ZWO Format

The @kaiord/zwo package provides reading, writing, and validation of Zwift workout XML files.

Installation

pnpm add @kaiord/core @kaiord/zwo

Usage

Pre-built adapters

import { fromText, toText } from "@kaiord/core";
import { zwiftReader, zwiftWriter } from "@kaiord/zwo";
import { readFile, writeFile } from "node:fs/promises";

// ZWO to KRD
const zwoContent = await readFile("workout.zwo", "utf-8");
const krd = await fromText(zwoContent, zwiftReader);

// KRD to ZWO
const zwoString = await toText(krd, zwiftWriter);
await writeFile("output.zwo", zwoString);

Factory with custom logger

import { createConsoleLogger } from "@kaiord/core";
import { createZwiftReader, createZwiftWriter } from "@kaiord/zwo";

const logger = createConsoleLogger();
const reader = createZwiftReader(logger);
const writer = createZwiftWriter(logger);

API

Function	Description
zwiftReader	Pre-built ZWO text reader
zwiftWriter	Pre-built ZWO text writer
createZwiftReader(logger?)	Factory for ZWO reader with optional logger
createZwiftWriter(logger?)	Factory for ZWO writer with optional logger
createZwiftValidator(logger)	XSD validator (Node.js) or well-formedness checker (browser)

Supported features

• SteadyState intervals
• Warmup and Cooldown ramps
• IntervalsT (structured intervals)
• FreeRide segments
• Power targets (FTP percentage)
• Heart rate and cadence targets
• Text events

ZWO-specific notes

When converting ZWO to KRD:

• Power targets are expressed as FTP percentage (Zwift's native unit)
• Heart rate targets have limited support in ZWO format
• Distance-based durations may be converted to time-based
• Original ZWO-specific data is preserved in extensions.zwift

Ready to convert? Follow the Quick Start.