tanstack-fetch 1.6.1: typed params beside your DTO

October 1, 2026

1.6.0 experimented with a route map on createFetch<Routes>(). That is gone.

1.6.1 types URL params from :id / {id}, lets you pass a params map beside your response DTO, and optionally types body on write methods.

The API

import type { NoParams } from 'tanstack-fetch'

type User = { id: string; name: string }
type Params = { id: number }

// params from the URL — no response generic
await api.get('/users/:id', { params: { id } })
await api.get('/users/:id') // ❌ missing id

// response only — options required (TS loses the path literal)
await api.get<User>('/users/:id') // ❌ missing options
await api.get<User[]>('/users', {})

// response + params map — path must include those keys as :id / {id}
await api.get<User, Params>('/users/:id', { params: { id } })
await api.get<User, Params>('/users/:id', { params: {} }) // ❌ missing id
await api.get<User, Params>('/users', { params: { id } }) // ❌ path has no :id
await api.get<User, { userId: number }>('/users/:id', { params: { userId: 1 } }) // ❌ no :userId

// post / put / patch — optional body type (third generic; use NoParams to skip params)
await api.post<User, NoParams, { name: string }>('/users', { body: { name: 'Ada' } })
await api.put<User, Params, { name: string }>('/users/:id', {
  params: { id },
  body: { name: 'Ada' },
})

Same pattern for delete / upload; body typing on post / put / patch / request.

Why two (or three) type args?

TypeScript cannot partially infer generics. Writing only api.get<User>(path) turns the path into string, so :id checks disappear. Pass your params map as the second type argument (and body as the third on write methods) to keep both.

From 1.6.0

Before (1.6.0)	After (1.6.1)
createFetch<Routes>() route map	dropped — use path + params map
untyped / loose params	api.get<User, { id: number }>('/users/:id', …)

Upgrade

npm install tanstack-fetch@1.6.1

See also: Getting started, createFetch.