#HashKit

Overview

#HashKit is a fully native Android toolkit for Instagram creators. It brings 8 independent tools into one app: hashtag research, on-device AI captioning, and caption and bio writing. It is live on Google Play with zero ads, zero login and zero personal data collection.

The Problem

Creators juggle several apps and websites to find hashtags, write captions and check character limits, and many of those tools ask for an Instagram login or broad access to the phone's photos. The goal was one fast, private toolkit that needs neither.

What We Built

• Hashtag Search: type a keyword and get Easy, Medium and Hard hashtags ranked by real post-count difficulty, with a Smart Select mixer
• Keyword Hashtags: 30 ready-to-use hashtags from any keyword, instantly
• Photo AI Generator: on-device image labelling suggests a caption and hashtags for any photo, and the photo never leaves the device
• Caption Writer: 100+ curated captions across niches
• Bio Generator: 5 bio templates per niche
• Character Counter: checks captions and bios against Instagram's limits
• Trending Tags: trending hashtags by category, fully offline
• Reels Downloader: paste a public Reel or post link and save it locally

Engineering Highlights

• No broad media permissions. Early builds requested READ_MEDIA_IMAGES. Because the app only ever needs one user-picked photo, it was moved to the Android Photo Picker, which needs no runtime permission at all. That change met Google Play's Photos and Videos policy and resolved an earlier review rejection. The same fix later became our open-source library, PhotoPickerCompat.
• Removed a risky login pattern. The Reels Downloader originally asked users to sign in to Instagram inside an in-app WebView. That is a security anti-pattern and against Instagram's terms, so it was rebuilt as a public-link-only flow: same feature, no login, no session data.
• Privacy-first AI. Photo analysis runs entirely on the device with Google ML Kit Image Labeling, so nothing is uploaded.
• Production build hygiene. R8 minification and resource shrinking keep the release APK small, and a GitHub Actions CI workflow checks every push.

Tech Stack

Java, native Android Views with Material Components, Google ML Kit (on-device), the Android Photo Picker API, Gradle (AGP 8.9) and GitHub Actions CI.

Status

Live on Google Play (com.hashkit.app). The source is open under the MIT licence at github.com/mukeshkumar356/hashkit-android.