by jinaai
Open source · 17k downloads · 18 likes
The *Jina Code Embeddings 0.5b* model is a lightweight yet high-performance solution designed for code search and retrieval. It excels in various tasks, including text-to-code conversion, finding similar code snippets, and generating code completions, while supporting over 15 programming languages. With tailored instruction prefixes, it adapts seamlessly to different needs, whether answering technical questions or serving educational applications. What sets it apart is its ability to generate dense 896-dimensional embeddings (reducible to 64 without significant performance loss), striking an optimal balance between efficiency and accuracy. Versatile in scope, it covers domains like web development, AI, and data science while remaining accessible for rapid deployment. Ideal for code search tools, development assistants, or technical QA systems, it stands as a compact and robust alternative to larger models.
jina-code-embeddings is an embedding model for code retrieval.
The model supports various types of code retrieval (text-to-code, code-to-code, code-to-text, code-to-completion) and technical question answering across 15+ programming languages.
Built on Qwen/Qwen2.5-Coder-0.5B, jina-code-embeddings-0.5b features:
Summary of features:
| Feature | Jina Code Embeddings 0.5B |
|---|---|
| Base Model | Qwen2.5-Coder-0.5B |
| Supported Tasks | nl2code, code2code, code2nl, code2completion, qa |
| Model DType | BFloat 16 |
| Max Sequence Length | 32768 |
| Embedding Vector Dimension | 896 |
| Matryoshka dimensions | 64, 128, 256, 512, 896 |
| Pooling Strategy | Last-token pooling |
| Attention Mechanism | FlashAttention2 |
The following Python packages are required:
transformers>=4.53.0torch>=2.7.1sentence-transformers interface, install this package as well.# !pip install transformers>=4.53.0 torch>=2.7.1
import torch
import torch.nn.functional as F
from transformers import AutoModel, AutoTokenizer
INSTRUCTION_CONFIG = {
"nl2code": {
"query": "Find the most relevant code snippet given the following query:\n",
"passage": "Candidate code snippet:\n"
},
"qa": {
"query": "Find the most relevant answer given the following question:\n",
"passage": "Candidate answer:\n"
},
"code2code": {
"query": "Find an equivalent code snippet given the following code snippet:\n",
"passage": "Candidate code snippet:\n"
},
"code2nl": {
"query": "Find the most relevant comment given the following code snippet:\n",
"passage": "Candidate comment:\n"
},
"code2completion": {
"query": "Find the most relevant completion given the following start of code snippet:\n",
"passage": "Candidate completion:\n"
}
}
MAX_LENGTH = 8192
def cosine_similarity(x,y):
x = F.normalize(x, p=2, dim=1)
y = F.normalize(y, p=2, dim=1)
return x @ y.T
def last_token_pool(last_hidden_states, attention_mask):
left_padding = (attention_mask[:, -1].sum() == attention_mask.shape[0])
if left_padding:
return last_hidden_states[:, -1]
else:
sequence_lengths = attention_mask.sum(dim=1) - 1
batch_size = last_hidden_states.shape[0]
return last_hidden_states[torch.arange(batch_size, device=last_hidden_states.device), sequence_lengths]
def add_instruction(instruction, query):
return f'{instruction}{query}'
# The queries and documents to embed
queries = [
add_instruction(INSTRUCTION_CONFIG["nl2code"]["query"], "print hello world in python"),
add_instruction(INSTRUCTION_CONFIG["nl2code"]["query"], "initialize array of 5 zeros in c++")
]
documents = [
add_instruction(INSTRUCTION_CONFIG["nl2code"]["passage"], "print('Hello World!')"),
add_instruction(INSTRUCTION_CONFIG["nl2code"]["passage"], "int arr[5] = {0, 0, 0, 0, 0};")
]
all_inputs = queries + documents
tokenizer = AutoTokenizer.from_pretrained('jinaai/jina-code-embeddings-0.5b')
model = AutoModel.from_pretrained('jinaai/jina-code-embeddings-0.5b')
batch_dict = tokenizer(
all_inputs,
padding=True,
truncation=True,
max_length=MAX_LENGTH,
return_tensors="pt",
)
batch_dict.to(model.device)
outputs = model(**batch_dict)
embeddings = last_token_pool(outputs.last_hidden_state, batch_dict['attention_mask'])
query_embeddings = embeddings[:2]
passage_embeddings = embeddings[2:]
# Compute the (cosine) similarity between the query and document embeddings
scores = cosine_similarity(query_embeddings, passage_embeddings)
print(scores)
# tensor([[0.8168, 0.1236],
# [0.1204, 0.5525]], grad_fn=<MmBackward0>)
# !pip install sentence_transformers>=5.0.0 torch>=2.7.1
import torch
from sentence_transformers import SentenceTransformer
# Load the model
model = SentenceTransformer(
"jinaai/jina-code-embeddings-0.5b",
model_kwargs={
"torch_dtype": torch.bfloat16,
"attn_implementation": "flash_attention_2",
"device_map": "cuda"
},
tokenizer_kwargs={"padding_side": "left"},
)
# The queries and documents to embed
queries = [
"print hello world in python",
"initialize array of 5 zeros in c++"
]
documents = [
"print('Hello World!')",
"int arr[5] = {0, 0, 0, 0, 0};"
]
query_embeddings = model.encode(queries, prompt_name="nl2code_query")
document_embeddings = model.encode(documents, prompt_name="nl2code_document")
# Compute the (cosine) similarity between the query and document embeddings
similarity = model.similarity(query_embeddings, document_embeddings)
print(similarity)
# tensor([[0.8169, 0.1214],
# [0.1190, 0.5500]])
import torch
import torch.nn.functional as F
from vllm import LLM
INSTRUCTION_CONFIG = {
"nl2code": {
"query": "Find the most relevant code snippet given the following query:\n",
"passage": "Candidate code snippet:\n"
},
"qa": {
"query": "Find the most relevant answer given the following question:\n",
"passage": "Candidate answer:\n"
},
"code2code": {
"query": "Find an equivalent code snippet given the following code snippet:\n",
"passage": "Candidate code snippet:\n"
},
"code2nl": {
"query": "Find the most relevant comment given the following code snippet:\n",
"passage": "Candidate comment:\n"
},
"code2completion": {
"query": "Find the most relevant completion given the following start of code snippet:\n",
"passage": "Candidate completion:\n"
}
}
def add_instruction(instruction, text):
return f"{instruction}{text}"
def cosine_similarity(x, y):
x = F.normalize(x, p=2, dim=1)
y = F.normalize(y, p=2, dim=1)
return x @ y.T
# Build the queries and documents
queries = [
add_instruction(INSTRUCTION_CONFIG["nl2code"]["query"], "print hello world in python"),
add_instruction(INSTRUCTION_CONFIG["nl2code"]["query"], "initialize array of 5 zeros in c++"),
]
documents = [
add_instruction(INSTRUCTION_CONFIG["nl2code"]["passage"], "print('Hello World!')"),
add_instruction(INSTRUCTION_CONFIG["nl2code"]["passage"], "int arr[5] = {0, 0, 0, 0, 0};"),
]
all_inputs = queries + documents
# vLLM embedding model
llm = LLM(
model="jinaai/jina-code-embeddings-0.5b",
task="embed"
)
# Encode with vLLM
outputs = llm.encode(all_inputs)
# Collect embeddings into a single tensor
emb_list = []
for out in outputs:
vec = out.outputs.data.detach()
emb_list.append(vec)
embeddings = torch.stack(emb_list, dim=0)
# Split into query and passage embeddings
n_q = len(queries)
query_embeddings = embeddings[:n_q]
passage_embeddings = embeddings[n_q:]
# Cosine similarity matrix (queries x documents)
scores = cosine_similarity(query_embeddings, passage_embeddings)
print(scores)
# tensor([[0.8171, 0.1230],
# [0.1207, 0.5513]])
Please refer to our technical report of jina-code-embeddings for training details and benchmarks. If you find it useful in your research, please cite the following paper:
@misc{kryvosheieva2025efficientcodeembeddingscode,
title={Efficient Code Embeddings from Code Generation Models},
author={Daria Kryvosheieva and Saba Sturua and Michael Günther and Scott Martens and Han Xiao},
year={2025},
eprint={2508.21290},
archivePrefix={arXiv},
primaryClass={cs.CL},
url={https://arxiv.org/abs/2508.21290},
}
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