Comparison

Celestis vs Index

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Celestis

This AI assistant empowers professionals with private, on-device intelligence for document analysis and knowledge retrieval. It offers offline capabilities, custom AI models built from your data, and supports various AI providers for ultimate flexibility and data sovereignty.

Highlights
  • On-device AI with Apple Intelligence
  • Offline AI capabilities
  • Private Capsules for custom AI models
  • Support for multiple AI providers
  • Near 100% accurate, sourceable answers
  • Document ingestion from various formats
Features
Read full description

Celestis: Private AI for Your Documents Your Knowledge. Your Data. Your AI. Celestis is an intelligent AI platform built for professionals who demand accuracy, privacy, and the freedom to work anywhere. Whether you're on a factory floor, aboard an aircraft, in a maintenance bay, or off the grid, Celestis brings full AI power to the edge and even completely offline. Celestis doesn't just chat. It understands your documents, learns from your knowledge, and delivers near 100% accurate, sourceable answers powered by an Adaptive-RAG engine. AI to the Edge: Offline. Anywhere. Always. Celestis Mobile supports on-device AI powered by Apple intelligence, letting you take your AI-powered knowledge completely offline. Get instant, accurate answers no matter where you are. - Maintenance technicians accessing service manuals in remote facilities - Factory workers querying procedures on the shop floor - Airline crews referencing documentation at 35,000 feet - Field engineers troubleshooting without a data connection Your knowledge travels with you. No Wi-Fi. No cell signal. No problem. Private Capsules: Your Data, Your Environment Capsules are the heart of Celestis. Each one is a self-contained, domain-specific AI built from your own documents. Private Capsules go further, running entirely in your environment for total data sovereignty. - Upload PDFs, Word docs, spreadsheets, presentations, CSVs, images, Markdown, and more - Combine Capsules into Pods for cross-domain AI with intelligent routing - Add custom instructions and guardrails per Capsule or Pod - Schedule automatic re-ingestion to keep your AI current Celestis never trains on your data. Your documents are never shared or retained beyond what you authorize. Choose Your AI Provider: Zero Vendor Lock-In Celestis ships ready to use with leading AI models, no API key required or bring your own. - Built-in: Celestis, ChatGPT, Claude, Grok - Open source: Any OpenAI-compatible endpoint - Local LLMs: Ollama and any locally-run model for complete privacy with zero cloud dependency Mix and match providers per Capsule. What Sets Celestis Apart - Near 100% Accuracy: Adaptive-RAG blends semantic and keyword search so every answer is precise and sourceable - On-device AI with Apple Intelligence - Powered by Apple Silicon in the cloud and green datacenters - Reader Mode: Read documents while asking questions in a seamless split view - Super AI: Augment Celestis with your Capsules to create a personalized AI that knows your domain - Simple Credit Pricing: No token math. Credits per action type, in the app or via API - Replicas Marketplace: Publish your Capsules, earn credits when others use your knowledge, creators keep 70% - Connectors: Source knowledge from Gmail, Google Drive, Notion, Slack, or any REST API Key Features - Chat with Celestis AI, always free to start - Domain-specific AI Capsules built from your documents - Offline AI Bundles for full AI access with no internet - Private Capsules running entirely in your environment - Audio Conversations and Text-to-Speech - Bring Your Own Model: ChatGPT, Claude, Grok, Ollama, and more - Capsule Collections with intelligent cross-domain routing - Reader Mode for side-by-side document reading and querying - Image generation and transformation - Live search and deep research - Connectors that connect to your MCP Servers, providing limitless data sources - Team collaboration with shared Capsule pools - Full API access for custom integrations - Analytics for Capsule performance, credit spend, and replica earnings Terms of Service: https://celestis.ai/terms-of-service Privacy Policy: https://celestis.ai/privacy-policy

About

Index

Features
Read full description

Save anything. Think with everything. Index is a personal knowledge workspace for the context you do not want to lose. Share a link, note, or document from your iPhone, and it becomes part of a calm, organized brain you can return to later. ASK YOUR BRAIN Discuss complex ideas across everything you have saved. Index grounds answers in your own context and links citations back to each source. CAPTURE WITHOUT BREAKING FOCUS Use the iOS share sheet to save useful links, selected text, files, and quick notes in seconds. TURN LINKS INTO CONTEXT Index extracts readable page content, creates a concise summary, and keeps your own note beside it. STAY IN CONTROL Your account syncs across devices. Delete individual items and conversations whenever you want, or permanently delete your account and its captures, files, chats, and feedback from inside the app. Built for founders, researchers, and knowledge workers who want less friction between finding something useful and thinking with it. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://index-legal.vercel.app/privacy

Screenshots

Celestis4 screens
Index4 screens

Verdict

The call

The clearest difference is in-app purchases: Celestis at none against Index's 2. Celestis also leads on ratings volume (4 vs 1). Index's advantage is iOS requirement (17.0 vs 26.0). On price, rating, ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Index sells 2 in-app purchases, starting at $9.99 per month. Celestis asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 5.0 for Celestis against 5.0 for Index. Both are backed by a comparable volume of ratings — 4 and 1 respectively.

Scorecard3 real differences · 7 level
Celestis versus Index: the parameters behind the verdict, then further details
ParameterCelestisIndex
PriceFreeFree
Rating5.0 (4 ratings)5.0 (1 ratings)
Positive reviews100.0% of reviews—
Number of ratings4 — better1
Update frequencyEvery 2 weeks—
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree—
DevicesiPhone, iPadiPhone, iPad
Requires iOS26.017.0 — better
Further details — not scored
Size3.0 GB19 MB
Age rating12+4+
DeveloperCelestis Ai IncSunset Capital, llc

In-app purchases

None

Celestis

No in-app purchases

2 purchases

Index

Subscriptions2
  • Index Pro Monthly$9.991 Month
  • Index Pro Annual7 Days trial$79.991 Year

Questions

Is Celestis free?
Celestis is free to download, with no in-app purchases.
Is Index free?
Index is free to download, with in-app purchases available.
Which has better reviews, Celestis or Index?
Celestis and Index are both rated 5.0 out of 5 on the App Store, from 4 and 1 ratings respectively.
Do Celestis or Index have ads?
Neither Celestis nor Index shows ads.

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