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JSON to TypeScript

Paste a JSON sample and get matching TypeScript interfaces — nested objects, arrays, optional properties and unions included.

How the types are inferred

Each value gets the matching TypeScript type: string, number, boolean or null. Nested objects become their own named interfaces (named after the property, with arrays singularised: items becomes Item). For arrays, all elements are merged into one type: a property that is missing from some elements becomes optional (b?: string), and values of different types become a union (string | number). Empty arrays become unknown[].

A single JSON sample can only show what that sample contains, so check the result against your API documentation: a field that is always null in your sample may hold another type in real data. Everything is worked out in your browser and your JSON is never uploaded.

Mock Data Generator

Generate fake test data in JSON, CSV or SQL: names, UK addresses, emails, phone numbers, dates and IDs. Choose columns and rows.

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MIME Type Lookup

Look up the MIME type (Content-Type) for any file extension, or find the extensions for a MIME type. Searchable list of common types.

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Common Ports Lookup

Look up well-known TCP and UDP port numbers and the services that use them, such as 22 SSH, 443 HTTPS and 3306 MySQL.

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XML to JSON Converter

Convert XML to JSON with clear error messages: choose attribute and text naming, keep arrays, and convert numbers. Runs in your browser.

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Cron Schedule Simulator

Next runs of a cron expression in server, UTC and your time zone, with skipped and repeated times at daylight saving changes.

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Server Region Latency Estimator

Estimate the theoretical round-trip time from your users to AWS, Google Cloud and Azure regions from distance alone, as a range. No pings, no measurements.

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