Generating OpenAI GPT3 completions

Generate GPT text completions using OpenAI and Supabase Edge Functions.

OpenAI provides a completions API that allows you to use their generative GPT models in your own applications.

OpenAI's API is intended to be used from the server-side. Supabase offers Edge Functions to make it easy to interact with third party APIs like OpenAI.

Setup Supabase project#

If you haven't already, install the Supabase CLI and initialize your project:

supabase init

Create edge function#

Scaffold a new edge function called openai by running:

supabase functions new openai

A new edge function will now exist under ./supabase/functions/openai/index.ts.

We'll design the function to take your user's query (via POST request) and forward it to OpenAI's API.

import 'xhr_polyfill'
import { serve } from 'std/server'
import { CreateCompletionRequest } from 'openai'

serve(async (req) => {
  const { query } = await req.json()

  const completionConfig: CreateCompletionRequest = {
    model: 'text-davinci-003',
    prompt: query,
    max_tokens: 256,
    temperature: 0,
    stream: false,
  }

  return fetch('https://api.openai.com/v1/completions', {
    method: 'POST',
    headers: {
      Authorization: `Bearer ${Deno.env.get('OPENAI_API_KEY')}`,
      'Content-Type': 'application/json',
    },
    body: JSON.stringify(completionConfig),
  })
})

Note that we are setting stream to false which will wait until the entire response is complete before returning. If you wish to stream GPT's response word-by-word back to your client, set stream to true.

Create OpenAI key#

You may have noticed we were passing OPENAI_API_KEY in the Authorization header to OpenAI. To generate this key, go to https://platform.openai.com/account/api-keys and create a new secret key.

After getting the key, copy it into a new file called .env.local in your ./supabase folder:

OPENAI_API_KEY=your-key-here

Run locally#

Serve the edge function locally by running:

1supabase functions serve --env-file ./supabase/.env.local --no-verify-jwt

Notice how we are passing in the .env.local file.

Use cURL or Postman to make a POST request to http://localhost:54321/functions/v1/openai.

1curl -i --location --request POST http://localhost:54321/functions/v1/openai \
2  --header 'Content-Type: application/json' \
3  --data '{"query":"What is Supabase?"}'

You should see a GPT response come back from OpenAI!

Deploy#

Deploy your function to the cloud by runnning:

1supabase functions deploy --no-verify-jwt openai
2supabase secrets set --env-file ./supabase/.env.local

Go deeper#

If you're interesting in learning how to use this to build your own ChatGPT, read the blog post and check out the video: