OpenAI

GPT-5.5 Pro launched on April 24, 2026 as OpenAI’s highest-accuracy API tier, posting 93.6% on GPQA Diamond and 90.1% on BrowseComp. At $30 per million input tokens and $180 per million output tokens, it carries a 6x price premium over standard GPT-5.5 — a premium that is only defensible when accuracy failures carry measurable downstream cost. This guide covers the full pricing structure, reasoning.effort configuration, benchmark breakdown, competitive positioning against Claude Opus 4.7, enterprise compliance features, and cost optimization strategies to help engineering and architecture teams make a clear-eyed deployment decision. ...

GPT-6 is OpenAI’s next flagship model — pre-training completed on March 24, 2026 at the Stargate facility in Abilene, Texas, but the model has not shipped to the public as of May 2026. What’s confirmed, what’s projection, and what every developer building on the OpenAI API needs to know right now. What Is GPT-6? (And Why It’s Not What Most People Think) GPT-6 is OpenAI’s next-generation flagship language model, positioned as a significant architectural leap beyond GPT-5 and GPT-5.5. It is not simply an incremental update — OpenAI’s internal roadmap treats GPT-6 as the first model built from the ground up around long-term memory, multi-step agentic workflows, and a two-tier inference system that pairs fast System-1 responses with deliberate System-2 verification. Pre-training completed on March 24, 2026, using over 100,000 liquid-cooled H100 and B200 GPUs at the Stargate data center in Abilene, Texas — a $500B infrastructure bet funded by Microsoft, SoftBank, and Oracle. What most coverage gets wrong is conflating GPT-6 with GPT-5.5. The model known internally as “Spud” was widely expected to launch as GPT-6, but OpenAI shipped it as GPT-5.5 on April 23, 2026. GPT-6 is now the model beyond that — a distinction that matters for developers forecasting API migration timelines and capability planning through 2026. ...

OpenAI Agents SDK v2, released April 15, 2026, transforms the framework from a pure orchestrator into a full execution environment with configurable memory, sandboxed code execution, apply_patch filesystem tools, and support for 100+ LLMs — the most significant overhaul since the SDK replaced the experimental Swarm library in March 2025. What Is OpenAI Agents SDK v2? OpenAI Agents SDK v2 is the April 15, 2026 update to OpenAI’s open-source Python framework for building production-grade AI agents. The update — the largest since the SDK’s March 2025 launch — introduces a model-native harness that wraps the entire lifecycle of agent execution: memory management, tool access, sandbox orchestration, and filesystem operations. Unlike the v1 pure orchestrator design that left developers to wire up their own context, storage, and execution layers, v2 ships a turnkey harness that handles these concerns while remaining fully configurable. The SDK now supports over 100 non-OpenAI LLMs via the Chat Completions API, removing what had been the framework’s biggest criticism: vendor lock-in. With more than 4 million weekly users of OpenAI Codex as of 2026, the developer appetite for agentic tooling at this level is validated. The v2 harness covers five domains: configurable memory, filesystem tools (apply_patch and shell), sandbox execution across 7 providers, workspace manifests via AGENTS.md, and skills for progressive feature disclosure. ...

GPT-5.4 is OpenAI’s most capable general-purpose model as of 2026, combining a 1,050,000-token context window, native computer use at 75% OSWorld accuracy, and five tunable reasoning effort levels in a single Chat Completions API drop-in. Released March 5, 2026, it replaces gpt-5.2 for most production workloads with no endpoint change required. What Is GPT-5.4? Release Date, Model Variants, and What’s New GPT-5.4 is OpenAI’s flagship general-purpose language model released on March 5, 2026, and it represents the first mainline model to combine frontier reasoning, native computer control, and a 1-million-token context window in a single architecture. Unlike earlier specialized variants — o3 for reasoning or gpt-5.2 for general use — GPT-5.4 integrates GPT-5.3-codex coding capabilities directly, making it a unified backbone for agentic, analytical, and conversational workloads. On launch day, it scored 75.0% on the OSWorld-Verified computer use benchmark, surpassing the human expert baseline of 72.4% — a first for any general-purpose model. On knowledge work (GDPval), GPT-5.4 matches or outperforms industry professionals in 83% of comparisons across 44 occupations. There are two production variants: gpt-5.4 (the standard model, priced at $2.50/$15 per million input/output tokens) and gpt-5.4-pro (optimized for high-stakes enterprise tasks at $30/$180 per million input/output tokens). Both share the same API surface and context window; the pro variant allocates more compute budget per inference by default. ...

GPT-5.3 Codex Spark is OpenAI’s speed-first coding model, delivering over 1,000 tokens per second on Cerebras WSE-3 hardware — 15x faster than standard GPT-5.3 Codex, with a real-world task time of 50 seconds versus Codex’s 6 minutes. It trades reasoning depth for raw throughput. What Is GPT-5.3 Codex Spark? GPT-5.3 Codex Spark is OpenAI’s fastest coding model, purpose-built for low-latency, high-throughput developer workflows. Launched in February 2026 as a research preview for ChatGPT Pro subscribers, Spark runs on Cerebras WSE-3 wafer-scale hardware and delivers over 1,000 tokens per second — a 15x speed improvement over standard GPT-5.3 Codex. Unlike its sibling, which prioritizes deep reasoning across large codebases, Spark is optimized for tight feedback loops: quick edits, rapid prototyping, and iterative frontend development where speed matters more than multi-step architectural reasoning. It carries a 128k context window (versus Codex 5.3’s 192k), supports text-only input at launch, and integrates with the Codex CLI, VS Code extension, and the ChatGPT web interface. OpenAI reduced per-token overhead by 30% and time-to-first-token by 50% through WebSocket infrastructure improvements, making Spark feel genuinely interactive rather than asynchronous. For developers frustrated by the AI “thinking loop,” Spark’s throughput effectively eliminates the latency wall. ...

The OpenAI Agents SDK lets you build production-grade multi-agent pipelines in Python with fewer than 100 lines of core logic. Install it with pip install openai-agents, define agents with instructions and tools, connect them via handoffs or an orchestrator, and run with asyncio. This tutorial walks through a complete three-agent pipeline from setup to deployment. What Is the OpenAI Agents SDK and Why Does It Matter in 2026? The OpenAI Agents SDK is an open-source Python framework that provides four production-grade primitives — Agents, Handoffs, Guardrails, and Tracing — for building multi-step AI workflows without the boilerplate overhead of earlier frameworks. Released in early 2026 and reaching version 0.13.4 in April with full MCP server support, the SDK emerged as a response to a clear market need: 57% of organizations now deploy agents for multi-stage workflows, yet most teams were still stitching together ad-hoc pipelines using raw LLM calls and custom orchestration code. The SDK abstracts that complexity into composable primitives where each Agent is a configuration object wrapping an LLM with instructions, tool access, and optional output schemas. Handoffs allow agents to delegate work to peers; Guardrails validate inputs and outputs; Tracing captures every decision step for debugging and observability. The SDK is also model-agnostic — it supports any provider conforming to the chat completions API format, and integrates with 100+ LLMs via LiteLLM. For teams evaluating agentic frameworks in 2026, the SDK’s minimal surface area and tight OpenAI integration make it the fastest path from prototype to production. ...

Function calling is the bridge between a language model’s text output and the real world. Instead of asking a model to guess what the weather is, you hand it a get_weather tool definition, and it decides when to call it, what arguments to pass, and how to incorporate the result. As of 2026, every major provider—OpenAI, Anthropic, and Google—supports this pattern, but the APIs look meaningfully different. This guide walks through each one with working Python code and covers parallel calls, agent loops, security, and how to pick the right approach. ...

The OpenAI Computer Use API lets you build agents that see a screen, click, type, and navigate web browsers — all through a single API call. This guide walks you through every implementation option, from a 20-line quickstart to production-grade sandboxed agents. What Is the OpenAI Computer Use API? The OpenAI Computer Use API is a capability within the Responses API that lets the computer-use-preview model observe screenshots, interpret UI elements, and emit structured actions (click, type, scroll, keypress) to control a computer or browser. Unlike traditional automation libraries like Selenium or Playwright that require explicit CSS selectors or XPath queries, Computer Use reasons visually about any interface — it reads pixel-level screenshots and decides what to interact with next. OpenAI first released computer-use-preview in early 2026, following Anthropic’s lead with Claude’s computer use. As of April 2026, OpenAI’s API processes over 15 billion tokens per minute, and the computer use capability has become a foundation for autonomous QA testing, data extraction pipelines, and RPA replacement use cases. The model supports screenshots up to 10,240,000 pixels (using detail: "original"), with optimal resolutions of 1440×900 or 1600×900 for desktop environments. The core workflow is a loop: capture screenshot → send to model → receive action → execute action → repeat until task completes. ...

ChatGPT Workspace Agents are autonomous AI workers powered by Codex that your team builds once and runs continuously — reading files, calling APIs, posting to Slack, updating Salesforce, and completing multi-step workflows without hand-holding. Launched April 22, 2026, they replace custom GPTs for Business and Enterprise users. What Are ChatGPT Workspace Agents? (Powered by Codex) ChatGPT Workspace Agents are cloud-hosted autonomous AI workers that use OpenAI’s Codex model as their execution engine. Unlike chatbots that respond to a single prompt and stop, workspace agents can plan multi-step workflows, call connected tools (Slack, Google Workspace, Salesforce, Notion), write and run code, retain memory across sessions, and continue working in the background until a task is complete. Launched on April 22, 2026, they represent OpenAI’s clearest enterprise pivot to date: from conversational AI to operational AI. ...

GPT-5.5 Batch API and Flex mode both offer 50% off standard pricing — $2.50 per 1M input tokens and $15 per 1M output tokens versus the standard $5/$30 — giving high-volume AI coding teams a direct path to halving their monthly API spend without changing models or degrading output quality. What Is GPT-5.5 Batch API and Flex Mode? GPT-5.5 Batch API and Flex mode are two distinct pricing and execution tiers from OpenAI that both deliver 50% cost savings compared to standard API rates, but differ significantly in how and when results are returned. The Batch API is a fire-and-forget system: you submit up to 50,000 requests in a single JSONL file (up to 200MB), and OpenAI guarantees results within 24 hours. Flex mode, currently in beta as of April 2026, is interactive — requests are processed in real time but with variable latency ranging from a few seconds to several minutes, depending on platform load. GPT-5.5 launched on April 23, 2026, at standard pricing of $5 per 1M input tokens and $30 per 1M output tokens. Both Batch and Flex bring that cost down to $2.50/$15 — the same price as GPT-5.4 standard, but with GPT-5.5’s higher capability, including an 82.7% score on Terminal-Bench 2.0 and 58.6% on SWE-Bench Pro. For engineering teams running nightly code reviews, eval pipelines, or test generation jobs, the practical implication is straightforward: you get a better model at the same cost you were already paying. ...