Type Alias AmplifyHostingConstructProps

BYO S3 bucket for build cache storage. Creates one if not provided.

Overrides for the adjustable AWS Service Quotas this distribution draws on — cacheBehaviors (CloudFront behaviors per distribution), edgeFunctions (Lambda@Edge associations), and headerPolicies (response-headers policies per account). Omitted fields use AWS defaults.

Set a field ONLY to match a quota increase AWS has actually granted: synth cannot verify your real quota, so an over-set value does not raise the AWS ceiling — it just moves the failure from a clear synth error to an opaque CloudFormation rollback at deploy.

Bring-your-own ResponseHeadersPolicy. When provided, the construct skips creating its own policy — use this to share a single policy across multiple hosting stacks and avoid the account-level limit (default 20, max 200 via service-quota increase).

Create a shared policy once (e.g. in a shared-infra stack):

const sharedPolicy = new ResponseHeadersPolicy(sharedStack, 'SharedPolicy', { ... });
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Then import by ID in each hosting stack:

cdn: { responseHeadersPolicy: ResponseHeadersPolicy.fromResponseHeadersPolicyId(this, 'Imported', policyId) }
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Default TTL for SSR/compute cache behaviors when the origin response does not include a Cache-Control header. Set this to enable CloudFront edge caching of SSR responses and improve hit ratio.

When set, SSR responses without an explicit Cache-Control header are cached at the edge for this duration. The origin can always override via s-maxage or no-store.

ARN of an existing WAFv2 WebACL to associate with the CloudFront distribution. Use this when you manage WAF rules externally (e.g. via a shared security account) or need advanced WAF features beyond the built-in waf.enabled rate-limiting.

Takes precedence over waf.enabled — when set, the built-in WAF construct is not created.

Additional environment variables to inject into all compute Lambda functions. Merged with (and overrides) any environment variables declared in the deploy manifest's compute resources.

Reserved concurrent executions for the image-optimization Lambda. Default: undefined (no reservation).

Historically this was hardcoded to 10, which broke cdk deploy on fresh AWS accounts: the default account-level unreserved-concurrency limit is 10, so reserving all 10 for image-opt drops the account below its required minimum and Lambda rejects the stack with a 400. Defaulting to no reservation keeps deploys working out of the box while still letting operators cap image-opt explicitly.

Provisioned concurrency for the SSR Lambda (cold-start elimination). When > 0, the construct creates a live alias with this many always-warm execution environments and points the SSR REST API integration at the alias. Default: undefined (no provisioning).

Lambda timeout. Accepts either a cdk.Duration (preferred) or a number of seconds for ergonomics — the L3 normalizes both to Duration before handing them to the Lambda construct. A plain number used to slip through the type at the user-facing API surface (e.g. when consumed via JS-compiled wrappers) and crash synth deep inside aws-cdk-lib with props.timeout.toSeconds is not a function. Coercing here makes that surface forgiving.

4.1 — OpenTelemetry env hooks for SSR / image-opt / revalidation Lambdas.

2.1 — synthetic warmup schedule.

Path to a custom 404 HTML file (relative to project root).

Path to a custom 500 HTML file (relative to project root).

How long to honor old build cookies (seconds). Default: 86400 (24h)

Advisory hint used at synth to warn when deploy cadence ≥ retention (#480).

Resources for the Lambda that uploads static assets to S3 (CDK's BucketDeployment). CDK defaults this Lambda to 128 MB memory and a 512 MiB /tmp — too small for large static sites, which then OOM or run out of disk with an opaque CloudFormation error at deploy time. The L3 raises the defaults to 1024 MB / 1024 MiB; override here if a very large build still hits the ceiling.

3.3 — opt-in daily S3 inventory of builds/.