Boundary Boundary alpha
Docs Why Boundary Blog Home
Get Started

Foundation library providing shared utilities used by all other Boundary libraries. Contains no shell layer — everything is pure functions.

Key namespaces

Namespace Purpose

boundary.core.validation

Malli-based validation framework with error codes, messages, and "did you mean?" suggestions

boundary.core.validation.registry

Central registry for validation rules across libraries

boundary.core.validation.coverage

Validation coverage reporting and analysis

boundary.core.validation.snapshot

Snapshot-based validation testing

boundary.core.utils.case-conversion

kebab-case / snake_case / camelCase conversions

boundary.core.utils.type-conversion

UUID, Instant, BigDecimal string conversions

boundary.core.utils.pii-redaction

PII filtering for logs and error reports

boundary.core.utils.validation

Generic validation helpers

boundary.core.interceptor

Interceptor pipeline runner (enter/leave/error phases)

boundary.core.interceptor-context

Interceptor context creation and management

boundary.core.config.feature-flags

Feature flag evaluation logic

Case conversion

The most commonly used utilities across the entire monorepo:

(require '[boundary.core.utils.case-conversion :as cc])

;; Persistence boundary — DB record → Clojure entity
(cc/snake-case->kebab-case-map db-record)

;; Persistence boundary — Clojure entity → DB insert/update
(cc/kebab-case->snake-case-map entity)

;; HTTP boundary — Clojure entity → JSON response
(cc/kebab-case->camel-case-map entity)

;; HTTP boundary — JSON request → Clojure map
(cc/camel-case->kebab-case-map api-input)

Validation framework

(require '[boundary.core.utils.validation :as validation])

;; Generic validation with transformation
(validation/validate-with-transform SomeSchema data mt/string-transformer)
;=> {:valid? true :data transformed-data}
;=> {:valid? false :errors validation-errors}

;; CLI argument validation
(validation/validate-cli-args CliSchema args cli-transformer)

Interceptor pipeline

The interceptor system supports enter/leave/error phases, used by both HTTP and service layers:

(require '[boundary.core.interceptor :as ic])

;; Enter phases run forward, leave phases run in reverse
(ic/run-pipeline initial-ctx [interceptor1 interceptor2 interceptor3])
;; Enter order:  int1 → int2 → int3
;; Leave order:  int3 → int2 → int1

Important conventions

  • All functions must be pure — no I/O, no logging, no side effects

  • This library has no ports.clj or shell/ — it’s entirely functional core

  • Only dependencies: org.clojure/clojure and metosin/malli

  • All other Boundary libraries depend on core

Testing

clojure -M:test:db/h2 :core
clojure -M:test:db/h2 --focus-meta :unit   # All core tests are :unit