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

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 .This creates unnecessary
friction for 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

Start with docker-compose-development.yml, contributor_docs/installation.md, contributor_docs/s3_configuration.md, and server/utils/mail.ts. Run the existing development Compose setup and trace the upload and email configuration paths. Done means local development can use the documented Docker services without AWS or Mailgun credentials while production behavior remains unchanged.