> 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/) [get free key →](/billing/checkout/?plan=free)
docs read in ~5 minutes

# Docs

Everything below applies to all 1080 endpoints — learn the envelope once and every tool works the same way. New here? Read top to bottom. Know what you're calling? Jump to the [endpoint reference](/v1/docs).
when-to-use quickstart auth errors rate-limits credits versioning mcp privacy support
concepts

### How the API works

Auth, errors, rate limits, credits, versioning, and MCP — one envelope shared by every endpoint.
[
reference

### Every endpoint, searchable

Interactive UI on the live OpenAPI 3.1 spec, grouped by category. Hotkey K to search.
](/v1/docs)
[Tool catalog (1080)](/tools/) [openapi.json](/v1/openapi.json) [Contact](mailto:support@miniwebtool.com)

## 01 When to use MiniWebtool API

Use it when your product needs calculators, hashes, counters, date math, finance formulas, converters, or other repeatable utility results. You get stable JSON, a fixed credit cost per call, and no helper code to write, test, and maintain for each tool. If the utility is core IP for your business, build it yourself; if it's plumbing, call ours.

## 02 Quickstart

[Get a free key](/billing/checkout/?plan=free) (1,000 credits/mo, no card), 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.

## 03 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.

## 04 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`.

## 05 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.

## 06 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`— your build can budget before you ever ship.
- 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 you enable it. No silent overage bills.

## 07 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.

## 08 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 three tools:`search_tools`and`get_tool`(free, no key) and`run_tool`(billed). Append`?tools=all`to the server URL to list every tool directly, or`?category=finance`to add one category.
- `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.

## 09 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)

## 10 Support

- Email [support@miniwebtool.com](mailto:support@miniwebtool.com) with the failing`X-Request-Id`— it links directly to our logs.
- Missing a tool you need? [Request it](mailto:support@miniwebtool.com) — the catalog grows from customer asks first.
API OPERATIONAL v1 · OpenAPI 3.1 · MCP 2025-06-18
[terms](https://miniwebtool.com/about/terms-and-disclaimer/#api-terms) [privacy](https://miniwebtool.com/about/privacy/#api-privacy) [llms.txt](/llms.txt) [consumer site →](https://miniwebtool.com) © 2026 miniwebtool
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Every tool on miniwebtool.com, as a JSON API.
1080 ready-made endpoints — calculators, converters, text, hashes, finance — behind one key, one stable JSON envelope, and a fixed credit cost. Built for apps, sites, and AI agents.
- 1 Try it right here — every tool page has a playground with a prefilled test key. No signup.
- 2 Get your own key by email — 1,000 free calls every month, no card required.
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