Semantic Search with Mighty and Qdrant

Much like Qdrant, the Mighty inference server is written in Rust and promises to offer low latency and high scalability. This brief demo combines Mighty and Qdrant into a simple semantic search service that is efficient, affordable and easy to setup. We will use Rust and our qdrant_client crate for this integration.

Initial setup

For Mighty, start up a docker container with an open port 5050. Just loading the port in a window shows the following:

  "name": "sentence-transformers/all-MiniLM-L6-v2",
  "architectures": [
  "model_type": "bert",
  "max_position_embeddings": 512,
  "labels": null,
  "named_entities": null,
  "image_size": null,
  "source": ""

Note that this uses the MiniLM-L6-v2 model from Hugging Face. As per their website, the model “maps sentences & paragraphs to a 384 dimensional dense vector space and can be used for tasks like clustering or semantic search”. The distance measure to use is cosine similarity.

Verify that mighty works by calling curl https://<address>:5050/sentence-transformer?q=hello+mighty. This will give you a result like (formatted via jq):

    "outputs": [
            ... (381 values skipped)
    "shape": [
    "texts": [
        "Hello mighty"
    "took": 77

For Qdrant, follow our cloud documentation to spin up a free tier. Make sure to retrieve an API key.

Implement model API

For mighty, you will need a way to emit HTTP(S) requests. This version uses the reqwest crate, so add the following to your Cargo.toml’s dependencies section:

reqwest =  { version = "0.11.18", default-features = false, features = ["json", "rustls-tls"] }

Mighty offers a variety of model APIs which will download and cache the model on first use. For semantic search, use the sentence-transformer API (as in the above curl command). The Rust code to make the call is:

use anyhow::anyhow;
use reqwest::Client;
use serde::Deserialize;
use serde_json::Value as JsonValue;

struct EmbeddingsResponse {
    pub outputs: Vec<Vec<f32>>,

pub async fn get_mighty_embedding(
    client: &Client,
    url: &str,
    text: &str
) -> anyhow::Result<Vec<f32>> {
    let response = client.get(url).query(&[("text", text)]).send().await?;

    if !response.status().is_success() {
        return Err(anyhow!(
            "Mighty API returned status code {}",

    let embeddings: EmbeddingsResponse = response.json().await?;
    // ignore multiple embeddings at the moment
    embeddings.get(0).ok_or_else(|| anyhow!("mighty returned empty embedding"))

Note that mighty can return multiple embeddings (if the input is too long to fit the model, it is automatically split).

Create embeddings and run a query

Use this code to create embeddings both for insertion and search. On the Qdrant side, take the embedding and run a query:

use anyhow::anyhow;
use qdrant_client::prelude::*;

pub const SEARCH_LIMIT: u64 = 5;
const COLLECTION_NAME: &str = "mighty";

pub async fn qdrant_search_embeddings(
    qdrant_client: &QdrantClient,
    vector: Vec<f32>,
) -> anyhow::Result<Vec<ScoredPoint>> {
        .search_points(&SearchPoints {
            collection_name: COLLECTION_NAME.to_string(),
            limit: SEARCH_LIMIT,
            with_payload: Some(true.into()),
        .map_err(|err| anyhow!("Failed to search Qdrant: {}", err))

You can convert the ScoredPoints to fit your desired output format.