Contextual AI Reranker Models with Weaviate
v1.34.0Weaviate's integration with Contextual AI's APIs allows you to access their models' capabilities directly from Weaviate.
Configure a Weaviate collection to use a Contextual AI reranker model, and Weaviate will use the specified model and your Contextual AI API key to rerank search results.
This two-step process involves Weaviate first performing a search and then reranking the results using the specified model.

Requirements
Weaviate configuration
Your Weaviate instance must be configured with the Contextual AI reranker integration (reranker-contextualai) module.
For Weaviate Cloud (WCD) users
This integration is enabled by default on Weaviate Cloud (WCD) serverless instances.
For self-hosted users
- Check the cluster metadata to verify if the module is enabled.
- Follow the how-to configure modules guide to enable the module in Weaviate.
API credentials
You must provide a valid Contextual AI API key to Weaviate for this integration. Go to Contextual AI to sign up and obtain an API key.
Provide the API key to Weaviate using one of the following methods:
- Set the
CONTEXTUAL_API_KEYenvironment variable that is available to Weaviate. - Provide the API key at runtime, as shown in the examples below.
If a snippet doesn't work or you have feedback, please open a GitHub issue.
import weaviate
from weaviate.classes.init import Auth
import os
# Recommended: save sensitive data as environment variables
contextual_key = os.getenv("CONTEXTUAL_API_KEY")
headers = {
"X-ContextualAI-Api-Key": contextual_key,
}
client = weaviate.connect_to_weaviate_cloud(
cluster_url=weaviate_url, # `weaviate_url`: your Weaviate URL
auth_credentials=Auth.api_key(weaviate_key), # `weaviate_key`: your Weaviate API key
headers=headers
)
# Work with Weaviate
client.close()
Configure the reranker
v1.25.23, v1.26.8 and v1.27.1A collection's reranker model integration configuration is mutable from v1.25.23, v1.26.8 and v1.27.1. See this section for details on how to update the collection configuration.
Configure a Weaviate collection to use a Contextual AI reranker model as follows:
If a snippet doesn't work or you have feedback, please open a GitHub issue.
from weaviate.classes.config import Configure
client.collections.create(
"DemoCollection",
reranker_config=Configure.Reranker.contextualai()
# Additional parameters not shown
)
Reranker parameters
Configure the reranker behavior, including the model to use, through the following parameters:
If a snippet doesn't work or you have feedback, please open a GitHub issue.
from weaviate.classes.config import Configure
client.collections.create(
"DemoCollection",
reranker_config=Configure.Reranker.contextualai(
model="ctxl-rerank-v2-instruct-multilingual",
instruction="Prioritize internal sales documents over market analysis reports. More recent documents should be weighted higher.",
top_n=5
)
# Additional parameters not shown
)
The default model is used if no model is specified.
For further details on model parameters, see the Contextual AI API documentation.
Header parameters
You can provide the API key as well as some optional parameters at runtime through additional headers in the request. The following headers are available:
X-ContextualAI-Api-Key: The Contextual AI API key.
Any additional headers provided at runtime will override the existing Weaviate configuration.
Provide the headers as shown in the API credentials examples above.
Reranking query
Once the reranker is configured, Weaviate performs reranking operations using the specified Contextual AI model.
More specifically, Weaviate performs an initial search, then reranks the results using the specified model.
Any search in Weaviate can be combined with a reranker to perform reranking operations.

If a snippet doesn't work or you have feedback, please open a GitHub issue.
from weaviate.classes.query import Rerank
collection = client.collections.use("DemoCollection")
response = collection.query.near_text(
query="A holiday film", # The model provider integration will automatically vectorize the query
limit=2,
rerank=Rerank(
prop="title", # The property to rerank on
query="A melodic holiday film" # If not provided, the original query will be used
)
)
for obj in response.objects:
print(obj.properties["title"])
Available models
ctxl-rerank-v1-instructctxl-rerank-v2-instruct-multilingual-minictxl-rerank-v2-instruct-multilingual(default)
Further resources
Other integrations
Code examples
Once the integrations are configured at the collection, the data management and search operations in Weaviate work identically to any other collection. See the following model-agnostic examples:
- The How-to: Manage collections and How-to: Manage objects guides show how to perform data operations (i.e. create, read, update, delete collections and objects within them).
- The How-to: Query & Search guides show how to perform search operations (i.e. vector, keyword, hybrid) as well as retrieval augmented generation.
References
- Contextual AI Rerank API documentation
Questions and feedback
If you have any questions or feedback, let us know in the user forum.
