> ## Documentation Index
> Fetch the complete documentation index at: https://praison.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Lazy Imports & Fast Startup
> Optimize import time and memory usage with lazy loading
# Lazy Imports & Fast Startup
PraisonAI Agents v0.5.0+ uses lazy imports to dramatically reduce startup time and memory usage. Heavy dependencies like `litellm`, `requests`, and `chromadb` are only loaded when actually needed.
```python theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
from praisonaiagents import Agent
agent = Agent(name="MyAgent") # litellm loads on first LLM call
agent.start("Hello")
```
The user imports PraisonAI and starts an agent instantly; heavy libraries load only on first use.
```mermaid theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
graph LR
Agent[🤖 Agent] --> Tool[⚡ Lazy Import]
Tool --> Result[🚀 Fast Startup]
classDef agent fill:#8B0000,stroke:#7C90A0,color:#fff
classDef tool fill:#189AB4,stroke:#7C90A0,color:#fff
class Agent agent
class Tool tool
```
## How It Works
```mermaid theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
sequenceDiagram
participant User
participant Agent
participant LazyImportsFast
User->>Agent: Request
Agent->>LazyImportsFast: Process
LazyImportsFast-->>Agent: Result
Agent-->>User: Response
```
## Quick Start
```python theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
from praisonaiagents import Agent
agent = Agent(name="MyAgent") # litellm loads on first LLM call
```
```python theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
import sys
import praisonaiagents
assert "litellm" not in sys.modules
print("Heavy dependencies not loaded at import time")
```
## Performance Benefits
| Metric | Before | After | Improvement |
| ------------ | ------ | ------ | ------------------- |
| Import Time | 820ms | 18ms | **97.8% faster** |
| Memory Usage | 93.3MB | 33.0MB | **64.6% reduction** |
## How It Works
```mermaid theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
sequenceDiagram
participant User
participant Agent
participant Feature as Lazy Imports & Fast Startup
User->>Agent: Request
Agent->>Feature: Process request
Feature-->>Agent: Result
Agent-->>User: Response
```
### Lazy Module Loading
Core modules are loaded on-demand using Python's `__getattr__` mechanism:
```python theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
# These imports are fast - modules loaded lazily
from praisonaiagents import Agent, Session, Memory, Knowledge
# Agent is only fully loaded when you use it
agent = Agent(name="MyAgent") # litellm loaded here
```
### Heavy Dependencies
The following dependencies are NOT loaded at import time:
* **litellm** - Only loaded when LLM calls are made
* **requests** - Only loaded when HTTP calls are needed
* **chromadb** - Only loaded when vector stores are used
* **mem0** - Only loaded when memory features are used
### Training & Vision Module Lazy Loading
Modules affected: `praisonai.train.llm.trainer` (the `TrainModel` class) and `praisonai.upload_vision` (the `UploadVisionModel` class) now use lazy loading to defer heavy ML dependencies.
These modules use a `_lazy_import_*_deps()` helper called from `__init__`, mirroring `train.py` / `train_vision.py` patterns.
**Dependencies deferred:**
* **torch** - CUDA/GPU computation framework
* **transformers** (`TextStreamer`, `TrainingArguments`) - Hugging Face transformers
* **unsloth** (`FastLanguageModel`, `FastVisionModel`, `is_bfloat16_supported`, `standardize_sharegpt`, `get_chat_template`) - Fast training optimization
* **trl** (`SFTTrainer`) - Transformer Reinforcement Learning
* **datasets** (`load_dataset`, `concatenate_datasets`) - Dataset loading utilities
* **psutil** (`virtual_memory`) - System memory monitoring
**Impact:** Importing `praisonai.upload_vision` or `praisonai.train.llm.trainer` is now near-instant; CUDA / \~2 GB of ML libs only load when you instantiate `UploadVisionModel(...)` or `TrainModel(...)`.
```python theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
# Fast — no torch/unsloth load
from praisonai.upload_vision import UploadVisionModel
# Heavy deps load here, not at import time
uploader = UploadVisionModel(config_path="config.yaml")
```
ImportError messages now include install hints:
* Vision upload: `pip install torch unsloth`
* Training: `pip install torch transformers unsloth datasets trl psutil`
## Verifying Lazy Imports
You can verify lazy imports are working:
```python theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
import sys
# Import the package
import praisonaiagents
# Check that heavy deps are NOT loaded
assert 'litellm' not in sys.modules
assert 'requests' not in sys.modules
assert 'chromadb' not in sys.modules
# Check training/vision modules are lazy loaded
from praisonai.upload_vision import UploadVisionModel # noqa
assert "torch" not in sys.modules
assert "unsloth" not in sys.modules
print("✓ All heavy dependencies are lazy loaded")
```
## Configuration
Lazy imports are enabled by default. You can check the configuration:
```python theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
from praisonaiagents._config import LAZY_IMPORTS
print(f"Lazy imports enabled: {LAZY_IMPORTS}")
```
## Best Practices
Defer optional modules until a feature is invoked — keeps CLI and server startup fast.
Use `pip install praisonaiagents[memory]` rather than pulling every optional dependency upfront.
Track cold import duration to catch accidental module-level heavy imports in PRs.
Use the lite package when you bring your own LLM client and need minimal footprint.
```python theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
# Good - specific imports
from praisonaiagents import Agent, Task
# Avoid - loads all modules
from praisonaiagents import *
```
## Measuring Performance
Use the built-in benchmarks to measure import time:
```python theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}}
import time
start = time.perf_counter()
import praisonaiagents
end = time.perf_counter()
print(f"Import time: {(end - start) * 1000:.1f}ms")
```
## Related
Import time and memory metrics
Minimal BYO-LLM subpackage