A series of large language models (LLMs) developed in Japan by Preferred Networks (PFN). What sets it apart is that it is built entirely from scratch rather than fine-tuned from an overseas model, giving it real strength in understanding and generating Japanese. The lineup includes the flagship Prime family (available via chat and API), the lightweight Lite family, and PLaMo Translate, which specializes in Japanese translation. Some models are released under PFN’s own “PLaMo Community License,” so individuals and small-to-medium businesses can use them commercially under certain conditions. In June 2026, the latest PLaMo 3.0 Prime was officially released with long-context support and improved reasoning performance.
Key Features
- A from-scratch Japanese LLM: Not a derivative of an overseas model — PFN handles everything from pre-training onward. Training that prioritizes Japanese-language data gives it an edge in Japanese reading comprehension and generation
- The Prime family (flagship): The main model, available through both chat and API. The latest PLaMo 3.0 Prime adds long-context support and stronger reasoning, aimed at business workloads and agent use cases
- The lightweight Lite family: A compact model that runs comfortably on edge devices and on-premises environments. You can pick between Prime and Lite depending on your use case and available compute
- PLaMo Translate, built for Japanese: A translation service that claims world-class Japanese translation quality. Alongside the browser version, there are desktop apps for Mac and Windows, with support for translating PDF, Word, and PowerPoint files
- PLaMo Community License: Some models are published under PFN’s own community license, allowing commercial use by individuals and small-to-medium businesses under certain conditions. It is also easy to work with for research and evaluation
- On-premises deployment available: Beyond the cloud API, PFN accepts inquiries about on-premises deployment for organizations that cannot send data outside their walls
Pricing
Pricing is split between PLaMo itself (chat and API) and PLaMo Translate.
PLaMo API (Standard plan, usage-based)
| Model | Input | Output |
|---|---|---|
| PLaMo 3.0 Prime | ¥60 per 1M tokens | ¥250 per 1M tokens |
The chat version is free to use. For the API, there is the usage-based Standard plan plus a separate plan for companies that build AI services on top of it.
PLaMo Translate
| Plan | Monthly price | Key features |
|---|---|---|
| Free | ¥0 | 200,000 characters/month of browser translation, 50,000 characters/month of text translation, 1 file translation/month |
| Lite | ¥980 (¥1,078 incl. tax) | Everything in Free, plus unlimited-page browser translation, 1M characters/month of text translation, 20 file translations/month |
| Pro | ¥2,580 (¥2,838 incl. tax) | 5M characters/month of text translation, 80 file translations/month, unlimited glossaries |
| Lite Team | ¥1,980 per person (¥2,178 incl. tax) | 2M characters/month of text translation per person, 25 file-translation points/month |
| Pro Team | ¥3,580 per person (¥3,938 incl. tax) | 10M characters/month of text translation per person, 100 file-translation points/month |
| Enterprise | Contact sales | For large organizations. Supports invoice billing and more |
The team plans assume multiple users and support member management and consolidated billing.
Pricing reflects information as of August 21, 2026. Check the official site and the PLaMo Translate pricing page for current rates.
Pros and Cons
✅ Pros
- A from-scratch domestic model with genuine strength in natural, accurate Japanese
- Low per-token API pricing, which keeps the cost of Japanese-language processing down
- Plenty of free entry points — the chat version, the PLaMo Translate Free plan
- PLaMo Translate goes as far as file translation (PDF / Word / PowerPoint) through its desktop app
- Community-licensed models exist, giving you options for local evaluation and on-premises use
⚠️ Cons
- On general English-language tasks and cutting-edge multimodal features, it can fall short of overseas flagships like the GPT and Claude families
- The ecosystem (third-party integrations, community knowledge) is still small compared with the major overseas players
- Commercial use under the Community License comes with conditions, and larger companies need a separate agreement
- The model and plan lineup is still evolving, so it pays to verify current details
Comparison with Similar Services
| Criterion | PLaMo | tsuzumi | Sarashina | ChatGPT |
|---|---|---|---|---|
| Provider | Preferred Networks | NTT | SB Intuitions (SoftBank) | OpenAI |
| Country of development | Japan | Japan | Japan | United States |
| Distinguishing trait | Built from scratch, specialized Japanese translation | Lightweight, power-efficient | Japanese-focused domestic LLM | Versatility, breadth of ecosystem |
| Entry point for individuals | Free chat, Translate Free plan | Mostly enterprise-oriented | Mostly enterprise-oriented | Free plan available |
| API available | Yes (usage-based) | Yes (enterprise) | Yes | Yes |
Among Japanese LLMs, PLaMo is one of the easiest to get started with, precisely because it offers entry points (chat and translation) that individuals can try for free.
Who It’s For
- Anyone who wants high-quality, low-cost Japanese translation and text processing
- Companies and organizations that need a domestically developed LLM for confidentiality reasons
- Business users who translate PDF and Office files as part of daily work
- Developers who want to evaluate or run an LLM locally or on-premises
- Anyone who wants a Japanese-specialized model in their toolkit rather than relying solely on overseas models
Summary
PLaMo is a Japanese LLM series that has sharpened its Japanese-language performance through the rare approach of building from scratch. It offers a wide range of entry points — chat, API, and translation — and PLaMo Translate in particular is genuinely practical for individuals thanks to its free plan and desktop app. It is not trying to match the leading overseas models on sheer versatility, but if you value Japanese-language quality and domestic development, it is a strong option. Start with the free chat or the PLaMo Translate Free plan.