ACS Research · Base model endpoint

Base models, served for research.

Direct, token-level access to large language base models, over an OpenAI compatible API. Free for researchers.

We aim to support research in AI safety and interpretability, understanding LLM psychology and personas, cyborgism-style human-AI collaboration, and more.

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What you get

Base models

Raw /v1/completions — no chat template, no instruction tuning, no system prompt.

Token-level access

Top-k logprobs on generated tokens; top-k or full-vocabulary prompt_logprobs on the input.

Activations & steering

Get the residual stream back with a completion, or add your own steering vectors at the layers you choose.

Workbench and API

A browser workbench for quick tests, and an OpenAI-compatible API for the big experiments.

Models

We currently offer:

llama-8b always on
llama-405b needs ~10 min startup
trinity-truebase always on

We're open to adding more models depending on demand.

Getting access

Apply

Fill in the signup form — who you are and what you'd like to work on.

Get approved

We review each application and email you when it's approved.

Create a key

Generate an API key and start querying.

Need base models for your research?

Apply for access with the signup form, or get in touch if you have any questions.

Apply for access infra@acsresearch.org

We are grateful to Coefficient Giving for funding this platform.