# ModernBERT
[ModernBERT](https://huggingface.co/papers/2412.13663) is a modernized version of [`BERT`] trained on 2T tokens. It brings many improvements to the original architecture such as rotary positional embeddings to support sequences of up to 8192 tokens, unpadding to avoid wasting compute on padding tokens, GeGLU layers, and alternating attention.
You can find all the original ModernBERT checkpoints under the [ModernBERT](https://huggingface.co/collections/answerdotai/modernbert-67627ad707a4acbf33c41deb) collection.
> [!TIP]
> Click on the ModernBERT models in the right sidebar for more examples of how to apply ModernBERT to different language tasks.
The example below demonstrates how to predict the `[MASK]` token with [`Pipeline`], [`AutoModel`], and from the command line.
```py
import torch
from transformers import pipeline
pipeline = pipeline(
task="fill-mask",
model="answerdotai/ModernBERT-base",
torch_dtype=torch.float16,
device=0
)
pipeline("Plants create [MASK] through a process known as photosynthesis.")
```
```py
import torch
from transformers import AutoModelForMaskedLM, AutoTokenizer
tokenizer = AutoTokenizer.from_pretrained(
"answerdotai/ModernBERT-base",
)
model = AutoModelForMaskedLM.from_pretrained(
"answerdotai/ModernBERT-base",
torch_dtype=torch.float16,
device_map="auto",
attn_implementation="sdpa"
)
inputs = tokenizer("Plants create [MASK] through a process known as photosynthesis.", return_tensors="pt").to("cuda")
with torch.no_grad():
outputs = model(**inputs)
predictions = outputs.logits
masked_index = torch.where(inputs['input_ids'] == tokenizer.mask_token_id)[1]
predicted_token_id = predictions[0, masked_index].argmax(dim=-1)
predicted_token = tokenizer.decode(predicted_token_id)
print(f"The predicted token is: {predicted_token}")
```
```bash
echo -e "Plants create [MASK] through a process known as photosynthesis." | transformers run --task fill-mask --model answerdotai/ModernBERT-base --device 0
```
## ModernBertConfig
[[autodoc]] ModernBertConfig
## ModernBertModel
[[autodoc]] ModernBertModel
- forward
## ModernBertForMaskedLM
[[autodoc]] ModernBertForMaskedLM
- forward
## ModernBertForSequenceClassification
[[autodoc]] ModernBertForSequenceClassification
- forward
## ModernBertForTokenClassification
[[autodoc]] ModernBertForTokenClassification
- forward
## ModernBertForQuestionAnswering
[[autodoc]] ModernBertForQuestionAnswering
- forward
### Usage tips
The ModernBert model can be fine-tuned using the HuggingFace Transformers library with its [official script](https://github.com/huggingface/transformers/blob/main/examples/pytorch/question-answering/run_qa.py) for question-answering tasks.
