New builtin fetch alpha

[RobertCraigie]

We've been working on an alpha version of the SDK that alongside many other cleanups, migrates from node-fetch to builtin fetch.

You can try it out by installing the 0.34.0-alpha.0 version:

pnpm add @anthropic-ai/sdk@alpha

The core happy path of the SDK remains the same, your existing method calls should just work! However you may run into typing issues as we now expect that fetch is defined as a global.

There are many other small breaking changes which you may run into, we'll share a full migration guide as soon as possible.

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Please share feedback on anything you think could be improved or if you run into any issues! Hope this is a nice early present for you all :)

Important

Unfortunately we cannot guarantee support over the holiday break (December 20th - January 6th inclusive) but we will go through every comment as soon as possible.

[Nishchit14]

ky is a great replacement of fetch (it's a wrapper with great DX., sharing here incase you'd like to consider it.

[RobertCraigie]

Thanks! However we're not considering other HTTP libraries as one great benefit of just depending on the builtin fetch function is that, among other things, we now have zero dependencies!

[Nishchit14]

Agree, But ky has zero deps and works best for browser, Node, Bun etc. Just a suggestion.

[pelikhan]

do you have a migration guide to support httpAgent from https://www.npmjs.com/package/https-proxy-agent ?

[RobertCraigie]

@pelikhan we haven't tested https-proxy-agent directly yet but here's what setting a proxy would look like in a couple different runtimes

Node:

import Anthropic from '@anthropic-ai/sdk';
import * as undici from 'undici';

const dispatcher = new undici.ProxyAgent('http://localhost:8888');

const client = new Anthropic({
  fetch(url, init = {}) {
    return undici.fetch(url, {
      ...(init as unknown as undici.RequestInit),
      dispatcher,
    }) as unknown as Promise<Response>;
  },
});

Bun:

import Anthropic from '@anthropic-ai/sdk';

const client = new Anthropic({
  fetch(url, init) {
    return fetch(url, { ...init, proxy: 'http://localhost:8888' });
  },
});

Deno:

import Anthropic from '@anthropic-ai/sdk';

const httpClient = Deno.createHttpClient({ proxy: { url: 'http://localhost:8888' } });

const client = new Anthropic({
  fetch(url, init) {
    return fetch(url, { ...init, client: httpClient });
  },
});

[pelikhan]

node-openai used this library already

[RobertCraigie]

@pelikhan sorry what do you mean?

[pelikhan]

Here are the docs about using a proxy with node-openai --> https://github.com/openai/openai-node?tab=readme-ov-file#configuring-an-https-agent-eg-for-proxies

[RobertCraigie]

Ah, I think passing the httpAgent client option isn't working right now but the examples I shared should work for now.