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Nandan Das
Nandan Das

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I Built an AI That Auto-Replies to Your Instagram DMs (No Login Required)

#android #kotlin #ai #opensource

I Built an AI That Auto-Replies to Your Instagram DMs (No Login Required)

Managing Instagram DMs is a full-time job. Whether you are a small business owner, a content creator, or just someone who gets too many messages, you have probably missed important replies because you could not keep up.

So I built InstaReply Bot: an open-source Android app that watches your Instagram notifications and replies with AI-generated messages. Automatically. In the background. Without your Instagram password.

Here is how it works, why I built it, and what I learned.

The Problem

Instagram does not have an official API for sending DMs to personal accounts. Most automation tools either:

  1. Require your login credentials (security risk)
  2. Use fragile web scraping (breaks when Instagram updates)
  3. Need the screen on (not practical for background automation)

I wanted something different: a solution that works entirely through Android notification system, with zero credential sharing.

The Solution: Notification Listener + AI

InstaReply Bot uses Android Notification Listener API to read incoming Instagram DM notifications. When a new message arrives, the app:

  1. Extracts the sender name and message text from the notification
  2. Matches the message against user-defined rules (keyword patterns, regex, specific contacts)
  3. Generates a reply using an AI provider (Groq, Gemini, OpenRouter, or any OpenAI-compatible API)
  4. Sends the reply through Instagram own notification Reply action, exactly like tapping Reply in your notification shade, but automated

The key insight: Instagram notification already includes a Reply action. InstaReply Bot just automates clicking that button.

Why No Login Is Needed

Most Instagram bots need your username and password. That is a dealbreaker for me because:

  • Security risk: Credentials stored on someone else server
  • Account ban: Instagram actively detects and bans automation accounts
  • Privacy: I do not want to trust anyone with my Instagram session

InstaReply Bot never touches your Instagram credentials. It works with Android notification system, a system-level API that Google designed for exactly this kind of use case.

Free AI Models Included

I did not want cost to be a barrier, so InstaReply Bot supports free AI providers:

Groq (Free Tier)

  • openai/gpt-oss-20b: Fast, great for quick replies
  • llama-3.3-70b-versatile: Better conversational quality
  • qwen/qwen3.6-27b: Multilingual support

OpenCode Zen (Free Tier)

  • opencode/deepseek-v4-flash-free: Lightweight, fast
  • opencode/mimo-v2.5-free: Context-aware responses

Google Gemini (Free Tier Available)

  • gemini-3.6-flash: Google latest

No credit card required for any of these. You can also use paid providers like OpenRouter, NVIDIA, or OpenAI if you want more power.

Technical Architecture

The app is built with Kotlin and follows modern Android development practices:

com.instareply/
  ai/          AI providers (Gemini, Groq, OpenRouter, OpenAI, Zen, Custom)
  service/     Notification listener, Accessibility fallback, ReplyEngine
  data/        Room database (Rules, Contacts, Reply logs)
  ui/          Main dashboard, Settings, Rule editor
  util/        Preferences manager, Provider configuration
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Key decisions:

  • Room Database for local storage: rules, contacts, and reply logs stay on your device
  • OkHttp for API calls: lightweight and reliable
  • Material Design: native Android look and feel
  • Kotlin Coroutines: efficient background processing

The One-Reply Guarantee

One of the hardest problems was ensuring exactly one reply per message. Instagram sometimes re-posts notifications while the AI is still generating, which could cause duplicate replies.

InstaReply Bot solves this with three layers:

  1. 60-second deduplication: Same sender + message text within 60 seconds is ignored
  2. Persisted log check: Successful replies are stored for 10 minutes (survives app restarts)
  3. Send discipline: The AI text is typed once, Send is clicked at most once

What I Learned

1. Notification APIs Are Powerful

Android Notification Listener API is underutilized. It is a legitimate system API that can transform how apps interact with notifications, no hacking required.

2. Free AI Is Real

Groq and OpenCode Zen offer genuinely useful free tiers. For a personal auto-reply bot, free models work perfectly.

3. Deduplication Is Hard

What seems simple: reply to each message once, is actually complex when notifications can arrive multiple times and the AI takes a few seconds to respond.

4. Users Care About Privacy

Every person I showed this to asked: Does it need my password? When I say no, the reaction is always relief. Privacy-first design matters.

Try It

The app is open source and available on GitHub:

github.com/nandandas2407-web/InstaReplyBot

  1. Download the APK from Releases: https://github.com/nandandas2407-web/InstaReplyBot/releases/latest
  2. Grant Notification Access
  3. Configure a free AI provider (Groq takes 2 minutes)
  4. Create your reply rules

What Is Next

  • Support for Instagram Story mentions
  • Multi-language reply templates
  • Webhook integration for business workflows
  • iOS support (if there is interest)

Open to Contributions

This is a side project, but I am open to contributions. If you want to help:

  • Check the issue tracker for open issues
  • Read the contributing guidelines
  • Submit a PR: I review within 24 hours

Built with Kotlin for Android. Free AI models included. No Instagram login required.

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