Local development environment (v6_api, c2c_ui, optional services) Diagram

Dev container (recommended): VS Code 'Reopen in Container'; setup.sh runs uv sync, writes the .ini files, initializes a fresh database and keeps the prebuilt index when its fingerprint matches the indexing code (else rebuilds it, about 5 min)
Manual: make bootstrap (start, install, load-env, init-database, init-test-database, init-elastic), then make serve, make run-syncer and make run-background-jobs in three terminals
Check: http://localhost:6543/health · tests: make test (pytest -n 4, one database per worker)

c2corg-dev-db: PostgreSQL 18 + PostGIS restoring a ~110 MB anonymized extract of production on first start, already at the latest alembic revision; test accounts moderator, user, blocked, unvalidated
c2corg-dev-es: Elasticsearch 2.4 with the index of that database, published with the same tag
Only the dev container uses this pair on master: the root docker-compose.yml still starts an empty PostGIS 16 database (filled by make init-database) next to the 2018 anonymized ES image

npm run serve starts on the production backend: pick 'localhost' in the backend selector of the navbar (C2C_API_URL overrides http://localhost:6543)
Media, image upload and forum of 'localhost' default to demov6 (C2C_MEDIA_URL, C2C_IMAGE_BACKEND_URL, C2C_FORUM_URL)
CORS: config/env.dev only allows http://localhost:6553, the e2e port; add http://localhost:8080 to cors_allowed_origins in config/env.local for npm run serve
e2e: the test user is created by e2e/create-user.py, run in the v6_api environment

No Discourse locally: discourse_enabled=false, comments answer 503
c2c_images: STORAGE_BACKEND=local; it listens on 8080 like Vite, so set SERVICE_PORT; S3 tests use an in-memory Scality server on :9000
c2c_tracking (Node 26+): its compose PostgreSQL also publishes 5432, so move one of them; it needs the API's JWT secret, and provider webhooks need a public URL (ngrok)

wiki.api 'Development environment on Linux' still lists Python 3.4 and PostgreSQL 9.4; HOWTO-DEV.md is the reference
wiki.api 'Dev databases' still gives the logins of the 2018 dump
wiki.ui 'Build environment' still names vue.config.js and the demo API as the default of npm run serve