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HTTP Model

zio-http-model is a pure, zero-dependency HTTP data model for building HTTP clients and servers. It provides immutable types representing all HTTP concepts: requests, responses, headers, URLs, paths, query parameters, methods, status codes, versions, cookies, and forms. The module separates protocol concerns (representing HTTP messages) from effect concerns (actually sending/receiving them), enabling portable, testable HTTP code across any Scala application.

Core Capabilities​

The HTTP model is organized into two complementary modules:

HTTP Model — Pure Data Types​

The foundation of the HTTP model: immutable data types representing HTTP requests, responses, and all associated primitives. No effects, no I/O, no coupling to specific runtimes.

Key types: Request, Response, URL, Headers, Body, Method, Status, Version, Scheme, Path, QueryParams, ContentType, RequestCookie, ResponseCookie, Form.

Use this when: Building request/response data structures, parsing HTTP primitives, serializing messages for storage or caching, or sharing HTTP types across effect systems.

Schema-Based Typed Access — Type-Safe Extraction​

Extension methods that add type-safe, validated extraction of query parameters and headers to the core HTTP model. Automatically decode string values to typed objects using schema-based decoding with comprehensive error reporting.

Key features: Typed QueryParams#query[T], Headers#header[T], Request#query[T] methods with schema-based decoding, automatic error reporting for missing or malformed values, support for 11 primitive types and custom types via Schema[T].

Use this when: You need to extract and validate query parameters or headers with type safety, decode values to domain types, or provide clear error messages for malformed input.

How They Work Together​

  1. Build pure HTTP data using the core HTTP model types
  2. Add type-safe extraction with schema-based extension methods
  3. Hand off to an HTTP client/server library (ZIO HTTP, Akka, Play, etc.) for the actual I/O work

This separation keeps your domain logic portable and testable while maintaining full expressiveness for HTTP interactions.

Getting Started​

Start with the HTTP Model to understand the core data types and how they compose. Then explore Schema-Based Typed Access to learn how to safely extract and validate HTTP parameters and headers.

Modules: