join39.org

What It Is

Join39 is a personal AI agent platform built for the “agentic web.” Users can sign in with Google and create Agent Facts with a username, personality, profile, and skills, allowing their agents—once authorized—to enter social spaces, games, debates, experiments, and agent-to-agent interaction scenarios. It is not a traditional single-purpose AI tool; it is closer to an open identity layer, Agent Store, and multi-agent experience platform.

Core Capabilities

In terms of AI capabilities, Join39 relies on agent profiles and personality prompts to generate responses that fit a given role. In the documentation examples, the experience layer calls OpenAI, with the model listed as gpt-5-mini. Developers can build Apps that let agents call external REST APIs during conversations via OpenAI function calling. They can also build Experiences, where an external platform actively asks an agent to post, take action, or participate in a game. The platform also provides service registration, event webhooks, HMAC signatures, a TypeScript SDK, and an MCP-compatible runtime, giving it relatively strong integration capabilities.

Pricing and Limits

The site discloses two plans: Basic and Early Access Pioneer. Basic includes agent creation, Agent Facts, chat, and joining experiences. Pioneer includes OpenClaw deployment, Digital Ocean hosting, security, and built-in AI models, but it requires joining a waitlist and no price is provided. The technical limits are relatively clear: App tools can be called up to 3 times per turn, with a 10-second timeout and a 2,000-character response limit; Experience responses are capped at 500 tokens, rate-limited to once every 5 seconds per agent per experience, and can support daily action caps.

Pros and Cons

Its strengths are its open positioning, detailed documentation, and clearly defined paths for Apps, Experiences, and Platform Integration. Any language can integrate via HTTPS/REST. Agent Facts are public and portable, making the platform suitable for multi-agent experiments and community ecosystems. The downsides are limited commercialization information and the fact that the hosted offering is still in early access. Details on AI model choices, stability SLAs, content moderation, and privacy compliance are also insufficient. There is no clear indication of a Chinese interface, Chinese documentation, or Chinese-language customer support.

Who It’s For and Access from China

Join39 is suitable for developers, researchers, classroom projects, game/community experiment teams, and early adopters who want to create a digital representative for themselves. It is less suitable for teams that need mature enterprise-grade permissions, audit features, and localized support. The main text does not provide information on access from China. Domain availability, Google login, OpenAI dependencies, and overseas hosting may all affect the actual user experience; payment methods are also not disclosed. For domestic alternatives in China, platforms such as 扣子, Dify, and FastGPT may be more localized options.