Modern AI applications, whether voice‑first experiences or building large software systems, rarely fit into a single prompt. Real work unfolds over time: maintaining context, following instructions, invoking tools, and adapting as requirements evolve. When these foundations break down through latency spikes, instruction drift, or unreliable tool calls, both user conversations and developer workflows are impacted.

OpenAI’s latest models address this shared challenge by prioritizing continuity and reliability across real‑time interaction and long‑running engineering tasks. Starting today, GPT-Realtime-1.5, GPT-Audio-1.5, and GPT-5.3-Codex are rolling out into Microsoft Foundry. Together, these models reflect the growing needs of the modern developer and push the needle from short, stateless interactions toward AI systems that can reason, act, and collaborate over time.

GPT-5.3-Codex at a glance

GPT‑5.3‑Codex brings together advanced coding capability with broader reasoning and professional problem solving in a single model built for real engineering work. It unifies the frontier coding performance of GPT-5.2-Codex with the reasoning and professional knowledge capabilities of GPT5.2 in one system. This shifts the experience from optimizing isolated outputs to supporting longer running development efforts; where repositories are large, changes span multiple steps, and requirements aren’t always fully specified at the start.

What’s improved

• Model experiences 25% faster execution time, according to Open AI, than its predecessors so developers can accelerate development of new applications.
• Built for long-running tasks that involve research, tool use, and complex, multi‑step execution while maintaining context.
• Midtask steerability and frequent updates allow developers to redirect and collaborate with the model as it works without losing context.
• Stronger computer-use capabilities allow developers to execute across the full spectrum of technical work.

Common use cases

Developers and teams can apply GPT‑5.3‑Codex across a wide range of scenarios, including:

• Refactoring and modernizing large or legacy applications
• Performing multi‑step migrations or upgrades
• Running agentic developer workflows that span analysis, implementation, testing, and remediation
• Automating code reviews, test generation, and defect detection
• Supporting development in security‑sensitive or regulated environments

Pricing

GPT-Realtime-1.5 and GPT-Audio-1.5 at a glance

The models deliver measurable gains in reasoning and speech understanding for real‑time voice interactions on Microsoft Foundry. In OpenAI’s evaluations, it shows a +5% lift on Big Bench Audio (reasoning), a +10.23% improvement in alphanumeric transcription, and a +7% gain in instruction following, while maintaining low‑latency performance. Key improvements include:

What's improved

• More natural‑sounding speech: Audio output is smoother and more conversational, with improved pacing and prosody.
• Higher audio quality: Clearer, more consistent audio output across supported voices.
• Improved instruction following: Better alignment with developer‑provided system and user instructions during live interactions.
• Function calling support: Enables structured, tool‑driven interactions within real‑time audio flows.

Common use cases

Developers are using GPT-Realtime-1.5 and GPT-Audio-1.5 for scenarios where low‑latency voice interaction is essential, including:

• Conversational voice agents for customer support or internal help desks
• Voice‑enabled assistants embedded in applications or devices
• Live voice interfaces for kiosks, demos, and interactive experiences
• Hands‑free workflows where audio input and output replace keyboard interaction

Pricing

Getting started in Microsoft Foundry

Start building in Microsoft Foundry, evaluate performance, and explore Azure Open AI models today. Foundry brings evaluation, deployment, and governance into a single workflow, helping teams progress from experiments to scalable applications while maintaining security and operational controls.