improvement: simplify local development by replacing external services with Docker alternativess

[parthjadhao01]

Increasing Access

This improvement increases access by lowering the barrier for new contributors
to set up a local development environment. Currently, contributing to features
like file uploads or email verification requires creating AWS and Mailgun
accounts — both of which may require credit cards and can be confusing for
first-time open source contributors, students, or people in regions where
these services are restricted.

By replacing these with zero-config Docker alternatives (MinIO for S3, MailHog
for email), any contributor can run the full application locally with a single
docker compose up — no accounts, no credit cards, no 30-minute setup detours.

Feature enhancement details

Problem

Setting up the p5.js Web Editor for local development currently requires
creating accounts and generating API keys for external paid/third-party
services — even for basic feature development. This creates unnecessary
friction for new contributors.

The two biggest pain points are:

1. AWS S3 (file uploads)

The contributor_docs/s3_configuration.md guide requires contributors to:

• Create an AWS account
• Create an S3 bucket
• Configure bucket CORS policy
• Create an IAM user with S3 permissions
• Generate and copy access keys into .env

This is a ~30-45 minute detour just to test the file upload feature locally.

2. Mailgun (email)

Email features (signup verification, password reset) require:

• Creating a Mailgun account
• Registering and verifying a domain
• Generating an API key

Currently server/utils/mail.ts throws an error at startup if
MAILGUN_KEY is missing, meaning contributors working on unrelated
features still cannot run the server without a Mailgun key.

---

Proposed Solution

Add local service alternatives to docker-compose-development.yml that
require zero external accounts:

S3 → MinIO

MinIO is a fully S3-compatible object storage server
that runs in Docker. The existing AWS SDK code works with it unchanged —
only the endpoint needs to point to the local container.

minio:
  image: minio/minio
  command: server /data --console-address ":9001"
  ports:
    - '9000:9000'
    - '9001:9001'
  environment:
    - MINIO_ROOT_USER=minioadmin
    - MINIO_ROOT_PASSWORD=minioadmin
  volumes:
    - miniodata:/data

.env.example defaults for local dev:

AWS_ACCESS_KEY=minioadmin
AWS_SECRET_KEY=minioadmin
AWS_REGION=us-east-1
S3_BUCKET=p5-local
S3_ENDPOINT=http://minio:9000
S3_BUCKET_URL_BASE=http://localhost:9000/p5-local

A small init script or startup instructions in the docs would handle
bucket creation and CORS on first run via the MinIO console at
http://localhost:9001.

Mailgun → MailHog

MailHog is a local SMTP server
that captures all outgoing emails and displays them in a web UI at
http://localhost:8025. No emails are actually sent.

mailhog:
  image: mailhog/mailhog
  ports:
    - '1025:1025'  # SMTP
    - '8025:8025'  # Web UI

server/utils/mail.ts would need a small change to use SMTP transport
when a SMTP_HOST env var is set, falling back to Mailgun in production:

SMTP_HOST=mailhog
SMTP_PORT=1025

---

Benefits

• New contributors can run the full application including uploads and
  email with a single docker compose up
• No AWS account, no Mailgun account, no credit card required
• Production behavior is unchanged — these are dev-only defaults
• Significantly lowers the barrier for first-time contributors

---

Related Files

• contributor_docs/installation.md
• contributor_docs/s3_configuration.md
• server/utils/mail.ts
• docker-compose-development.yml

[parthjadhao01]

I would like to work on this if the approach is approved. Please assign this issue to me.