> For the complete documentation index, see [llms.txt](/llms.txt).
[◆ miniwebtool /api](/)
[Tools](/tools/) [Docs](/docs/) [Reference](/v1/docs) [Pricing](/#pricing) [Log in](/dashboard/login/) [Start free](/billing/checkout/?plan=free)

# Docs

MiniWebtool API gives apps, content sites, workflows, and agents ready-made JSON tools with stable schemas and predictable credit costs. Start with Concepts if you're new. Jump to the [endpoint reference](/v1/docs) when you know what you're calling.
Concepts

### How the API works

Auth, errors, rate limits, credits, versioning, MCP, and when to use hosted utility endpoints.
[
Reference

### Every endpoint, searchable

Scalar UI backed by the live OpenAPI 3.1 spec. Grouped by category, hotkey`K`to search.
](/v1/docs)
[Tool catalog (440)](/tools/) [openapi.json](/v1/openapi.json) [Contact](mailto:support@miniwebtool.com)

## When to use MiniWebtool API

Use MiniWebtool API when your product needs calculators, hashes, counters, date math, finance formulas, converters, or repeatable utility results. You get stable JSON, fixed credit cost, lower latency, and no custom helper code to maintain for each tool.

## Quickstart

Get a key from the [dashboard](/dashboard/), then:

```text
$ curl https://api.miniwebtool.com/v1/tools/percentage-calculator/run \
    -H "Authorization: Bearer $MWT_KEY" \
    -H "Content-Type: application/json" \
    -d '{"mode":"percent_of","a":15,"b":200}'

{"request_id":"01KPW…","tool":"percentage-calculator","credits_used":1,"result":{"mode":"percent_of","a":15,"b":200,"result":30}}
```

Every tool lives under`/v1/tools/<slug>/run`. Slugs are lowercase-hyphenated and never change within a major version.

## Authentication

Pass your key as a bearer token.`X-API-Key`works too if your HTTP client can't set`Authorization`.

```text
Authorization: Bearer mwt_live_<20-hex>_<40-hex>
# or
X-API-Key: mwt_live_...
```

- Keys are scoped to a Project under an Organization. Revoke from the dashboard at any time — invalidation is instant.
- We store only`sha512(key)`and a lookup prefix. A lost key cannot be recovered — rotate instead.
- `env=test`keys skip billing but still count against rate limits — use for staging.

## Errors (RFC 7807)

Every non-2xx response is`application/problem+json`:

```text
{
  "type":   "https://api.miniwebtool.com/errors/insufficient_credits",
  "title":  "Insufficient credits",
  "status": 402,
  "detail": "Plan 'starter' has 0 credits remaining this period.",
  "instance":   "/v1/tools/word-counter/run",
  "request_id": "01KPW…",
  "code":   "insufficient_credits"
}
```

Branch on`code`, not`title`. Titles may change for copy reasons; codes are a stable contract. Known codes:`invalid_request`,`invalid_api_key`,`insufficient_credits`,`rate_limited`,`tool_not_allowed`,`payload_too_large`,`internal_error`.

## Rate limits & headers

Every response — 2xx, 4xx, 5xx — carries these headers:

```text
X-RateLimit-Limit:           10        # plan per-sec cap
X-MWT-Credits-Used:          2         # cost of this call
X-MWT-Credits-Remaining:     49998     # after this call, -1 if unlimited
X-Request-Id:                01KPW…    # opaque ULID, include in support tickets
Retry-After:                 1         # only on 429
X-RateLimit-Reset:           1780…     # only on 429, unix seconds
```

Rate limiting is a sliding 1-second window per organization. Monthly credits reset on the 1st UTC.

## Credits

- Every tool has a fixed`credit_weight`. Text/hash/math tools usually cost 1 credit, simple finance costs 2, and table-heavy finance costs more.
- Weights are declared in the [OpenAPI spec](/v1/openapi.json) under`x-mwt-credit-weight`.
- Validation failures (4xx) and tool 5xx don't charge. Credits are reserved on entry and refunded on failure automatically.
- Free and Starter are hard-capped. Pro, Business, and Scale are hard-capped by default; optional overage is metered per 1K credits only after the customer enables it.

## Versioning

Every response carries`tool_version`. A version bump means either a bug fix (backward-compatible) or a breaking output-shape change — we never change a version in place. The`/v1/`path prefix guarantees the request envelope is stable. New major versions (`/v2/`) ship alongside v1 for 12+ months before v1 deprecation.

## MCP / agent usage

Every tool in the registry is exposed at`/v1/mcp`as a [Model Context Protocol](https://modelcontextprotocol.io) server (JSON-RPC 2.0 over HTTP, spec version`2025-06-18`). Claude, Cursor, and any MCP-capable agent can discover and call tools with your bearer token in one round trip — no SDK, no client codegen, no separate function definitions.

### Endpoint

```text
POST https://api.miniwebtool.com/v1/mcp
Authorization: Bearer mwt_live_...
Content-Type:  application/json
```

### Supported methods

- `initialize`— public handshake; returns server info + protocol version.
- `tools/list`— public; returns every tool with`name`,`title`,`description`, and a JSON Schema`inputSchema`.
- `tools/call`— authenticated; same quota + credit billing path as REST. Response carries both`content[]`(for the LLM) and`structuredContent`(for code).
- `ping`,`notifications/*`— handled per spec.

### Claude Desktop config

```text
// ~/.config/Claude/claude_desktop_config.json  (Linux)
// %APPDATA%\Claude\claude_desktop_config.json  (Windows)
// ~/Library/Application Support/Claude/claude_desktop_config.json  (macOS)
{
  "mcpServers": {
    "miniwebtool": {
      "url": "https://api.miniwebtool.com/v1/mcp",
      "headers": {
        "Authorization": "Bearer mwt_live_..."
      }
    }
  }
}
```

### Try it by hand

```text
# list tools (no key needed)
$ curl -s https://api.miniwebtool.com/v1/mcp \
    -H 'Content-Type: application/json' \
    -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}' \
  | jq '.result.tools[].name'

# call one (needs key)
$ curl -s https://api.miniwebtool.com/v1/mcp \
    -H 'Content-Type: application/json' \
    -H "Authorization: Bearer $MWT_KEY" \
    -d '{"jsonrpc":"2.0","id":2,"method":"tools/call",
         "params":{"name":"percentage-calculator",
                   "arguments":{"mode":"percent_of","a":15,"b":200}}}' \
  | jq.result.structuredContent
```

Deterministic tools are a particularly good fit for agents: let the agent plan, then call hosted tools for calculations, conversions, formatting, and hashing. Every MCP`tools/call`also shows up in the REST`UsageEvent`log — same dashboard, same billing.

## Privacy

- Pure-math tools (interest, hash, percentage) log only`sha256(body)`, never raw input.
- PII-bearing tools (text analysis, parsing) run in`no_body_logs`mode — we record only the byte count.
- Request-id is always logged for debugging — include it when you file a ticket.
- Signed DPA available for Business and Scale plans. [legal@miniwebtool.com](mailto:legal@miniwebtool.com)

## Support

- Email [support@miniwebtool.com](mailto:support@miniwebtool.com) with the failing`X-Request-Id`.
- Feature requests: [support@miniwebtool.com](mailto:support@miniwebtool.com)
© 2026 miniwebtool. API is a separate product from the consumer site. [Terms](https://miniwebtool.com/about/terms-and-disclaimer/#api-terms) [Privacy](https://miniwebtool.com/about/privacy/#api-privacy) [consumer site →](https://miniwebtool.com)