@mastra/fastembed

@mastra/fastembed

Local embedding model integration for Mastra, powered by ONNX Runtime.

This package is a maintained fork of fastembed-js (now archived). The upstream source has been vendored directly into this package so that @mastra/fastembed no longer depends on the unmaintained fastembed npm package.

Installation

pnpm add @mastra/fastembed

Usage

Default (AI SDK v3)

import { Memory } from '@mastra/memory';
import { fastembed } from '@mastra/fastembed';

const memory = new Memory({
  // ... other memory options
  embedder: fastembed,
});

Available Models

import { fastembed } from '@mastra/fastembed';

// Default export (bge-small-en-v1.5 with v3 spec)
const embedder = fastembed;

// Named exports for v3 models
const small = fastembed.small; // bge-small-en-v1.5
const base = fastembed.base; // bge-base-en-v1.5

// V2 models (for AI SDK v5 compatibility)
const smallV2 = fastembed.smallV2;
const baseV2 = fastembed.baseV2;

// Legacy v1 models (for backwards compatibility)
const smallLegacy = fastembed.smallLegacy; // bge-small-en-v1.5 (v1 spec)
const baseLegacy = fastembed.baseLegacy; // bge-base-en-v1.5 (v1 spec)

Direct Usage with AI SDK

import { embed } from 'ai';
import { fastembed } from '@mastra/fastembed';

const result = await embed({
  model: fastembed,
  value: 'Text to embed',
});

console.log(result.embedding); // number[]

Supported Models

Model	Dimensions	Description
bge-small-en-v1.5	384	Fast, default English model
bge-base-en-v1.5	768	Base English model
bge-small-en	384	Fast English model
bge-base-en	768	Base English model
bge-small-zh-v1.5	512	Fast Chinese model
all-MiniLM-L6-v2	384	Sentence Transformer model
multilingual-e5-large	1024	Multilingual model

Attribution

The core embedding engine is forked from fastembed-js by Anush008, licensed under MIT. See LICENSE-fastembed for the original license.