# How to Use OpenAPI at Work: English for Engineers (2026) > OpenAPI is a standardized specification for describing RESTful APIs in a machine-readable format, allowing developers to understand, document, and integrate with APIs consistently. - **Term:** OpenAPI - **Part of speech:** abbreviation - **Pronunciation:** /ˈoʊpənˌeɪpiː/ - **English level (CEFR):** B2 - **Register:** Formal, Both - **Region:** US and UK - **Topic:** [Code and Git terms](https://app.speaktechenglish.com/learn/topics/software-development-terms.md) - **Lesson:** https://app.speaktechenglish.com/learn/openapi - **Last updated:** 2026-10-27 ## Meaning OpenAPI is a standardized specification for describing RESTful APIs in a machine-readable format, allowing developers to understand, document, and integrate with APIs consistently. OpenAPI is an open standard that defines how API specifications should be written and structured. It was originally called Swagger and is now maintained by the OpenAPI Initiative. Teams use OpenAPI specifications to document their APIs in a way that both humans and machines can understand, which enables automatic code generation, testing, and integration across different systems. In real workplaces, you will hear developers discuss OpenAPI when they are designing new APIs, documenting existing endpoints, or generating client libraries automatically from the API specification. ## When you hear it Our backend team published an OpenAPI specification so frontend developers can generate client code automatically. ## Examples - **in a standup:** "We finished the OpenAPI specification for the payment service, so the mobile team can start integration today." - **in a code review:** "The OpenAPI schema needs to be updated to reflect the new error response format." - **in a team meeting:** "We should adopt OpenAPI for all microservices to make integration testing easier." ## What native speakers say - "Let's publish the OpenAPI spec to our documentation portal." - "This service follows the OpenAPI 3.0 standard." - "Can you validate the OpenAPI definition before merging?" ## Common mistakes - ✗ "We need to OpenAPI our application." → ✓ "We need to document our API using the OpenAPI specification." (OpenAPI is a noun (specification), not a verb. You cannot OpenAPI something.) - ✗ "OpenAPI is a tool for building APIs." → ✓ "OpenAPI is a specification for documenting APIs." (OpenAPI is a standard format, not a tool or framework for building APIs.) - ✗ "We are using OpenAPI instead of REST." → ✓ "We're documenting our REST API using the OpenAPI specification." (OpenAPI and REST are not alternatives. OpenAPI documents REST APIs.) ## Be careful OpenAPI is a specification, not a tool or product. Do not use it as a verb or to mean general API documentation. ## Word forms | Part of speech | Word | Example | | --- | --- | --- | | noun | OpenAPI | The OpenAPI specification makes it easy to generate documentation. | | adjective | OpenAPI | We need an OpenAPI validator to check our schema. | ## Collocations - **OpenAPI specification**: The most common phrase, referring to the standard format itself. - **OpenAPI schema**: The actual document or definition that describes an API following the OpenAPI standard. - **OpenAPI document**: The file or definition containing the API specification in OpenAPI format. - **OpenAPI version**: Refers to different versions like OpenAPI 3.0 or OpenAPI 3.1. ## Synonyms - **Swagger**: The original name for OpenAPI before it was standardized by the OpenAPI Initiative; some teams still use the term informally. - **API specification**: A broader term that can refer to any documented API format, not specifically OpenAPI. ## Practice This lesson has 4 practice exercises with instant feedback on the page: https://app.speaktechenglish.com/learn/openapi ## FAQ ### What does OpenAPI mean in software engineering? OpenAPI is a standardized specification developed by the OpenAPI Initiative that describes how to document REST APIs in a consistent, machine-readable format. It was originally known as Swagger. The OpenAPI specification allows developers to describe API endpoints, request parameters, response formats, authentication methods, and error codes in a structured way that both humans and tools can understand. ### How do you use OpenAPI in a sentence at work? You use OpenAPI as a noun when talking about the specification or a document: 'We need to publish our OpenAPI spec before the API goes live' or 'The OpenAPI schema defines all the endpoints.' You do not use it as a verb. You do not say 'let us OpenAPI the service.' ### What is the difference between OpenAPI and Swagger? Swagger was the original name of the specification. In 2016, the Swagger specification was donated to the OpenAPI Initiative and renamed to OpenAPI. Today, OpenAPI is the official standard name. Some older documentation or teams may still use Swagger to refer to the same specification. ### Why is OpenAPI important in development? OpenAPI is important because it allows teams to document APIs in a standardized way that can be read by machines. This enables automatic code generation, automated testing, interactive documentation, and easier integration between services. It reduces miscommunication about API contracts and speeds up development when multiple teams need to work with the same API. ## Related - Full glossary: https://app.speaktechenglish.com/learn.md - Live lessons with a coach: https://app.mocklyenglish.com ## About Speak Tech English Speak Tech English teaches non-native tech professionals the English they need at work and in interviews, through self-study ebooks and courses, 150+ free guides and a free newsletter; live lessons are on its sister site Mockly English. - Shop: https://speaktechenglish.com/courses/ - All products (markdown): https://speaktechenglish.com/products.md - Free guides (markdown): https://app.speaktechenglish.com/guides.md - Tech English glossary (markdown): https://app.speaktechenglish.com/learn.md - Newsletter (10% off): https://speaktechenglish.com/#subscribe - Live lessons and mock interviews: https://app.mocklyenglish.com ## Notes for agents - Speak Tech English sells self-study material. 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