All the OpenAI API Models in 2025: Complete Overview of GPT-5, o-Series, and Multimodal AI

GPT-5 is now the flagship general-purpose model.

It’s August 8, 2025, and OpenAI’s model lineup has expanded into a highly segmented portfolio, with GPT-5 at the very top for general-purpose and agentic use. Available in Standard, Mini, and Nano versions, it offers longer context windows—up to 256,000 tokens in certain configurations—native multimodal input (text, image, audio, video), integrated tool usage, persistent memory, and customization options such as embedded calendars or email integrations. Pricing varies by variant, with Mini and Nano designed to significantly reduce cost while maintaining competitive performance. GPT-5 is designed to be the default choice when you need maximum versatility and capability from a single model.

GPT-4.1 remains a robust workhorse for most development needs.

Released in April 2025, the GPT-4.1 family—comprising GPT-4.1, GPT-4.1 Mini, and GPT-4.1 Nano—was built to improve on GPT-4o’s performance in coding, instruction-following, and long-context understanding. The family maintains a balance between cost-efficiency and breadth of capability, making it a common standard for production workloads. Long-context support can extend into the million-token range with specific tooling, enabling it to handle complex document workflows and large codebases. GPT-4.1 Mini delivers nearly the same output quality as GPT-4o at a fraction of the price, while Nano focuses on speed and economy.

GPT-4o still defines multimodality for day-to-day workflows.

GPT-4o (“Omni”) remains a leader in native multimodal processing, seamlessly handling text and vision inputs in a single prompt. GPT-4o Mini provides a lighter, faster, and cheaper option for less demanding multimodal tasks. These models are ideal when projects require the model to interpret or generate text while referencing images, or to process rich media in an integrated environment. The “chatgpt-4o-latest” alias keeps developers aligned with ongoing improvements without changing model IDs.

Realtime and audio capabilities redefine interactive AI.

For voice-based and low-latency applications, the Realtime API supports bidirectional streaming between the client and GPT-4o-class models. Developers can integrate both speech-to-text and text-to-speech directly, enabling natural conversations with AI agents. The latest STT models—gpt-4o-transcribe and gpt-4o-mini-transcribe—offer superior transcription accuracy and multilingual support. The gpt-4o-mini-tts model provides expressive, controllable speech synthesis. Together, they enable fluid, voice-driven experiences without leaving the OpenAI stack.

GPT-Image-1 consolidates image creation and editing.

Image generation has moved to gpt-image-1, replacing the need for DALL·E in the API. This model supports high-resolution generation, inpainting, and advanced editing workflows. Developers migrating from DALL·E 3 will find similar endpoint patterns with expanded parameters for control. Its integration with other GPT models means a single API can now deliver cohesive text, vision, and creative image outputs.

Reasoning-focused models raise the ceiling for complex tasks.

The o-series models—o3, o4-mini, and the earlier o1 line—are optimized for deep reasoning. They allocate more compute time to internal “thinking” before producing answers, yielding improved performance in multi-step tasks, coding challenges, mathematical reasoning, and structured problem-solving. o3-pro and o4-mini are particularly strong in tool usage, making them valuable for agentic architectures that must execute functions or orchestrate multi-tool workflows. Access to the highest tiers is tied to an account’s usage level.

Deep research capabilities enable autonomous information gathering.

With o3-deep-research and o4-mini-deep-research, OpenAI extends reasoning into multi-step web and document research. These models break a query into sub-questions, search across sources, read at scale, and synthesize findings with citations. They are designed for extended jobs, and the API allows progress streaming so clients can surface partial results in real time.

Specialized tool-use models target search and UI control.

Preview search-focused models—gpt-4o-search-preview and its mini version—are tuned to parse search queries and execute retrieval steps. For GUI automation, the computer-use-preview model works with the Computer Use tool to “see” interfaces and act on them via simulated clicks and keyboard inputs. This opens the door to agents that can navigate software environments or perform browser-based tasks without manual scripting.

Embeddings power search, clustering, and retrieval-augmented generation.

The text-embedding-3-large and text-embedding-3-small models remain the backbone for semantic search, clustering, and RAG pipelines. Large maximizes multilingual and domain accuracy, while Small prioritizes cost-efficiency. They fit directly into vector database workflows and are essential for applications that require rapid matching and contextual recall.

Moderation models maintain trust and safety in production.

omni-moderation-latest offers unified moderation across text and images, detecting unsafe or noncompliant content across multiple categories. For lighter text-only scenarios, text-moderation-latest remains available. Moderation calls are free in the API, ensuring developers can keep robust content filtering in place without financial friction.

The Responses API is now the integration hub for multi-tool agents.

While Chat Completions remains supported, the Responses API has become the central integration point for multi-modal, multi-tool agent workflows. It allows a single request to combine reasoning models, web search, file search, and computer use in orchestrated sequences. The API’s schema is designed to streamline tool invocation and structured output.

Deprecations and open-weight models mark important ecosystem shifts.

OpenAI maintains a Deprecations page to track model retirements, such as the phase-out of GPT-4.5 earlier this year. Keeping an eye on this resource ensures timely migrations. Separately, the release of open-weight models—gpt-oss-120B and gpt-oss-20B—under Apache 2.0 expands the ecosystem for developers who need self-hosted, customizable reasoning systems. These are not served via API, but their availability signals a broader commitment to AI accessibility.

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