 days. Astro will show the position change for each tracked term. A term that climbed is working. A term that fell or did not move after two weeks is a candidate to swap out next cycle.

A worked example of the 100-character pack

Say you built a minimal habit tracker. Your app name is "Streak" and your subtitle is "build habits gently." Those words are already indexed, so none of them go in the keyword field.

A first draft of keywords might be:

habit,tracker,daily,routine,goal,reminder,streak,checklist,build,gentle

Now apply the rules. "Streak," "habit," and "gentle" appear in your name or subtitle, so cut them. "Build" is in the subtitle, cut it. What remains:

tracker,daily,routine,goal,reminder,checklist

That is 41 characters. You have 59 left, which is room for more specific phrases people actually search. Astro's popularity data might surface "daily routine planner" and "goal tracker free" as terms with decent popularity and low difficulty for your app's size. Add the ones that honestly fit:

tracker,daily,routine,goal,reminder,checklist,daily routine planner,goal tracker free

That is 81 characters. You have room for one or two more. This is the part the workflow replaces guesswork: you pick the next terms from Astro's scored list, not from a brainstorm, and each one earns its 100-character slot with data.

What this workflow does not do

It does not write your app name or subtitle, which carry more search weight than the keyword field. It does not fix screenshots, ratings, or conversion. Keywords get you into the results. Screenshots and ratings get you the download. If your keyword rank is climbing and installs are not, the problem is on the product page, not in the keyword field.

It also does not work for Android or the Google Play Store, which use a different indexing model. Astro is Apple-only.

The short version

• The 100-character keyword field is a packing problem, not a brainstorming problem. Every character does a job or loses one.
• Run the loop every two to three weeks: pull current rank, borrow competitor terms, score on popularity and difficulty, repack, submit, wait, read the movement.
• Win the low-difficulty terms first. A solo app climbs into the top 10 for specific phrases long before it wins the broad ones.

If you want app store optimization as part of the full path from Expo app to launch, Mobile Development with Expo covers metadata, keywords, screenshots, and submission.