CalKit

io.github.OlsOls4Published by GitHub account OlsOls4v1.1.0Updated Oct 24, 2026

Public holidays for 150+ countries, business-day maths and timezone lookup

VerifiedStreamable HTTPWeb executableLocation & Lifestyle Productivity & Workflow

Server details

Identifier: io.github.OlsOls4/calkit
Transport: Streamable HTTP
Runtime: Web executable
Trust: Verified
Published: Oct 15, 2026

Security note

MCP servers receive tool arguments from a conversation and may perform external actions. Review what a server can do before you enable it, and give it only the access it needs.

The registry verified the GitHub account OlsOls4 for this listing. That does not show the account is the product's maker.

SourceWeft's checks cover whether the listing is complete and the endpoint answered; they do not review the server's code or what its tools do.

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Overview

AI-generated overview

Remote MCP server for CalKit that gives an assistant public holidays for 150+ countries, business-day calculations and timezone lookup.

What you can do: Look up public holidays for 150+ countries
Add or count business days between dates, with country and subdivision options
Look up timezone information
Each API endpoint is exposed as a tool over Streamable HTTP
When to use it: Useful when scheduling, deadline or delivery-date work depends on national holidays, working days or timezones, for example planning across countries or computing a date N business days out.
Requirements: A remote Streamable HTTP endpoint; no local runtime. Requires a RapidAPI subscription to CalKit (free plan available) and the headers X-RapidAPI-Key (secret) and X-RapidAPI-Host on every request. The client must support custom headers.

Before you install

The X-RapidAPI-Key secret is sent with every request and is tied to your RapidAPI account and plan quotas; keep it out of shared configs. Requests and their parameters go through RapidAPI as a third-party gateway.

Installation

In SourceWeft

Open CalKit in the dashboard and add it to a workspace.
Connect Custom headers credentials. They are stored privately and never shown on public pages.
Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/io.github.OlsOls4%2Fcalkit/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "calkit": {
      "type": "http",
      "url": "https://calkit-public-holidays-business-days-timezones.p.rapidapi.com/mcp",
      "headers": {
        "X-RapidAPI-Key": "<VALUE>",
        "X-RapidAPI-Host": "<VALUE>"
      }
    }
  }
}

README

Developer utility APIs + remote MCP servers

Thirteen small, focused REST APIs for everyday developer jobs: validating emails, phones and IBANs, IP geolocation, PDFs, images, QR codes, fraud scoring, token counting and more. Each one is its own product on RapidAPI with a free plan, full OpenAPI docs, and a built-in remote MCP server so AI agents (Claude, Cursor, VS Code, n8n, LangChain) can call it as tools.

Free tier on every API: subscribe on RapidAPI, copy your key, call it.
MCP built in: every API exposes Streamable HTTP MCP at https://<host>.p.rapidapi.com/mcp, and each is listed in the official MCP Registry as io.github.OlsOls4/<kit>.
No heavy dependencies on your side: plain HTTPS + JSON from any language or no-code tool.

The APIs

API	What it does	RapidAPI	MCP endpoint	Tutorial
WebKit	Email validation, link previews and article-to-Markdown extraction for AI agents	Listing	`https://webkit-email-validator-link-preview-article-extractor.p.rapidapi.com/mcp`	dev.to
DomainKit	DNS records, SSL certificate, WHOIS/RDAP and website tech scan for any domain	Listing	`https://domainkit-dns-ssl-whois-website-tech-lookup.p.rapidapi.com/mcp`	dev.to
QRKit	Generate QR codes (URL, WiFi, vCard) and barcodes as PNG/SVG	Listing	`https://qrkit-qr-code-barcode-generator.p.rapidapi.com/mcp`	dev.to
TextKit	Sentiment, language detection, readability, keywords, summaries and profanity filtering	Listing	`https://textkit-sentiment-language-readability-keywords.p.rapidapi.com/mcp`	dev.to
PhoneKit	Phone number validation, formatting, carrier, line type and timezone	Listing	`https://phonekit-phone-number-validation-carrier-line-type.p.rapidapi.com/mcp`	dev.to
ValidKit	Validate IBAN, EU VAT, card numbers, ISBN, BIC, EAN and postcodes	Listing	`https://validkit-iban-vat-card-isbn-bic-postcode-validator.p.rapidapi.com/mcp`	dev.to
GeoIP	IP geolocation: country, continent, ASN and ISP lookup	Listing	`https://geoip-ip-geolocation-asn-isp-lookup.p.rapidapi.com/mcp`	dev.to
DocKit	Extract text and metadata from PDFs; convert Markdown or text to PDF	Listing	`https://dockit-pdf-text-extraction-markdown-to-pdf.p.rapidapi.com/mcp`	dev.to
FraudKit	Fraud risk score for signups and orders from email, IP, phone and user-agent	Listing	`https://fraudkit-fraud-risk-score-for-signups-orders.p.rapidapi.com/mcp`	dev.to
ImageKit	Resize, convert to WebP, compress, crop, rotate and strip EXIF from images	Listing	`https://imagekit-resize-convert-to-webp-compress-crop.p.rapidapi.com/mcp`	dev.to
UK PostcodeKit	UK postcode lookup, nearest postcodes, autocomplete and distance (OS open data)	Listing	`https://uk-postcodekit-postcode-lookup-nearest-distance.p.rapidapi.com/mcp`	dev.to
LLMKit	Token counting, RAG chunking, truncation, HTML to Markdown and JSON repair	Listing	`https://llmkit-token-counter-rag-chunker-json-repair.p.rapidapi.com/mcp`	dev.to
CalKit	Public holidays for 150+ countries, business-day maths and timezone lookup	Listing	`https://calkit-public-holidays-business-days-timezones.p.rapidapi.com/mcp`	dev.to

Also available (newer):

CurrencyKit: ECB euro reference exchange rates: latest, historical, time series and currency conversion. RapidAPI · MCP https://currencykit-ecb-exchange-rates-currency-converter.p.rapidapi.com/mcp
VATKit: Live EU VAT number checks via VIES with company name/address, VAT formats and EU VAT rates. RapidAPI · MCP https://vatkit-eu-vat-number-check-vies-vat-rates.p.rapidapi.com/mcp

Quickstart (REST)

bash

curl -G "https://calkit-public-holidays-business-days-timezones.p.rapidapi.com/business-days/add" \  -d date=2026-12-23 -d days=5 -d country=GB -d subdiv=ENG \  -H "X-RapidAPI-Key: YOUR_RAPIDAPI_KEY" \  -H "X-RapidAPI-Host: calkit-public-holidays-business-days-timezones.p.rapidapi.com"

curl -G "https://calkit-public-holidays-business-days-timezones.p.rapidapi.com/business-days/add" \  -d date=2026-12-23 -d days=5 -d country=GB -d subdiv=ENG \  -H "X-RapidAPI-Key: YOUR_RAPIDAPI_KEY" \  -H "X-RapidAPI-Host: calkit-public-holidays-business-days-timezones.p.rapidapi.com"

Swap the host for any API in the table. Every request goes through RapidAPI with X-RapidAPI-Key and X-RapidAPI-Host.

Quickstart (MCP)

Add any API as a remote MCP server in a client that supports Streamable HTTP with custom headers, for example:

json

{  "mcpServers": {    "calkit": {      "type": "http",      "url": "https://calkit-public-holidays-business-days-timezones.p.rapidapi.com/mcp",      "headers": {        "X-RapidAPI-Key": "YOUR_RAPIDAPI_KEY",        "X-RapidAPI-Host": "calkit-public-holidays-business-days-timezones.p.rapidapi.com"      }    }  }}

{  "mcpServers": {    "calkit": {      "type": "http",      "url": "https://calkit-public-holidays-business-days-timezones.p.rapidapi.com/mcp",      "headers": {        "X-RapidAPI-Key": "YOUR_RAPIDAPI_KEY",        "X-RapidAPI-Host": "calkit-public-holidays-business-days-timezones.p.rapidapi.com"      }    }  }}

The server answers tools/list with that API's endpoints as tools.

What's in this repo

main.py and one folder per API (webkit, domainkit, qrkit, ...): the FastAPI service behind all listings.
mcpserver.py: the MCP layer that turns each API's routes into tools.
openapi/: OpenAPI specs for each API.
mcp-registry/: server.json files published to the official MCP Registry.

Data and licences

GeoIP and FraudKit use DB-IP Lite (CC BY 4.0). UK PostcodeKit uses OS Code-Point Open (Open Government Licence v3.0; contains OS data © Crown copyright and database right). PhoneKit uses Google libphonenumber (Apache 2.0). Full attributions are in each API's docs on RapidAPI.

Support

Questions, bugs or feature requests: open an issue or use the Discussions tab on the RapidAPI listing.

Source: README.md at commit d186ed8

Tools

This server asks for a credential such as an API key, so SourceWeft could not read its tools without one and has not indexed them.

Version history

v1.1.0LatestOct 15, 2026

Score

75% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

Reached in the last 30 daysRequired25 pts
Auth declaredRequired10 pts
Tools listed15 pts
Answer tools/list without a credential, or ship a package that starts in a sandbox without one.
DescriptionRequired15 pts
Logo10 pts
Documentation15 pts
License10 pts
Declare a license in the repository or the registry entry.