Comparison

Atomic KB vs Celestis

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

Head to head
About

Atomic KB

Features
Read full description

Atomic is a client for your self-hosted Atomic knowledge base. It connects to your own server to give you mobile access to your notes, saved articles, and semantic search. Save any web page from Safari or any browser using the Share Extension — Atomic automatically extracts the article content, generates embeddings, and connects it to your existing knowledge. Features: - Browse, create, and edit markdown notes - Save web articles from any app via the Share Extension - Semantic and hybrid search across your knowledge base - Hierarchical tag browsing - Offline support with local caching - Connect via QR code or manual setup Requires a self-hosted Atomic server. Learn more at https://github.com/kenforthewin/atomic

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

Screenshots

Atomic KB4 screens
Celestis4 screens

Verdict

The call

The clearest difference is update cadence: Celestis at every 2 weeks against Atomic KB's every 2 months. Atomic KB's advantage is iOS requirement (15.0 vs 26.0). On price, ads, in-app purchases 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. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Atomic KB ships an update every 2 months, Celestis every 2 weeks. Both last shipped on September 18, 2026.

Scorecard2 real differences · 8 level
Atomic KB versus Celestis: the parameters behind the verdict, then further details
ParameterAtomic KBCelestis
PriceFreeFree
Rating—5.0 (4 ratings) — better
Positive reviews—100.0% of reviews
Number of ratings—4 — better
Update frequencyEvery 2 monthsEvery 2 weeks — better
AdsNoNo
In-app purchasesNoNo
Monetization—Free
DevicesiPhone, iPadiPhone, iPad
Requires iOS15.0 — better26.0
Further details — not scored
Size6 MB3.0 GB
Age rating4+12+
DeveloperFoldspace Labs LLCCelestis Ai Inc

In-app purchases

None

Atomic KB

No in-app purchases

None

Celestis

No in-app purchases

Questions

Is Atomic KB free?
Atomic KB is free to download, with no in-app purchases.
Is Celestis free?
Celestis is free to download, with no in-app purchases.
Do Atomic KB or Celestis have ads?
Neither Atomic KB nor Celestis shows ads.
Which is updated more often, Atomic KB or Celestis?
Atomic KB ships an update every 2 months, and Celestis every 2 weeks. Most recently, Atomic KB was updated on September 18, 2026 and Celestis on September 18, 2026.

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