# OpenAPI-first design — Use case > Draft an OpenAPI spec; the gateway turns it into a governed proxy. One-click generation, contract-driven mocks, and partner-ready portals — without writing service code. *Developers · Design · For developers* ## Spec first. Proxy second. Service third. Apinizer's API Designer takes an OpenAPI draft, generates a governed proxy, ships a mock, and lists the endpoint in the partner portal — before any service exists. [Five-minute quickstart](https://apinizer.com/developers/quickstart) · [Open API Designer](https://apinizer.com/products/api-designer) --- ## The problem *The problem* ### Most teams write specs after they ship. That's how contracts drift. Engineers ship the service, then write the OpenAPI to match — and the spec ages out the first time a feature ships without a doc update. Apinizer flips the order: the spec is the source of truth. Proxy, mock, portal, contract test — all derived from it. Drift is impossible because there's nowhere for it to live. --- ## Capabilities ### Spec authoring in-platform Draft OpenAPI 3.x in the platform. Reviewers leave comments in place; the spec is the working document, not the export. ### One-click proxy generation Generate a governed proxy from the spec. Auth, rate limits, validation defaults applied — engineers tune from a starting point that's already correct. ### Contract-driven mocks Mock API generated from the same spec. Frontend, partners, and contract tests unblock immediately. ### Validation in production Request and response validation enforced at the gateway against the spec. Bad payloads rejected at the edge with clean errors. ### Spec governance Required fields, naming conventions, deprecation hygiene — checked on every PR. The platform team encodes the rules once; every team gets the lift. ### Multi-protocol bridges OpenAPI fronting a SOAP backend, a gRPC service, or a stored procedure — the proxy translates the contract on the way through. --- ## Real-world examples ### Banking **Scenario:** Istanbul bank ships every new endpoint as a spec PR first **Outcome:** Spec lands in Git; CI runs lint and policy checks. On merge, the proxy and mock generate; partners onboard against the mock the same day. ### Manufacturing **Scenario:** Munich OEM unifies 14 plant teams on one spec template **Outcome:** Every plant's APIs follow the same naming, the same auth, the same versioning. New plant onboarded in days, not quarters. ### Public sector **Scenario:** Stockholm agency enforces national-standard fields on every spec **Outcome:** Required citizen-ID format, mandatory consent flag, audit-tag — checked in CI. Specs that miss a required field fail review. ### Telecom **Scenario:** Madrid carrier auto-generates partner portal pages from spec **Outcome:** Portal pages, code samples, and contract tests all derived from the spec. Partner docs never go stale. ### Retail **Scenario:** Amsterdam marketplace runs validation at the edge to reject bad payloads **Outcome:** Pre-existing services kept doing partial validation; Apinizer's spec-driven validation rejects bad calls before backends see them. ### Insurance **Scenario:** Milan insurer translates legacy SOAP backends through OpenAPI proxies **Outcome:** Designer specs map to SOAP operations. Modern consumers see clean REST; the legacy backend never changes. ### Healthcare **Scenario:** Prague hospital ships FHIR-aligned specs as the contract source **Outcome:** FHIR resources mapped in the spec; downstream EHR translation handled by the proxy. Vendor connectors interoperate by construction. ### Government **Scenario:** Baku ministry enforces deprecation hygiene in spec linting **Outcome:** Deprecation policy: each operation must declare a sunset date. CI rejects specs without one; the ministry catches debt before it ships. --- ## Recommended modules - [API Designer](https://apinizer.com/products/api-designer) — Spec-first authoring with one-click proxy and mock generation. - [API Gateway](https://apinizer.com/products/api-gateway) — Runtime that validates against the spec on every request. - [Mock API](https://apinizer.com/products/mock-api) — Contract-driven mocks generated from the same OpenAPI document. - [API Portal](https://apinizer.com/products/api-portal) — Auto-generated partner portal pages from the spec. --- ## Resources - [OpenAPI-first overview](https://docs.apinizer.com/en) — Spec authoring, proxy generation, mock generation, validation behavior. - [API Designer product](https://apinizer.com/products/api-designer) — Where specs live, get reviewed, and ship from. - [APIops manifests](https://apinizer.com/developers/apiops) — Promote specs across environments without changes. - [API Reference](https://apinizer.com/developers/api-reference) — Browse every generated reference for Manager and APIops. - [Analytics Engine](https://apinizer.com/products/analytics-engine) — Per-spec, per-version traffic and validation telemetry. - [Architecture overview](https://docs.apinizer.com/en/concepts/architecture) — Where Designer, Gateway, Mock, and Portal compose. --- ## Related use cases - [API lifecycle management](https://apinizer.com/solutions/api-lifecycle-management) — For platform teams - [APIops (CI/CD)](https://apinizer.com/solutions/apiops) — For developers - [Mock APIs](https://apinizer.com/solutions/mock-apis) — For developers - [Connector library (15+)](https://apinizer.com/solutions/connector-library) — For developers --- ## Next step *Spec is the contract* **Ship from OpenAPI. Govern by default.** A 30-minute walkthrough — draft, generate, mock, govern — on a Kubernetes of your choice. [Book a Demo](https://calendly.com/apinizer/15min) · [Read the docs](https://apinizer.com/developers/docs) --- ## Links - Products: https://apinizer.com/products - AI Gateway: https://apinizer.com/products/ai-gateway - Solutions: https://apinizer.com/solutions - Pricing: https://apinizer.com/pricing - Developers: https://apinizer.com/developers - Documentation: https://docs.apinizer.com/index-en - Blog: https://apinizer.com/blog - Contact: https://apinizer.com/company/contact © 2026 Apinizer. All rights reserved.