OpenLanguageModel (OLM)

OpenLanguageModel is a PyTorch-native library for building, training, teaching, and researching transformer language models. It is designed for people who want the model architecture to stay visible while the training stack stays manageable.

OLM gives you:

• readable transformer components in olm.nn
• implemented model families in olm.models
• local and Hugging Face dataset streams in olm.data
• single-device, single-node multi-GPU DDP/FSDP, AMP, checkpointing, callbacks, and automatic trainer selection in olm.train

Website · Docs · Install · Colab Notebooks · API Reference · Examples · Issues

Most language-model libraries either hide the architecture behind configuration, or make you rebuild the whole training path from scratch. OLM sits in the middle: every block is an ordinary torch.nn.Module, but data loading, optimization, mixed precision, single-node multi-GPU training, checkpointing, and logging are already wired into a clean path.

That makes it useful for:

• students learning how language models are assembled and trained
• researchers running ablations on attention, norms, feed-forward layers, and residual structure
• practitioners who want existing PyTorch workflows without a hidden runtime

Model code in OLM is meant to read like the architecture it represents. For example, the Llama 3 block is built from RMSNorm, grouped-query attention, SwiGLU, and explicit residual structure:

from olm.nn.structure import Block
from olm.nn.structure.combinators import Residual
from olm.nn.attention import GroupedQueryAttention
from olm.nn.feedforward import SwiGLUFFN
from olm.nn.norms import RMSNorm


class Llama3Block(Block):
    def __init__(
        self,
        embed_dim: int,
        intermediate_size: int,
        num_heads: int,
        num_kv_heads: int,
        max_seq_len: int,
        dropout: float,
        rope_theta: float,
    ):
        super().__init__([
            Residual(Block([
                RMSNorm(embed_dim, eps=1e-5),
                GroupedQueryAttention(
                    embed_dim,
                    num_heads,
                    num_kv_heads,
                    max_seq_len,
                    dropout=dropout,
                    rope_theta=rope_theta,
                    use_bias=False,
                ),
            ])),
            Residual(Block([
                RMSNorm(embed_dim, eps=1e-5),
                SwiGLUFFN(
                    embed_dim,
                    hidden_dim=intermediate_size,
                    dropout=dropout,
                    bias=False,
                ),
            ])),
        ])

Source: src/olm/models/meta/llama3.py

You can keep the model and optimizer as normal PyTorch objects while OLM handles the training loop details:

import torch

from olm.data.datasets import DataLoader, FineWebEduDataset
from olm.data.tokenization import HFTokenizer
from olm.models.openai import GPT2Model
from olm.train import AutoTrainer
from olm.train.optim import AdamW

tokenizer = HFTokenizer("gpt2")
dataset = FineWebEduDataset(tokenizer, context_length=1024, streaming=True)
loader = DataLoader(dataset, batch_size=8, num_workers=4)

model = GPT2Model(
    vocab_size=tokenizer.vocab_size,
    embed_dim=768,
    num_layers=12,
    num_heads=12,
    max_seq_len=1024,
)

trainer = AutoTrainer(
    model,
    AdamW,
    loader,
    device="auto",
    context_length=1024,
    learning_rate=3e-4,
    grad_accum_steps=8,
)
trainer.train(epochs=1, max_steps=1000)

AutoTrainer chooses between CPU, single-GPU, and single-node multi-GPU DDP/FSDP paths based on the hardware and model. You can still use Trainer, DDPTrainer, or FSDPTrainer directly when you want explicit control.

OLM includes named presets and configurable base classes for common transformer families:

See docs/api.md for the generated API reference and examples/ for training scripts.

Use Python 3.10, 3.11, or 3.12.

git clone https://github.com/openlanguagemodel/openlanguagemodel.git
cd openlanguagemodel
pip install -e .

For development:

pip install -e ".[dev]"
pytest tests

Optional extras:

pip install -e ".[wandb]"  # Weights & Biases logging
pip install -e ".[docs]"   # documentation tooling

See docs/installation.md for dependency and release-build details.

• Install from docs/installation.md
• Start with docs/getting-started.md
• Review architecture concepts in docs/architecture.md
• Run guided Colabs from docs/colab-notebooks.md
• Train from examples in examples/
• Use docs/datasets-and-training.md for data, trainer, AutoTrainer, callbacks, and checkpointing
• Use docs/api.md when you need exact signatures and source-defined methods
• Read docs/release-v2.2.0.md for the v2.2 release notes

OLM v2.2 is the stabilization and release-readiness pass: tied output embeddings by default, model-family smoke coverage, AutoTrainer, streaming datasets, AMP, checkpointing, single-node DDP/FSDP paths, clearer installation docs, and a stronger generated API reference. Multi-node training remains a v4 roadmap item.

@software{openlanguagemodel2026,
  title = {OpenLanguageModel},
  author = {Tavish Mankash and Vardhaman Kalloli and Keshava Prasad},
  year = {2026},
  url = {https://github.com/openlanguagemodel/openlanguagemodel}
}

MIT. See LICENSE.