SumizAI vs LastChat

What LastChat is

LastChat is a feature-rich AI assistant application for Android, built as a fork of the popular RikkaHub application, modified and developed using the latest models - Claude 4.5 Opus, GPT Codex, and Gemini 3 Pro. The application is fully open source, released under the AGPL-3.0 license, meaning anyone can review its source code, modify it for their own needs, and verify how queries and responses are processed. As a fork of an existing project, LastChat builds on RikkaHub's established codebase while introducing its own modifications and enhancements developed with the assistance of the AI models mentioned above.

Key features and functionality

As a mobile application for Android, LastChat offers a native chat interface optimized for the phone screen, unlike many competing solutions available only as web pages requiring a browser. Inheriting RikkaHub's codebase, the app retains the core mechanisms for managing conversations, chat history, and AI model access configuration typical of mature open-source chat clients. The AGPL-3.0 license, a stronger form of open source license than the more common MIT, requires that any code modifications made publicly available (for instance, as a network service) also remain open source, protecting the project against commercial parties closing off their forks.

Who it's for

LastChat is aimed primarily at Android users looking for an open-source alternative to commercial chat applications, wanting full visibility into the code responsible for processing their conversations. Open source enthusiasts following the development of projects like RikkaHub and its forks appreciate being able to use an application developed in a spirit of transparency and community collaboration. People interested in the practical application of the latest AI models - Claude 4.5 Opus, GPT Codex, Gemini 3 Pro - to mobile software development find LastChat an interesting real-world example of this approach. Android developers who want to modify or extend the chat client's functionality for their own needs make use of the full source code's availability under the AGPL-3.0 license.

Use cases

In everyday use, LastChat serves as a mobile client for conversations with AI models, accessible directly from the phone screen without needing to open a browser and log into separate websites for every provider. People who prefer open-source applications over closed software choose LastChat as a deliberate alternative to commercial chat clients available in the Google Play Store. Developers interested in the mechanics of forking and developing existing open-source projects can analyze LastChat's code as a case study in modifying an existing codebase with AI model assistance. Users who value the AGPL-3.0 license for ethical reasons, supporting projects that guarantee lasting code openness, deliberately choose LastChat among other RikkaHub forks.

Pricing and business model

LastChat is free and open source under the AGPL-3.0 license, meaning there are no fees whatsoever for downloading and using the application. As an open-source project, the business model rests on developer community involvement rather than traditional subscription revenue. It's worth noting that while the app itself is free, using AI models such as Claude or GPT typically requires the user's own API keys from the respective providers, generating separate costs independent of the LastChat app itself, consistent with the typical model of open-source chat clients connecting to external APIs.

Comparison with SumizAI

LastChat and SumizAI represent different approaches to accessing multiple AI models. LastChat is an open-source mobile application for Android requiring its own configuration of access to individual models via API keys. SumizAI, by contrast, is a ready-made platform aggregating multiple AI providers in one place, accessible from a browser, without needing to manage access keys for each model separately. Android users who value open code and want full control over configuration may choose LastChat, while people looking for a ready, integrated solution without needing technical configuration naturally lean toward platforms like SumizAI.

AI notes on a mobile device

LastChat users holding intensive conversations with multiple AI models on a mobile device often export the most important fragments of those conversations as ai notes, building a knowledge archive accessible offline, regardless of which model answered a given question. Because LastChat is a mobile app, many users use it to quickly jot down ideas as ai notes during the day, when access to a computer is limited, and then move those ai notes into a more elaborate knowledge management system once back at a desk. The openness of the code also lets advanced users customize how such ai notes are exported and organized to their own preferences, something closed commercial apps don't offer. Because LastChat runs locally on the device, conversation history and related ai notes remain accessible even without a constant internet connection, which can matter while traveling or in areas with poor signal.

What SumizAI is

A note-taking application built around a conversation with an AI model. You ask a question, the answer streams back, and the answers worth keeping become Markdown notes — filed into a vault that is a folder on your own disk.

A vault is a directory holding base.md, a generated table of contents up to six levels deep, and a notes/ folder with one .md file per note. Before a note is written it is checked against the ones already there, so the fourth note about the same idea gets merged instead of added. Links between notes are ordinary Markdown links to files that exist.

The model is never ours: you bring your own API key to one of seven providers — Anthropic, OpenAI, Gemini, Groq, OpenRouter, a local Ollama or your own server — and pay that provider directly. A question sends the table of contents plus at most five relevant notes within a 24,000-character budget, and the app shows you which five it used.

Every answer kept this way becomes one of these ai notes, ready to search again months later without hunting back through old chats.

Side by side

Where they differ

• LastChat is a place to have the conversation. SumizAI is not a chatbot — the conversation is the input, not the product. What comes out of it is a .md file with a title, a place in base.md and a duplicate check against the notes already in the vault. If you only want to talk to a model, you do not need SumizAI.
• LastChat is open source (AGPL-3.0), and SumizAI is not. If reading the source is what decides it for you, that is a real argument for LastChat. The guarantee SumizAI offers instead is structural rather than legal: the notes are Markdown files in a folder you chose, so they open in any editor whether or not the application is running.
• AlternativeTo's description of LastChat does not mention Markdown, so check what format your notes end up in before you fill it up. SumizAI writes standard .md files to a folder you picked, and an unpaid account can still export all of them.

Which one to pick