LlamaIndex projects depend on a Python package set that wires the framework, integrations, and data readers into the interpreter that runs the application. Installing it inside a project virtual environment keeps those packages away from the operating-system Python and gives notebooks, scripts, and services the same import path.
The current llama-index package on PyPI requires Python 3.10 or newer and lower than Python 4. The quickstart package installs llama-index-core plus the default OpenAI LLM and embedding integrations and the file reader package; narrower llama-index-* packages can be installed later when a project uses a different provider.
A package metadata check and a tiny import smoke test prove that the active interpreter sees the installed distribution without calling an external model API. Configure provider credentials separately before running query engines, agents, or workflows that use hosted LLMs.
$ python3 --version Python 3.14.4
LlamaIndex currently requires Python 3.10 or newer and lower than Python 4. If python3 is missing or too old, install a current Python runtime before creating the project environment.
$ mkdir -p ~/llamaindex-project
$ cd ~/llamaindex-project
$ python3 -m venv .venv
The command normally returns no output when the environment is created.
Related: Create a Python virtual environment
$ source .venv/bin/activate
On Windows PowerShell, activate the same environment with .\.venv\Scripts\Activate.ps1.
Related: Activate a Python virtual environment
(.venv) $ command -v python /home/analyst/llamaindex-project/.venv/bin/python
(.venv) $ python -m pip install --upgrade pip Requirement already satisfied: pip in ./.venv/lib/python3.14/site-packages (25.1.1) Collecting pip ##### snipped ##### Successfully installed pip-26.1.2
Use python -m pip from the activated environment instead of a standalone pip command when several Python runtimes are installed.
(.venv) $ python -m pip install --upgrade llama-index Collecting llama-index Collecting llama-index-core<0.15.0,>=0.14.23 (from llama-index) Collecting llama-index-embeddings-openai<0.7,>=0.6.0 (from llama-index) Collecting llama-index-llms-openai<0.8,>=0.7.0 (from llama-index) ##### snipped ##### Successfully installed llama-index-0.14.23 llama-index-core-0.14.23 llama-index-embeddings-openai-0.6.0 llama-index-llms-openai-0.7.9
The exact dependency versions change as PyPI releases move. The important signal is that llama-index and llama-index-core install into the active virtual environment.
(.venv) $ python -m pip show llama-index Name: llama-index Version: 0.14.23 Summary: Interface between LLMs and your data Home-page: https://llamaindex.ai ##### snipped ##### Location: /home/analyst/llamaindex-project/.venv/lib/python3.14/site-packages Requires: llama-index-core, llama-index-embeddings-openai, llama-index-llms-openai, nltk
(.venv) $ python -m pip check No broken requirements found.
If pip check reports a conflict, recreate the virtual environment or pin compatible package versions before using the environment for application code.
(.venv) $ python - <<'PY'
from importlib.metadata import version
from llama_index.core import Document
doc = Document(text="LlamaIndex is installed.")
print(f"llama-index: {version('llama-index')}")
print(f"document text: {doc.text}")
PY
llama-index: 0.14.23
document text: LlamaIndex is installed.