Quickstart

Pick your framework. Each one needs a single integration point. Django projects can add the Django helpers to cover errors raised outside the view layer.

Wire it up

from fastapi import FastAPI
import errium

app = FastAPI()

# Catches uncaught exceptions, HTTPException (incl. 404/405), and
# request validation errors.
errium.install(app)

from flask import Flask
from errium_flask import ErriumFlask

app = Flask(__name__)

# Covers HTTP exceptions, uncaught exceptions, and pydantic validation errors.
ErriumFlask(app)

from ninja import NinjaAPI
from errium_ninja import register_errium

api = NinjaAPI()

# Overrides Ninja's own handlers for ValidationError, HttpError,
# Http404, and Exception.
register_errium(api)

REST_FRAMEWORK = {
    "EXCEPTION_HANDLER": "errium_drf.errium_exception_handler",
}

See the difference

Post a request that fails validation — say a body missing its password field.

Without Errium, FastAPI hands back Pydantic’s raw output:

{
  "detail": [
    {
      "type": "missing",
      "loc": ["body", "password"],
      "msg": "Field required",
      "input": null
    }
  ]
}

With Errium, the same failure arrives in the standard contract:

{
  "success": false,
  "status_code": 422,
  "code": "VALIDATION_ERROR",
  "message": "Validation failed.",
  "trace_id": "87b003a8-7c15-4a6c-9c76-a05b22b109e2",
  "timestamp": "2026-05-27T12:00:00Z",
  "details": {
    "password": "Password is required."
  }
}

Every error your API returns now uses that shape, whether it came from a validation failure, a 404, or an uncaught KeyError. Each one is also logged on the errium logger with its trace_id, and the same ID comes back in an X-Trace-Id header — see Trace IDs.

Read the field-by-field contract on The response contract.