FastChat-T5-11B

High-Performance Open Chatbot Based on T5

What is FastChat-T5-11B?

FastChat-T5-11B is an 11-billion-parameter encoder-decoder language model, based on the T5 architecture, fine-tuned for instruction-following dialogue and conversational tasks. Released as part of the FastChat project, it provides an open, efficient, and scalable solution for real-time chat, summarization, Q&A, and reasoning, with a focus on fast inference and easy local deployment.

Its T5-style format enables a strong mix of understanding and generation, ideal for projects that need balanced input-output control, low latency, and high-quality responses.

Key Features of FastChat-T5-11B

11B Parameters, T5-Style Sequence Model

Encoder-decoder transformer architecture ensures rich contextual input processing and coherent output generation.

Instruction-Tuned for Natural Dialogue

Trained to follow user prompts for summarization, answering, rewriting, reasoning, and task execution in a chat format.

Optimized for Fast, Local Inference

Despite its size, FastChat-T5-11B is optimized for inference performance, supporting CPU and GPU use with quantized versions.

Open-Source & Customizable

Available with training details and permissive license, can be fine-tuned or integrated into private tools and services.

General-Purpose NLP Capability

Performs well across summarization, translation, classification, and chat, thanks to T5's flexible architecture.

Compatible with FastChat Ecosystem

Integrates easily with open-source FastChat servers, UI, and inference APIs for deployment and testing.

Use Cases of FastChat-T5-11B

Build smart, responsive, and aligned AI chat tools that handle context and instruction-heavy queries with ease.

Summarize long documents, reports, or customer communications efficiently using T5-style generation.

Incorporate into workflows for classification, rephrasing, Q&A, and structured information extraction.

Use for model comparison, prompt alignment, and training-based experimentation in academic settings.

Deploy secure, fast, instruction-following chat models in web apps, portals, or knowledge bases.

FastChat-T5-11B

vs

Similar Instruction Models

Feature	FastChat-T5-3B	Dolly-V2-12B	GPT4All-13B	FastChat-T5-11B
Parameters	3B	12B	13B	11B
Architecture	T5	Decoder (Pythia)	Decoder (LLaMA)	T5 (Encoder-Decoder)
Instruction Tuning	Moderate	Strong	Strong	✅ Strong
Inference Speed	Very Fast	Moderate	Moderate	✅ Optimized for Speed
Best Use Case	Mobile AI Agents	Enterprise Chat	Local Private AI	Scalable Fast Chat + NLP