Laytime Calculator Pro

AI-powered laytime, demurrage and despatch calculation for dry-bulk and tanker chartering. Send a Charter Party, Fixture Recap, Notice of Readiness (NOR) or Statement of Facts (SoF) — get back a full, auditable laytime statement with the demurrage / despatch settlement.

Built for software teams in shipping: integrate it into your own systems over a plain REST API, or plug it into an AI assistant via the Model Context Protocol (MCP). Same key, same quota, same engine.

• 🌐 Product: https://navitt.com/web
• 🔑 API access & pricing: https://navitt-mcp.marine-356.workers.dev/authorize
• 📇 MCP Registry: io.github.shipping-ship-it/laytime-calculator-pro
• ✉️ Contact: [email protected]

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What it does

Laytime calculation requires holding every charter-party term in mind at once — laycan, NOR validity, turn time, SHINC/SHEX, weather working days, exceptions, half-rate periods, reversible vs non-reversible time. Miss one clause and the settlement is wrong. This service reads the documents, applies the terms and returns a day-by-day calculation you can audit, with the final demurrage or despatch figure.

• Accepts Charter Party, Fixture Recap, NOR, Statement of Facts, Bills of Lading
• Input as plain text and/or files (PDF, image, Excel)
• Returns a full, line-by-line laytime statement plus the settlement
• Works with any language or platform over REST — no AI required on your side

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Quick start (REST)

curl -X POST https://navitt-mcp.marine-356.workers.dev/api/calculate \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "text": "NOR tendered 01 Jun 08:00. Loading 01 Jun 12:00 to 03 Jun 18:00. Laytime allowed 3 days SHINC. Demurrage USD 10000/day. Despatch half demurrage."
  }'

Response:

{
  "result": "… full day-by-day laytime statement and demurrage/despatch settlement …",
  "remaining": 92
}

remaining is the number of calculations left on your plan.

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Authentication

Every request must include your API key in the x-api-key header. Keys are issued after sign-up on the access & pricing page.

x-api-key: YOUR_API_KEY

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REST API reference

POST /api/calculate

Base URL: https://navitt-mcp.marine-356.workers.dev

Headers

Header	Required	Value
x-api-key	yes	Your API key
Content-Type	yes	application/json

Body (JSON) — provide text, documents, or both:

Field	Type	Required	Description
text	string	no*	Plain-text input, e.g. a pasted fixture recap or SoF
documents	array	no*	Document files, base64-encoded (see below)
instructions	string	no	Extra instructions, e.g. "SHEX applies. Demurrage USD 3,500/day"

* At least one of text or documents must be supplied.

documents[] item

Field	Type	Description
mimeType	string	e.g. application/pdf, image/png
data	string	base64-encoded file content

Response 200 OK

Field	Type	Description
result	string	The full laytime statement and settlement
remaining	integer	Calculations left on your plan

Errors

Status	Meaning
401	Missing or invalid x-api-key
400	Body is not valid JSON, or neither text nor documents
402	Calculation quota exhausted (NO_CREDITS) — top up
502	Calculation engine error — retry later

Each successful request consumes one calculation from your plan.

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Example: sending a document (Node.js)

import { readFileSync } from "node:fs";

const data = readFileSync("charter_party.pdf").toString("base64");

const res = await fetch("https://navitt-mcp.marine-356.workers.dev/api/calculate", {
  method: "POST",
  headers: {
    "x-api-key": process.env.LAYTIME_API_KEY,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    documents: [{ mimeType: "application/pdf", data }],
    instructions: "SHINC. Demurrage USD 12,000/day, despatch half demurrage.",
  }),
});

const { result, remaining } = await res.json();
console.log(result);
console.log("Calculations left:", remaining);

Example: Python

import base64, requests

with open("statement_of_facts.pdf", "rb") as f:
    data = base64.b64encode(f.read()).decode()

r = requests.post(
    "https://navitt-mcp.marine-356.workers.dev/api/calculate",
    headers={"x-api-key": "YOUR_API_KEY"},
    json={"documents": [{"mimeType": "application/pdf", "data": data}]},
)
print(r.json()["result"])

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MCP server

The same calculator is available as a Model Context Protocol server, so an AI assistant can call it directly as a tool.

• Endpoint: https://navitt-mcp.marine-356.workers.dev/mcp (streamable HTTP, OAuth-protected)
• Registry name: io.github.shipping-ship-it/laytime-calculator-pro
• Tool: calculate_laytime

Tool input

Field	Type	Description
text	string	Plain-text input (recap, SoF, etc.)
documents	array	{ mimeType, data } — base64-encoded files
instructions	string	Optional extra instructions

Authorize and obtain access on the access & pricing page.

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Pricing

Pay-as-you-go: USD 1,000 for 500 calculations (USD 2 per calculation), by card or by invoice to a corporate account. Corporate rates available for teams. See the access & pricing page or contact [email protected].

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About

Built by AGRIX / Navitt — modern tools for shipping. BIMCO member 181628.

• https://agrix.world
• https://navitt.com