> ## Documentation Index
> Fetch the complete documentation index at: https://docs.isofold.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Data Handling

> Understand how Isofold processes, routes, and protects your data.

## How Isofold Handles Data

Isofold is designed to operate **without retaining** any sensitive data. It processes SQL queries in transit and guarantees that:

* Query results are never stored
* Sensitive input is not logged
* All computation happens in-memory or in a configured warehouse

***

## Query Lifecycle

Each query follows this lifecycle:

1. **Ingress**
   The query arrives at the Isofold proxy via HTTP, JDBC, or native wire protocol.

2. **Rewrite Phase**
   The SQL is parsed, transformed, and optionally verified.

3. **Execution Phase**
   The rewritten query is sent to your data warehouse. Results are streamed back directly to the client.

4. **Egress**
   The original query and its result are discarded unless verification mode is enabled.

***

## Logging & Redaction

By default, Isofold logs only the following:

* Query fingerprint (e.g. hashed SELECT pattern)
* Warehouse used
* Execution metadata (latency, cost, rewrite path)
* High-entropy trace ID

No SQL contents or results are persisted.

You may enable full SQL logging in test environments using:

```bash theme={null}
export ISOFOLD_LOG_QUERIES=true
```

<Warning icon="exclamation-triangle">
  We strongly advise against enabling full SQL logging in production environments.
</Warning>

***

## Data Residency

* Hosted mode: All query processing occurs in **transit**, at the Fly.io edge region nearest to the client.
* Self-hosted mode: Data never leaves your environment. Isofold can run inside the same region or VPC as your warehouse.

***

## Supported Isolation Levels

| Deployment Mode   | Data Retention | TLS Required | VPC Integration | Logging Scope       |
| ----------------- | -------------- | ------------ | --------------- | ------------------- |
| Hosted (Default)  | None           | Yes          | ✕               | Fingerprints only   |
| Self-hosted (VPC) | None           | Optional     | ✓               | Configurable        |
| Debug Mode        | Optional       | Yes          | ✓ / ✕           | Full query + result |

***

Next: View the [Security Network Diagram](/security/network-diagram)