AI Models You Can Use on Your Kindle
You can't install apps on a Kindle, so your AI options have always been limited. With companion.ink, you get access to all the major models through one e-reader-friendly interface.
Here's what's available and what each one is good at.
OpenAI Models
GPT-5.4
OpenAI's latest and most capable. Best choice for complex reasoning, creative writing, and anything that needs real depth.
GPT-5.4 also supports thinking modes. You can choose how much the model "thinks" before responding:
- GPT-5.4. Standard mode. Fast, great for most things.
- GPT-5.4 (thinking). Light reasoning. Good balance of speed and depth.
- GPT-5.4 (more thinking). More deliberate. Better for complex questions.
- GPT-5.4 (max thinking). Full reasoning. Best for hard problems, analysis, and anything where you want the model to really work through it.
More thinking = better answers for complex questions, but uses more credits and takes longer.
- Best for: Long-form writing, complex analysis, research, creative tasks
- Speed: Fast in standard mode, slower with thinking enabled
- Credit usage: Moderate in standard mode, higher with thinking
GPT-5 Mini
Lighter and faster. Good for everyday questions where you don't need the full power of 5.4.
- Best for: Quick questions, simple explanations, casual chat
- Speed: Fast
- Credit usage: Low. Your monthly credits go much further.
GPT-4.1
Solid model with good instruction-following. A step below GPT-5.4 but very reliable.
- Best for: Structured tasks, precise instructions, technical questions
- Speed: Fast
- Credit usage: Low-moderate
GPT-4o
Older but still capable. Good all-rounder if you want to stretch your credits.
- Best for: General chat, summaries, Q&A
- Speed: Fast
- Credit usage: Low
Anthropic Models
Claude Opus 4.6
Anthropic's most powerful. Excels at nuanced, thoughtful responses and long-form content.
Also supports thinking modes:
Opus 4.6. Standard mode.
Opus 4.6 (more thinking). Enhanced reasoning for complex tasks.
Best for: In-depth analysis, book discussions, nuanced writing, long conversations
Speed: Moderate
Credit usage: Highest. Use this when you really need depth.
Claude Sonnet 4.6
The sweet spot. Fast, capable, cost-effective. Probably the best default for most people.
Supports thinking modes:
Sonnet 4.6. Standard mode. Fast and cheap.
Sonnet 4.6 (more thinking). More deliberate reasoning.
Sonnet 4.6 (max thinking). Full reasoning mode.
Best for: Day-to-day chat, reading companion questions, summaries
Speed: Fast in standard mode
Credit usage: Low. Great for staying within your monthly credits.
How to Choose
Not sure which model to use? Quick guide:
| Use Case | Recommended Model |
|---|---|
| Quick questions while reading | Sonnet 4.6 or GPT-5 Mini |
| Deep discussion about a book | Opus 4.6 or GPT-5.4 (thinking) |
| Summarising a chapter | Sonnet 4.6 or GPT-5.4 |
| Complex research question | GPT-5.4 (max thinking) or Opus 4.6 (more thinking) |
| Creative writing | GPT-5.4 or Opus 4.6 |
| Stretching your budget | GPT-5 Mini or GPT-4o |
How Credits Work
companion.ink is $5/month, which includes $4 of API credits. Different models cost different amounts per message:
- Cheapest (GPT-5 Mini, GPT-4o). Hundreds of messages per month.
- Mid-range (GPT-4.1, Sonnet 4.6, GPT-5.4 standard). 100-200+ messages per month.
- Premium (GPT-5.4 with thinking, Opus 4.6). Fewer messages, but much better responses for complex questions.
You can switch any time, so a common approach: use Sonnet 4.6 or GPT-5 Mini for quick questions, switch to GPT-5.4 with thinking or Opus 4.6 when you need real depth.
Switching Models on Your Kindle
Simple:
- Open companion.ink on your Kindle
- Tap the settings icon
- Pick your model (and thinking level if applicable)
- Next message uses the new one
Chat history is preserved when you switch.
We Keep Adding Models
When OpenAI or Anthropic release something new, it's usually available on companion.ink within days.
Want to try them? Get started with companion.ink. Or check out the setup guide if you're new.