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

# SEC Filing Diff API — Compare Amendments and Document Versions

> Compare SEC filing amendments side by side via API. Detect changes between 10-K/A, 10-Q/A, and other amended filings with structured diffs. Get started free at secapi.ai/signup.

When companies amend their SEC filings, the changes can be buried in hundreds of pages of identical text. SEC API's diff engine compares any two versions of a filing and returns a structured changeset — additions, deletions, and modifications — so you can see exactly what changed without reading the entire document.

## Capabilities

<CardGroup cols={2}>
  <Card title="Structured diffs" icon="code-compare">
    Additions, deletions, and modifications returned as structured JSON with section-level context.
  </Card>

  <Card title="Amendment comparison" icon="file-circle-check">
    Compare an original 10-K with its 10-K/A amendment automatically. Works with any form type that has amendments.
  </Card>

  <Card title="Section-level granularity" icon="scissors">
    Changes grouped by section (e.g., Item 1A Risk Factors, Item 8 Financial Statements) for quick navigation.
  </Card>

  <Card title="Numeric change detection" icon="hashtag">
    Financial figures that changed are flagged with old and new values for instant identification of restated numbers.
  </Card>
</CardGroup>

## Quick start

Compare an original 10-K with its amendment:

```bash theme={null}
curl -H "x-api-key: $SECAPI_API_KEY" \
  "https://api.secapi.ai/v1/filings/diff?accession_a=0000320193-24-000081&accession_b=0000320193-25-000003"
```

```json theme={null}
{
  "original": "0000320193-24-000081",
  "amendment": "0000320193-25-000003",
  "form": "10-K/A",
  "changes": [
    {
      "section": "Item 8 - Financial Statements",
      "type": "modification",
      "description": "Restated revenue figure for Q3 2024",
      "old_text": "Revenue: $94,930,000,000",
      "new_text": "Revenue: $94,880,000,000"
    },
    {
      "section": "Item 1A - Risk Factors",
      "type": "addition",
      "description": "New risk factor added",
      "new_text": "Regulatory changes in the European Union may impact..."
    }
  ],
  "total_changes": 12,
  "sections_affected": 3
}
```

## Use cases

### Restatement detection

Automatically detect when companies restate financial figures by diffing 10-K and 10-K/A filings. Flag the specific numbers that changed.

### Compliance monitoring

Regulatory teams can track what changed in amended filings from issuers they monitor without manually reviewing hundreds of pages.

### Audit trail creation

Build an auditable record of all changes between filing versions for legal, compliance, or research purposes.

### Risk factor monitoring

Track changes to Item 1A (Risk Factors) between annual filings to detect emerging risks and removed risks over time.

## API endpoints

| Endpoint                     | Description                          |
| ---------------------------- | ------------------------------------ |
| `GET /v1/filings/diff`       | Compare two filing accession numbers |
| `GET /v1/filings/amendments` | Find all amendments for a filing     |

## Why SEC API for filing diffs

| Feature                  | SEC API       | Raw EDGAR     | sec-api.io | Manual review |
| ------------------------ | ------------- | ------------- | ---------- | ------------- |
| Structured diff output   | Yes           | No            | No         | N/A           |
| Section-level grouping   | Yes           | No            | No         | Manual        |
| Numeric change detection | Yes           | No            | No         | Manual        |
| REST API                 | Yes           | No            | No         | N/A           |
| Any form type            | Yes           | Manual        | No         | Manual        |
| Pricing                  | Pay-as-you-go | Free (manual) | N/A        | Labor cost    |

## Get started

<Card title="Get your API key" icon="key" href="/getting-started">
  Start comparing SEC filings in under 60 seconds. 150 free API calls (one-time).
</Card>

* [10-K Section Extraction API](/seo/sec-10k-section-extraction-api)
* [Full-Text Search API](/seo/sec-full-text-search-api)
* [API Reference](/api-reference)