How to Convert cURL to Fetch for Frontend Projects

Turn cURL commands into Fetch API code with a repeatable workflow for browser apps, React, and Next.js.

July 24, 2024·6 min read

Why Developers Convert cURL to Fetch

API documentation often ships with cURL examples, but frontend code usually needs fetch(). Converting by hand is repetitive and easy to get wrong.

Map Each cURL Part

URL becomes the first fetch argument
Headers move into headers
Method maps to method
Body data becomes body

Example

curl -X POST https://api.example.com/users \
  -H "Content-Type: application/json" \
  -d '{"name":"Ada"}'

await fetch("https://api.example.com/users", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ name: "Ada" })
})

Common Pitfalls

Forgetting JSON.stringify
Copying shell quotes directly into JavaScript
Missing auth headers
Not handling non-2xx responses

Use cURL to Fetch for the conversion step, then inspect headers with HTTP Header Parser if a request still fails.

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