# A/B Test Significance Calculator API

> For the complete documentation index, see [llms.txt](/llms.txt).

Test whether an A/B conversion-rate difference is significant, with lift, z score, p-value, and intervals.

Use this endpoint to add the tool to your app, site, workflow, or agent without rebuilding formulas, validation, examples, and docs.

- Slug: `a-b-test-significance-calculator`
- Category: `math`
- Version: `2026-04-22`
- Credits per successful call: 1
- Starts on: free
- Max payload: 65536 bytes
- Privacy mode: `hash_only`
- Available on: free, starter, pro, business, scale
- Browser tool: https://miniwebtool.com/a-b-test-significance-calculator/

## Endpoint

`POST https://api.miniwebtool.com/v1/tools/a-b-test-significance-calculator/run`

## Request body

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `control_visitors` | `int` | no | control group size |
| `control_conversions` | `int` | no | control conversions |
| `variant_visitors` | `int` | no | variant group size |
| `variant_conversions` | `int` | no | variant conversions |
| `confidence_level` | `str` | no | 95 | 90 | 99 Choices: 95, 90, 99 |
| `test_type` | `str` | no | two_tailed | one_tailed Choices: two_tailed, one_tailed |

## Example request

```json
{
  "control_visitors": 5000,
  "control_conversions": 250,
  "variant_visitors": 5000,
  "variant_conversions": 300,
  "confidence_level": "95",
  "test_type": "two_tailed"
}
```

## cURL

```bash
curl -X POST https://api.miniwebtool.com/v1/tools/a-b-test-significance-calculator/run \
  -H 'Authorization: Bearer mwt_live_YOUR_KEY' \
  -H 'Content-Type: application/json' \
  -d '{"control_visitors":5000,"control_conversions":250,"variant_visitors":5000,"variant_conversions":300,"confidence_level":"95","test_type":"two_tailed"}'
```

## Response envelope

```json
{
  "request_id": "01K...",
  "tool": "a-b-test-significance-calculator",
  "tool_version": "2026-04-22",
  "credits_used": 1,
  "result": {}
}
```

## Errors

Errors are RFC 7807 `application/problem+json`. Branch on `code`, not `title`.

## MCP

Agents can discover and call this tool through `https://api.miniwebtool.com/mcp` or `https://api.miniwebtool.com/v1/mcp` using MCP `tools/list` and `tools/call`.

## Frequently asked

### What does the A/B Test Significance Calculator API do?

Test whether an A/B conversion-rate difference is significant, with lift, z score, p-value, and intervals. Use it to add this utility without rebuilding formulas, validation, examples, and documentation.

### How much does one call cost?

1 credit per successful call. Failed calls do not bill.

### What parameters are required?

Required fields: (none). Full schema at `https://api.miniwebtool.com/v1/openapi.json`.

### Is this deterministic?

Yes. Same input, same output. Tool version: 2026-04-22.