Ace Data Cloud Facilitator X402

Official verification and settlement implementation for the x402 v2 protocol, built on the Python SDK (x402==2.16.0). The canonical production endpoint is https://facilitator.acedata.cloud. The temporary validation candidate was retired after the official-v2 production cutover completed in July 2026.

Production rails

Scheme	Network	CAIP-2 identifier	Asset
exact	Base mainnet	eip155:8453	Circle USDC
upto	Base mainnet	eip155:8453	Circle USDC through Permit2
exact	SKALE Base	eip155:1187947933	Bridged USDC
exact	Solana mainnet	solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp	SPL USDC

Solana devnet support exists behind configuration and is disabled by default. It is a testnet compatibility option, not a production rail.

API

• GET /healthz: liveness and readiness probe.
• GET /supported: official facilitator kinds, extensions, and signer addresses.
• POST /verify: validate and reserve a v2 payment authorization.
• POST /settle: settle a verified authorization. This endpoint requires X-Settlement-Token.
• GET /.well-known/x402: facilitator metadata.
• GET /discovery/resources: paginated CAIP-2 resource catalog.
• GET /list: compatibility redirect to discovery.

The official SDK handles protocol parsing, signature verification, simulation, and transaction construction. This service adds:

• PostgreSQL-backed authorization and settlement state;
• per-network PostgreSQL advisory locks across two replicas;
• prepared transaction persistence before broadcast;
• deterministic recovery and reconciliation;
• asset and recipient allowlists;
• authenticated settlement and replay protection.

Configuration

Database settings:

• PGSQL_HOST, PGSQL_PORT, PGSQL_USER, PGSQL_PASSWORD
• PGSQL_DATABASE_FACILITATOR

Core settings:

• APP_ENV, APP_SECRET_KEY, ALLOWED_HOSTS
• X402_SETTLE_TOKEN
• X402_FACILITATOR_PUBLIC_URL
• X402_SETTLEMENT_LEASE_SECONDS
• X402_PREPARED_MAX_AGE_SECONDS
• X402_TX_TIMEOUT_SECONDS

Each enabled rail requires its RPC URL, signer key/address, approved asset, and approved recipient. See docs/migration.md for the complete Base, SKALE, Solana, discovery, migration, cutover, and rollback configuration.

Development

poetry install
poetry run python manage.py migrate
poetry run python manage.py runserver 0.0.0.0:8008

Run validation:

poetry run pytest -q
poetry run ruff check .
poetry run ruff format --check .

Local container:

docker compose build
docker compose up

Compose loads the gitignored .env when present. It can still build without the file in CI, but payment rails require their configured RPC, signer, asset, and recipient values before runtime use.

The shared image runs as non-root UID/GID 10001 and serves ASGI with Uvicorn on port 8000.

Delivery

• .github/workflows/ci.yaml: PR test, lint, and Docker build.
• .github/workflows/deploy.yaml: manual production build and deployment from main through deploy/run.sh.

Production deployment uses a Recreate strategy to prevent old and official settlement semantics from overlapping. The runbook quiesces traffic, checks legacy records, applies migrations, deploys two replicas, starts reconciliation, and rolls back the Deployment and CronJob if validation fails.

See docs/migration.md for the completed official-v2 migration record and rollback constraints.