# Route Python and native clients through a World

A Node preload does not intercept Python, curl, Go or a native binary. Those clients must honor the World's proxy and session CA, or a vendor-supported endpoint override. Being launched in a World does not by itself prove every network call was routed.

## A Python request to the real vendor hostname

Use Node 22.6 or newer, npm and Python 3 in an empty directory. The example first creates a customer using the real Node SDK, then reads it from Python through the scoped HTTPS proxy.

```json file=package.json
{
  "name": "acme-web",
  "private": true,
  "type": "module",
  "dependencies": {
    "stripe": "17.7.0"
  },
  "devDependencies": {
    "@volter/world": "3.0.63",
    "@volter/twin-stripe": "3.0.1"
  }
}
```

```text file=.env.example
STRIPE_SECRET_KEY=
```

```js file=check.mjs
import assert from 'node:assert/strict';
import Stripe from 'stripe';
const stripe = new Stripe(process.env.STRIPE_SECRET_KEY, { maxNetworkRetries: 0 });
const made = await stripe.customers.create({ email: 'ada@example.com', name: 'Ada' });
assert.equal((await stripe.customers.retrieve(made.id)).email, 'ada@example.com');
assert.equal(made.created, Date.parse('2026-01-15T12:00:00Z') / 1000);
console.log('create, read and frozen timestamp passed');
```

```python file=read-customer.py
import json, os, ssl, urllib.request
proxy = os.environ.get('HTTPS_PROXY') or os.environ.get('https_proxy')
ca = os.environ.get('CURL_CA_BUNDLE') or os.environ.get('SSL_CERT_FILE')
if not proxy or not ca: raise RuntimeError('Expected the World proxy and its session CA')
client = urllib.request.build_opener(urllib.request.ProxyHandler({'https': proxy}), urllib.request.HTTPSHandler(context=ssl.create_default_context(cafile=ca)))
request = urllib.request.Request('https://api.stripe.com/v1/customers', headers={'Authorization': 'Bearer ' + os.environ['STRIPE_SECRET_KEY']})
with client.open(request) as response: customers = json.load(response)
assert any(c.get('email') == 'ada@example.com' for c in customers['data'])
print('Python real-hostname request read the seeded customer')
```

```bash
npm install
npx volter world init --name native-client --twins stripe
npx volter world up
npx volter world clock set 2026-01-15T12:00:00Z
npx volter world run -- node check.mjs
npx volter world run -- python3 read-customer.py
```

```text
Python real-hostname request read the seeded customer
```

The Python code explicitly uses the inherited proxy and its CA. It calls `api.stripe.com`, keeps TLS verification enabled, and receives the same stored customer. It uses only Python's standard library. Do not print the proxy environment, bearer keys or CA custody into a bug report.

```bash
npx volter world log
npx volter world down
```

## Other clients

| Client behavior | Configure | Verify |
|---|---|---|
| Honors `HTTPS_PROXY` and a CA path | Run through the World; select that client's supported trust variable or explicit CA option | A vendor request and expected state/log result |
| Has its own SDK/CLI endpoint override | Use the override declared by the twin, such as `AWS_ENDPOINT_URL` | The selected endpoint, SDK result and log |
| Ignores proxy variables | Set its documented proxy/CA options, or a supported explicit endpoint | Do not infer routing from the parent shell |
| Uses raw sockets, native DNS or an unsupported transport | Use the appropriate enforced Machine/executor boundary when isolation is required | Actual boundary evidence; cooperative sandbox alone is insufficient |

`npx volter world shell` opens a subshell with World routing. `eval "$(npx volter world activate)"` activates a compatible shell; `deactivate` restores it. Prefer `world run` for bounded scripts so the caller's shell is not left activated. Closing a shell does not tear down the World.

A CA trusted through environment variables is scoped to cooperating clients, not installed into the system trust store. Never turn off TLS verification to get a request through. Sandbox mode refuses untwinned destinations in cooperating clients, but cannot constrain a binary that ignores its mediation. See [transport coverage](../contributing/architecture.md#outbound-transport-coverage), [CLI](../reference/cli.md) for remote commands, and [recovery](./recover-a-failed-call.md) for diagnostic commands.

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