smello 0.3.0

Capture outgoing HTTP requests and inspect them in a local web dashboard

Smello

Capture outgoing HTTP requests from your Python code and browse them in a local web dashboard — including gRPC calls made by Google Cloud libraries.

Like Mailpit, but for HTTP requests.

Setup

Install the client SDK and the server:

pip install smello smello-server

Start the server:

smello-server run

Add two lines to your code:

import smello
smello.init()

import requests
resp = requests.get("https://api.stripe.com/v1/charges")

# Browse captured requests at http://localhost:5110

Smello monkey-patches requests, httpx, and grpc to capture all outgoing traffic. Browse results at http://localhost:5110.

Google Cloud libraries

Many Google Cloud Python libraries — BigQuery, Firestore, Pub/Sub, Analytics Data API (GA4), Vertex AI, Speech-to-Text, Vision, Translation, and others — use gRPC under the hood. Smello captures these calls automatically:

import smello
smello.init()

from google.cloud import bigquery
client = bigquery.Client()
rows = client.query("SELECT 1").result()

# gRPC calls to bigquery.googleapis.com appear at http://localhost:5110

Any library that calls grpc.secure_channel() or grpc.insecure_channel() is automatically captured.

What Smello Captures

• Method, URL, headers, and body
• Response status code, headers, and body
• Duration in milliseconds
• Library used (requests, httpx, or grpc)

Smello redacts sensitive headers (Authorization, X-Api-Key) by default.

Configuration

smello.init(
    server_url="http://localhost:5110",  # where to send captured data
    capture_hosts=["api.stripe.com"],    # only capture these hosts
    capture_all=True,                     # capture everything (default)
    ignore_hosts=["localhost"],          # skip these hosts
    redact_headers=["Authorization"],    # replace values with [REDACTED]
    enabled=True,                         # kill switch
)

All parameters fall back to SMELLO_* environment variables when not passed explicitly:

Parameter	Env variable	Default
enabled	SMELLO_ENABLED	True
server_url	SMELLO_URL	http://localhost:5110
capture_all	SMELLO_CAPTURE_ALL	True
capture_hosts	SMELLO_CAPTURE_HOSTS	[]
ignore_hosts	SMELLO_IGNORE_HOSTS	[]
redact_headers	SMELLO_REDACT_HEADERS	["Authorization", "X-Api-Key"]

Boolean env vars accept true/1/yes and false/0/no (case-insensitive). List env vars are comma-separated.

Supported Libraries

• requests — patches Session.send()
• httpx — patches Client.send() and AsyncClient.send()
• grpc — patches insecure_channel() and secure_channel() to intercept unary-unary calls

Requires

• Python >= 3.10
• smello-server running locally

Links

• Documentation & Source
• smello-server on PyPI