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

# Welcome to AuditRails — Tamper-Proof Audit Logging

> AuditRails delivers tamper-proof audit logging with SHA-256 hash chains, WORM storage, and built-in compliance coverage for SOC 2, HIPAA, and PCI DSS.

AuditRails gives your application a permanent, tamper-evident record of everything that matters. Every event you log is cryptographically chained to the one before it using SHA-256, stored in WORM-compliant S3 Object Lock storage, and indexed for sub-second querying — so you always know exactly what happened, when, and who did it, with proof that the record has never been altered.

## Key Features

<CardGroup cols={2}>
  <Card title="Immutable Hash Chains" icon="link" href="/concepts#hash-chains">
    Every event is SHA-256 chained to the previous one. Any tampering instantly breaks the chain and is detected automatically.
  </Card>

  <Card title="WORM Storage" icon="lock" href="/concepts#storage">
    Logs are written to S3 Object Lock in COMPLIANCE mode — once written, they cannot be deleted or modified by anyone, including AuditRails staff.
  </Card>

  <Card title="16+ Compliance Frameworks" icon="shield-check" href="/guides/compliance-mapping">
    Out-of-the-box audit trails for SOC 2, HIPAA, ISO 27001, GDPR, PCI DSS, and 13 more frameworks — ready for your next audit.
  </Card>

  <Card title="Drop-In SDKs" icon="code" href="/sdks/overview">
    Official SDKs for Node.js, PHP, Python, Go, and Java. Add tamper-proof logging to any application in minutes with a single API call.
  </Card>
</CardGroup>

## How It Works

Every event you send passes through a four-stage pipeline that guarantees integrity and durability:

```
Your Application
      │
      ▼
 AuditRails SDK / REST API
  (adds log_id, tenant_id, timestamp)
      │
      ▼
 Hash Chain Engine
  hash = SHA-256(prev_hash + payload + timestamp_ms)
      │
      ├──▶  Hot Storage (ClickHouse) — fast search & dashboards
      │
      └──▶  Cold Storage (S3 Object Lock COMPLIANCE) — WORM, immutable
```

Events are hashed on ingest, appended to your tenant's hash chain, and fanned out to both hot storage for real-time querying and cold storage for long-term, tamper-proof retention. No event is ever overwritten or deleted from the chain.

## Endpoints

| Resource      | URL                         |
| ------------- | --------------------------- |
| REST API base | `https://api.auditrails.io` |
| Dashboard     | `https://app.auditrails.io` |

## Get Started

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/quickstart">
    Create an account, get your API key, and log your first event in under five minutes.
  </Card>

  <Card title="API Reference" icon="terminal" href="/api-reference/overview">
    Full reference for every endpoint, request field, and response shape.
  </Card>

  <Card title="SDK Guides" icon="book" href="/sdks/overview">
    Language-specific guides for Node.js, PHP, Python, Go, and Java.
  </Card>

  <Card title="Compliance Guides" icon="clipboard-check" href="/guides/compliance-mapping">
    How AuditRails satisfies the audit logging requirements of SOC 2, HIPAA, GDPR, PCI DSS, and more.
  </Card>
</CardGroup>