apilenss 0.1.6

API Lens Python SDK with OpenTelemetry-based ingest forwarding

API Lens Python SDK

Production-ready Python ingest client for API Lens with OpenTelemetry integration.

⚠️ Breaking Change in v0.1.6: Both project_slug and app_id are now required for all ingest paths. Make sure both match the same project in your dashboard.

Framework support matrix

Framework	Integration Module	Integration Type	Client Type
FastAPI	apilens.fastapi	ASGI Middleware	AsyncIO
Starlette	apilens.starlette	ASGI Middleware	AsyncIO
Django REST Framework	apilens.django	Django Middleware	Threading
Django Ninja	apilens.django	Django Middleware	Threading
Flask	apilens.flask	WSGI Wrapper	Threading
Litestar	apilens.litestar	Plugin Protocol	AsyncIO
BlackSheep	apilens.blacksheep	ASGI Middleware	AsyncIO

What this SDK includes

• batched + retrying ingest client (ApiLensClient)
• OpenTelemetry span exporter (apilens.otel) for teams already on OTel
• first-class framework integrations listed above
• automatic request/response payload sampling (size-limited)

Install

pip install apilenss

With framework support:

pip install 'apilenss[all]'
# or only one
pip install 'apilenss[fastapi]'
pip install 'apilenss[flask]'

Local development install (from repo):

pip install ./sdks/python
pip install './sdks/python[all]'

Quick start (manual capture)

from apilens import ApiLensClient, ApiLensConfig

client = ApiLensClient(
    ApiLensConfig(
        api_key="your_app_api_key",
        project_slug="your-project-slug",
        base_url="https://api.apilens.ai/api/v1",
        environment="production",
    )
)

client.capture(
    app_id="my-api-service",  # Required: App slug inside that project
    method="GET",
    path="/health",
    status_code=200,
    response_time_ms=12.4,
)

client.shutdown(flush=True)

Getting your Project Slug and App ID

You now need both:

project_slug = "astra"
app_id = "sidecar"

Use the project slug from the project page, and the app slug from the app page in that same project.

FastAPI

No OpenTelemetry instrumentation is required for endpoint + payload monitoring.

from fastapi import FastAPI
from typing import Annotated
from fastapi import Depends, Request
from apilens.fastapi import ApiLensMiddleware, set_consumer

app = FastAPI()

app.add_middleware(
    ApiLensMiddleware,
    api_key="your_app_api_key",      # Required: Your API key
    project_slug="your-project-slug",  # Required: Project slug from dashboard
    app_id="my-api-service",           # Required: App slug inside that project
    base_url="https://api.apilens.ai/api/v1",
    env="production",
    enable_request_logging=True,
    log_request_body=True,
    log_response_body=True,
)

def identify_consumer(request: Request, user_id: Annotated[str, Depends(lambda: "user_123")]):
    set_consumer(request, identifier=user_id, name="Demo User", group="starter")

app.router.dependencies.append(Depends(identify_consumer))

@app.get("/v1/orders")
def list_orders():
    return {"ok": True}

Environment Variables (Recommended):

import os
from fastapi import FastAPI
from apilens.fastapi import ApiLensMiddleware

app = FastAPI()

app.add_middleware(
    ApiLensMiddleware,
    api_key=os.getenv("APILENS_API_KEY"),
    project_slug=os.getenv("APILENS_PROJECT_SLUG"),
    app_id=os.getenv("APILENS_APP_ID"),
    base_url=os.getenv("APILENS_BASE_URL", "https://api.apilens.ai/api/v1"),
    env=os.getenv("APILENS_ENVIRONMENT", "production"),
    enable_request_logging=True,
    log_request_body=True,
    log_response_body=True,
)

Starlette

from starlette.applications import Starlette
from apilens import ApiLensClient, ApiLensConfig
from apilens.starlette import instrument_app

app = Starlette()

client = ApiLensClient(
    ApiLensConfig(
        api_key="your_app_api_key",
        project_slug="your-project-slug",
        base_url="https://api.apilens.ai/api/v1",
        environment="production",
    )
)

instrument_app(
    app,
    client,
    project_slug="your-project-slug",
    app_id="your_app_id"
)

Flask

from flask import Flask
from apilens import ApiLensClient, ApiLensConfig
from apilens.flask import instrument_app

app = Flask(__name__)

client = ApiLensClient(
    ApiLensConfig(
        api_key="your_app_api_key",
        project_slug="your-project-slug",
        base_url="https://api.apilens.ai/api/v1",
        environment="production",
    )
)

instrument_app(
    app,
    client,
    project_slug="your-project-slug",
    app_id="your_app_id"
)

@app.get("/v1/invoices")
def invoices():
    return {"ok": True}

Django (DRF + Django Ninja)

Add middleware in Django settings:

MIDDLEWARE = [
    # ...
    "apilens.django.ApiLensDjangoMiddleware",
]

# Required configuration
APILENS_API_KEY = "your_app_api_key"
APILENS_PROJECT_SLUG = "your-project-slug"
APILENS_APP_ID = "your_app_id"
APILENS_BASE_URL = "https://api.apilens.ai/api/v1"
APILENS_ENVIRONMENT = "production"

Litestar

from litestar import Litestar
from apilens import ApiLensClient, ApiLensConfig
from apilens.litestar import ApiLensPlugin

client = ApiLensClient(
    ApiLensConfig(
        api_key="your_app_api_key",
        base_url="https://api.apilens.ai/api/v1",
        environment="production",
    )
)

app = Litestar(
    route_handlers=[],
    plugins=[ApiLensPlugin(
        client=client,
        app_id="your_app_id"  # Required: Your app ID from dashboard
    )]
)

BlackSheep

from blacksheep import Application
from apilens import ApiLensClient, ApiLensConfig
from apilens.blacksheep import instrument_app

app = Application()

client = ApiLensClient(
    ApiLensConfig(
        api_key="your_app_api_key",
        base_url="https://api.apilens.ai/api/v1",
        environment="production",
    )
)

instrument_app(
    app,
    client,
    app_id="your_app_id"  # Required: Your app ID from dashboard
)

Configuration Options

Parameter	Required	Default	Description
api_key	Yes	-	Your API key from API Lens dashboard
project_slug	Yes	-	Your project slug from API Lens dashboard
app_id	Yes	-	Your app slug inside that project
base_url	No	https://api.apilens.ai/api/v1	API Lens ingest endpoint
environment	No	production	Environment name (e.g., production, staging, dev)
enable_request_logging	No	True	Enable request/response logging
log_request_body	No	False	Log request body (up to max size)
log_response_body	No	False	Log response body (up to max size)

Notes

• Default flush interval: 3s
• Default batch size: 200
• Max ingest batch payload sent per request: follows backend limit (<= 1000)
• Call client.shutdown(flush=True) on graceful shutdown

Troubleshooting

422 Unprocessable Entity Error

If you're getting 422 errors, make sure you've included both project_slug and app_id:

# ❌ Old way (will fail)
app.add_middleware(
    ApiLensMiddleware,
    api_key="your_key",
)

# ✅ New way (required since v0.1.6)
app.add_middleware(
    ApiLensMiddleware,
    api_key="your_key",
    project_slug="your-project-slug",
    app_id="your_app_id",
)

Finding Your Project Slug and App ID

1. Log in to API Lens Dashboard
2. Open your project and copy the project slug
3. Open the app inside that project and copy the app slug

Data Not Appearing in Dashboard

1. Verify project_slug is correct
2. Verify app_id is correct for that project
3. Check that api_key is valid
4. Ensure base_url points to the correct endpoint
5. Check application logs for SDK errors
6. Wait up to 30 seconds for data to appear (batching delay)

Migration from v0.1.5 to v0.1.6

Breaking change: project_slug is now required alongside app_id.

Update all middleware/client configurations to include project_slug and app_id:

# Before (v0.1.5)
client = ApiLensClient(ApiLensConfig(
    api_key="...",
))

# After (v0.1.6)
client = ApiLensClient(ApiLensConfig(
    api_key="...",
    project_slug="your-project-slug",
))

client.capture(
    app_id="your_app_id",
    method="GET",
    path="/health",
    # ...
)

Support

• 📧 Email: [e-mail]
• 📖 Documentation: https://apilens.ai/docs
• 🐛 Issues: https://github.com/apilens/apilens/issues