# Host graphql api with Express: stored input and output artifacts

Deploy a graphql api built with Express on Ample using the generated downloads pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL, a private S3-compatible bucket holds objects with credentials delivered as encrypted environment variables. Verified on Express: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). Not separately tested: your export formats, retention policy and entitlement model; treat the graphql api-specific behavior as your application code.

## Representative Queries
- Host graphql api with Express: stored input and output artifacts
- Where can I host GraphQL API built with Express?
- I need an input/output artifact contract, object metadata and access boundaries.

## Resource Requirements
- primitive:compute
- primitive:postgres
- primitive:s3-compatible-object-storage

## Infrastructure Requirements
- **Compute**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
- **Postgres**: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.
- **S3-compatible object storage**: Buckets are S3-compatible with issued credentials; PutObject and GetObject are verified by canary. Other S3 operations are not verified.

## Workflow Steps
1. **Build and start**: npm install, npm run build --if-present, npm run start on the node-22 template. The server must bind 0.0.0.0 on PORT.
2. **Implement the pattern on PostgreSQL**: The fixture's module implements generated downloads: an export query rendered to a CSV artifact stored with metadata in a private bucket and returned only to an authorized caller (401 without token, export=ok rows=3). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.
3. **Wire object storage**: Create the bucket(s), then pass endpoint, region, bucket and keys as --env values. Use path-style addressing. Keep private data in an unpublished bucket.
4. **Deploy**: Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked). Re-running with no change is a no-op.
5. **Verify**: Fetch the live URL and the pattern self-test route(s) (/p/generated-downloads) from the example; then run your own checks. On failure read `ample logs  --kind build` then `--kind runtime`.

## Input Schema
- **env**: Encrypted environment variables (bucket credentials, secrets)
- **name**: App name
- **path**: Project directory or ample.toml service
- **release_command**: Migration command run before activation

### Required Fields
- env
- name
- path

## Examples
- **Express pattern fixture**: Multi-pattern Express app whose generated downloads module was checked live; the module is under tests/deploy-canaries/_pattern-modules.

## Success Checks
1. **App responds** on its public URL
2. **Generated-downloads self-test**: 401 without token, export=ok rows=3

## Limitations
- Verified on the node-22 template at s-1vcpu-1gb with the example fixture; other sizes and templates are not verified.
- The graphql api itself (your export formats, retention policy, and entitlement model) is application code and was not separately tested.

## Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 10.00
- **Basis**: size prices from pricing.toml
- **Components**:
   - app server: size s-1vcpu-1gb
   - managed PostgreSQL database: size s-1vcpu-1gb

## Evidence Summary
- **Canary run**: Express pattern fixture deployed on Ample; checks passed for generated-downloads.
- **Observed at**: 2026-09-21T02:34:39Z

## Next Actions
- **Browse the catalog index**: GET /v1/catalog
- **Search published recipes**: POST /v1/catalog/search
- **Prepare a side-effect-free deployment plan for an authorized project**: POST /v1/catalog/plan
- **Read existing agent authentication setup**: GET /mcp/setup
- **Browse GraphQL API**: GET /v1/catalog/nodes/workload%3Agraphql-api
- **Browse Express**: GET /v1/catalog/nodes/stack%3Aframework-express
- **Browse Generated downloads**: GET /v1/catalog/nodes/pattern%3Agenerated-downloads
- **Browse Deploy API**: GET /v1/catalog/nodes/intent%3Adeploy-api