remotion-dev/remotion · error · Exception

REMOTION_APP_REGION is not set

Error message

REMOTION_APP_REGION is not set

What it means

Raised by the example test client testclient_render_media.py when the REMOTION_APP_REGION environment variable is empty after dotenv loading. The example scripts refuse to construct a RemotionClient without an AWS region, because the underlying boto3 clients need one to make calls.

Source

Thrown at packages/lambda-python/testclient_render_media.py:14

from remotion_lambda import RenderMediaParams, Privacy, ValidStillImageFormats, Webhook
from remotion_lambda import RemotionClient
import os
from dotenv import load_dotenv
import boto3
from botocore.config import Config

load_dotenv()

# Load env variables
REMOTION_APP_REGION = os.getenv('REMOTION_APP_REGION')
if not REMOTION_APP_REGION:
    raise Exception("REMOTION_APP_REGION is not set")

REMOTION_APP_FUNCTION_NAME = os.getenv('REMOTION_APP_FUNCTION_NAME')
if not REMOTION_APP_FUNCTION_NAME:
    raise Exception("REMOTION_APP_FUNCTION_NAME is not set")

REMOTION_APP_SERVE_URL = os.getenv('REMOTION_APP_SERVE_URL')
if not REMOTION_APP_SERVE_URL:
    raise Exception("REMOTION_APP_SERVE_URL is not set")


# --- NEW: Create a custom botocore Config for timeouts ---
# This configuration will apply to both S3 and Lambda clients created by RemotionClient
# if passed via the botocore_config parameter.
custom_botocore_config = Config(
    connect_timeout=30,  # Max 30 seconds to establish a connection
    read_timeout=60,     # Max 60 seconds to receive data after connection
    retries={'max_attempts': 3, 'mode': 'adaptive'}, # Retry up to 3 times on certain errors
    # You can add more settings here, e.g., proxies

View on GitHub (pinned to 78fe4bb3fd)

Solutions

  1. Create packages/lambda-python/.env from .env.example and set REMOTION_APP_REGION (e.g. 'us-east-1').
  2. Run the script from packages/lambda-python so load_dotenv() picks up the local .env.
  3. Export the variable inline: `REMOTION_APP_REGION=us-east-1 python testclient_render_media.py`.
  4. Verify with `python -c "import os;from dotenv import load_dotenv;load_dotenv();print(os.getenv('REMOTION_APP_REGION'))"`.

Example fix

// before
# .env is missing or empty
// after
# packages/lambda-python/.env
REMOTION_APP_REGION=us-east-1
REMOTION_APP_FUNCTION_NAME=my-render-fn
REMOTION_APP_SERVE_URL=https://example.com/site
Defensive patterns

Strategy: validation

Validate before calling

import os
from dotenv import load_dotenv
load_dotenv()
required = ['REMOTION_APP_REGION', 'REMOTION_APP_FUNCTION_NAME', 'REMOTION_APP_SERVE_URL']
missing = [k for k in required if not os.getenv(k)]
if missing:
    raise SystemExit(f'Missing env vars: {missing}. Copy .env.example to .env and fill them.')

Type guard

def has_region(v): return isinstance(v, str) and v.strip() != ''

Try / catch

try:
    assert os.getenv('REMOTION_APP_REGION'), 'REMOTION_APP_REGION is not set'
except AssertionError as e:
    print(e); sys.exit(1)

Prevention

When it happens

Trigger: Running `python testclient_render_media.py` without a .env file in the working directory, or with REMOTION_APP_REGION missing/blank in that file. Also occurs if load_dotenv() does not find the .env because the script is run from a different cwd.

Common situations: Fresh checkout of the lambda-python package without copying .env.example to .env; running the script from the repo root instead of packages/lambda-python; CI shells that strip the environment.

Related errors

AI-assisted analysis of remotion-dev/remotion@78fe4bb3fd (2026-08-12). Data as JSON: /api/errors/62e4d638f66b3131. Report an issue: GitHub.