---
title: "Foundation"
description: "Shared primitives, validation, security, and diagnostics used across Playstack capabilities."
tags: ["packages","foundation"]
---

Foundation packages establish the contracts every other Playstack capability can share without pulling a framework, database, or vendor toward the application core.

## Packages

| Package                                                                 | Plan                        | Responsibility                                                           |
| ----------------------------------------------------------------------- | --------------------------- | ------------------------------------------------------------------------ |
| [`@playstack/core`](/docs/packages/foundation/core)                     | <PlanTierDot tier="free" /> | Errors, results, clocks, identifiers, and operation context.             |
| [`@playstack/errors`](/docs/packages/foundation/errors)                 | <PlanTierDot tier="free" /> | Runtime-neutral error reporting and safe fan-out.                        |
| [`@playstack/errors-react`](/docs/packages/foundation/errors-react)     | <PlanTierDot tier="pro" />  | React error reporting context and resettable boundaries.                 |
| [`@playstack/nest-errors`](/docs/packages/foundation/nest-errors)       | <PlanTierDot tier="pro" />  | NestJS error reporter injection and exception filtering.                 |
| [`@playstack/validation`](/docs/packages/foundation/validation)         | <PlanTierDot tier="free" /> | Shared schemas and portable HTTP validation errors.                      |
| [`@playstack/crypto`](/docs/packages/foundation/crypto)                 | <PlanTierDot tier="free" /> | Web Crypto operations with explicit key ownership.                       |
| [`@playstack/prisma-runtime`](/docs/packages/foundation/prisma-runtime) | <PlanTierDot tier="pro" />  | Explicit runtime selection for generated Prisma clients.                 |
| [`@playstack/skills`](/docs/packages/foundation/skills)                 | <PlanTierDot tier="free" /> | Versioned repository guidance for agents composing Playstack packages.   |
| [`@playstack/lint`](/docs/packages/foundation/lint)                     | <PlanTierDot tier="free" /> | Deterministic checks for package and application integration boundaries. |

## Start here

Most applications begin with `@playstack/core`. Add validation or crypto only when a capability needs those contracts, and keep framework bindings at the outside edge of the application. Tooling remains independently adoptable: the [CLI](/docs/cli), Skills corpus, and lint rules do not enter the runtime graph.

## Localization previews

The independently adoptable [i18n core](/docs/packages/foundation/i18n), [React binding](/docs/packages/foundation/i18n-react) and [Nest binding](/docs/packages/foundation/nest-i18n) provide locale policy, typed catalogs and application composition. All three are classified Free under the Laravel localization baseline. The [UI localization guide](/docs/frameworks/ui-localization) covers shared English artifacts and host-owned translations.