Comparison

Prompt Planter vs Celestis

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

Head to head
About

Prompt Planter

Features
Read full description

Write, test, and grow your prompts. Track versions of your AI prompts with diff view, version restore, and {{template}} variables - now synced across iPhone, iPad, and Mac. Prompt Planter is a calm, private home for the AI prompts you actually want to keep. If you reuse the same prompts across different AI assistants, you know the pain: the good version is buried somewhere in a chat history, and you end up rewriting it from scratch. Prompt Planter lets you save your best prompts, improve them over time, and grab the right one in seconds. THE SAME LIBRARY ON EVERY DEVICE - Syncs automatically over iCloud. Start a draft on your iPhone and finish it on your iPad or Mac. - Nothing to set up. If you are signed in to iCloud, everything is already there when you open the app. - You can check the sync status any time in Settings. GROW YOUR PROMPTS - Keep prompts, project instructions, skills, CLAUDE.md files, and system prompts in one library. - Every prompt has a full version history. Save a new version whenever you tweak it, with a short note on what changed. - See exactly what changed between versions, highlighted with + and - marks. - Restore any past version at any time. Restoring adds a new revision, so your history is never lost. - Rate each version and record how it actually performed, so you always know which one works best. ONE PROMPT, TUNED FOR EVERY AI - Create variants of the same prompt for different models. - Tag prompts by AI and by purpose so you can find exactly what you need. Give AI tags a color to tell them apart at a glance. - Duplicate a whole prompt, version history included, when you want to take it in a different direction. CAPTURE IDEAS FAST - Jot a quick draft, then save it to your library as a new prompt, a new version, or a new variant. - One-tap copy to the clipboard, ready to paste into any chat. - Write {{name}} in a prompt body and a fill-in form appears when you copy it or send it to Drafts. FIND WHAT YOU ARE LOOKING FOR - Pin your go-to prompts to the top. - Mark favorites and filter by kind, AI, or purpose. - Search covers change notes and result notes too, not just the prompt body, so you can find that one insight you wrote down. - Your sort order and filters are remembered between launches. YOUR DATA STAYS YOURS - No account, no sign-in, no ads, no tracking. - Sync uses your own iCloud private database. The developer cannot see its contents. - Not using iCloud? Everything stays on your device and every feature still works. - Export and import your whole library as a JSON file for backup or moving between devices. FULLY BILINGUAL - Use the app in English or Japanese, switchable anytime. Prompt Planter is designed to be quiet, fast, and out of your way, so your prompts can grow alongside your work.

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

Prompt Planter4 screens
Celestis4 screens

Verdict

The call

The clearest difference is update cadence: Celestis at every 2 weeks against Prompt Planter's monthly. 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

Prompt Planter ships an update monthly, Celestis every 2 weeks. The most recent releases landed on October 8, 2026 and October 23, 2026 respectively.

Scorecard1 real difference · 9 level
Prompt Planter versus Celestis: the parameters behind the verdict, then further details
ParameterPrompt PlanterCelestis
PriceFreeFree
Rating—5.0 (4 ratings) — better
Positive reviews—100.0% of reviews
Number of ratings—4 — better
Update frequencyMonthlyEvery 2 weeks — better
AdsNoNo
In-app purchasesNoNo
Monetization—Free
DevicesiPhone, iPadiPhone, iPad
Requires iOS26.026.0
Further details — not scored
Size3 MB3.0 GB
Age rating4+12+
DeveloperYusuke NakashimaCelestis Ai Inc

In-app purchases

None

Prompt Planter

No in-app purchases

None

Celestis

No in-app purchases

Questions

Is Prompt Planter free?
Prompt Planter is free to download, with no in-app purchases.
Is Celestis free?
Celestis is free to download, with no in-app purchases.
Do Prompt Planter or Celestis have ads?
Neither Prompt Planter nor Celestis shows ads.
Which is updated more often, Prompt Planter or Celestis?
Prompt Planter ships an update monthly, and Celestis every 2 weeks. Most recently, Prompt Planter was updated on October 8, 2026 and Celestis on October 23, 2026.

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