Fetch Client

pub package package publisher

This package provides package:http client based on Fetch API.

It's a drop-in solution for extensions with Manifest V3.


  • Cancel requests.
  • Support data streaming:
    • Get response as Stream.
    • Optionally send Stream as request body (supported only in Chromium 105+ based browsers).
  • Get access to redirect URL and status.
  • Support non-200 responses (fetch will only fail on network errors).
  • Simulate redirects responses via probe request and artificial location header.


Large payload

This modules maps keepalive to BaseRequest.persistentConnection which is true by default.

Fetch spec says that maximum request size with keepalive flag is 64KiB:

4.5. HTTP-network-or-cache fetch

8.10.5: If the sum of contentLength and inflightKeepaliveBytes is greater than 64 kibibytes, then return a network error.

Source: Fetch. Living Standard — Last Updated 19 June 2023

Therefore if your request is larger than 64KiB (this includes some other data, so effectively recommended check is 60KiB) you must explicitly set BaseRequest.persistentConnection to false, otherwise request will fail.

Request streaming

Request streaming is supported only in Chromium 105+ based browsers and requires server to use HTTP/2 or HTTP/3.

See MDN compatibility chart and Chrome Developers blog for more info.


Fetch based HTTP client. Exports necessary fetch request options and client with response.