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    Neuronpedia is an open source interpretability platform.
    Explore, visualize, and steer the internals of AI models.
    Latest Post - August 2026
    Introducing: interp-engine 🚀🔎
    A Fast, Standardized, and Easy-to-Use Interpretability Engine
    Newsletter
    Gurnee et al.
    Jacobian Lens
    Revealing a Global Workspace in Language Models
    Fraser-Taliente, Kantamneni, Ong et al.
    Natural Language Autoencoders
    Translate a Model's Internal Thoughts Into Text
    Lu et al.
    Assistant Axis
    Monitor & Stabilize the Character of an LLM
    Multi-Org
    Circuit Tracer
    Trace a Model's Internal Reasoning Steps
    Google Deepmind
    Gemma Scope 2
    SAEs and Transcoders for Gemma 3
    MIT Technology ReviewAnthropicGoogle DeepMindVentureBeatOpenMOSS, Fudan UniversityEleutherAIApollo Research
    Releases and Models
    Browse five+ terabytes of activations, explanations, and metadata.
    Neuronpedia supports probes, latents/features, custom vectors, concepts, and more.

    Releases

    Models

    GoLLeM-v5-128M Muon v1
    GoLLeM-v5-128M Muon v1custom

    Jump To

    Jump to Source/SAE
    Jump to Feature
    INDEX
    Jump to Random
    Graph
    Visualize and trace the internal reasoning steps of a model with custom prompts, pioneered by Anthropic's circuit tracing papers.
    Attribution graph example with Dallas gemma-2-2b
    Steer
    Modify model behavior by steering its activations using latents or custom vectors. Steering supports instruct (chat) and reasoning models, and has fully customizable temperature, strength, seed, etc.
    Steering example with a cat feature
    Search
    Search over 50,000,000 latents/vectors, either by semantic similarity to explanation text, or by running custom text via inference through a model to find top matches.

    Search via Inference

    Run Example Search
    API + Libraries
    Neuronpedia hosts the world's first interpretability API (March 2024) - and all functionality is available by API or Python/TypeScript libraries. Most endpoints have an OpenAPI spec and interactive docs.
    Steering example with a cat feature
    Inspect
    Go in depth on each probe/latent/feature with top activations, top logits, activation density, and live inference testing. All dashboards have unique links, can be compiled into sharable lists, and supports IFrame embedding, as demonstrated here.
    Who We Are
    Neuronpedia was created by Johnny Lin, an ex-Apple engineer who previously founded a privacy startup. Neuronpedia is supported by Decode Research, Open Philanthropy, the Long Term Future Fund, AISTOF, Anthropic, Manifund, and others.
    Get Involved
    Citation
    @misc{neuronpedia,
    title = {Neuronpedia: Interactive Reference and Tooling for Analyzing Neural Networks},
    year = {2023},
    note = {Software available from neuronpedia.org},
    url = {https://www.neuronpedia.org},
    author = {Lin, Johnny}
}