OpenAI Launches GPT-5.5: First Fully Retrained Base Model Since GPT-4.5

30-Second Summary

OpenAI released GPT-5.5 on April 23, 2026, its first fully retrained base model since GPT-4.5. The model is designed to complete complex multi-step tasks with minimal human direction, operates across email, spreadsheets, calendars, and other applications, and matches GPT-5.4 latency while using significantly fewer tokens in Codex deployments.

At a Glance

• Topic: Model Releases
• Company: OpenAI
• Date: 23 April 2026
• What Changed: OpenAI released GPT-5.5 (codenamed Spud) to Plus, Pro, Business, and Enterprise users on April 23. It is the first fully retrained base model since GPT-4.5 and is designed for complex multi-step task execution with minimal human guidance. API pricing is $5/M input, $30/M output tokens with a 1M context window. GPT-5.5 Pro is available at $30/$180 per million tokens.
• Why It Matters: GPT-5.5 delivers a step change in autonomous task execution without increasing latency, and reduces per-task cost for enterprise Codex deployments through token efficiency. The model can operate across connected business applications independently, making it the most capable general-purpose agentic model available via API.
• Who Should Care: Operations managers and technical leads at companies using OpenAI via API or ChatGPT Enterprise who want to automate multi-step business processes with less human oversight.

Key Facts

• Company: OpenAI
• Date: 23 April 2026
• What Changed: OpenAI released GPT-5.5 (codenamed Spud) to Plus, Pro, Business, and Enterprise users on April 23. It is the first fully retrained base model since GPT-4.5 and is designed for complex multi-step task execution with minimal human guidance. API pricing is $5/M input, $30/M output tokens with a 1M context window. GPT-5.5 Pro is available at $30/$180 per million tokens.
• Who It Affects: Operations managers and technical leads at companies using OpenAI via API or ChatGPT Enterprise who want to automate multi-step business processes with less human oversight.
• Primary Source: OpenAI / CNBC / TechCrunch (https://openai.com/index/introducing-gpt-5-5/)

What Happened

OpenAI released GPT-5.5 (codenamed Spud) to Plus, Pro, Business, and Enterprise users on April 23. It is the first fully retrained base model since GPT-4.5 and is designed for complex multi-step task execution with minimal human guidance. API pricing is $5/M input, $30/M output tokens with a 1M context window. GPT-5.5 Pro is available at $30/$180 per million tokens.

Why It Matters

GPT-5.5 delivers a step change in autonomous task execution without increasing latency, and reduces per-task cost for enterprise Codex deployments through token efficiency. The model can operate across connected business applications independently, making it the most capable general-purpose agentic model available via API.

The David and Goliath View

This development reinforces our belief that the next generation of organisations will be built on intelligent systems, not larger teams. Operators running Codex or GPT-4.5-class agents should evaluate GPT-5.5 for the same workflows at lower token cost. Enterprise and Business subscribers have access now. API access is imminent.

Where This Fits in the AI Stack

AI Growth Engine: This development is relevant to revenue infrastructure. AI-driven prospecting, outreach automation, and pipeline management systems can leverage these capabilities to generate more pipeline with fewer resources. Employee Amplification Systems: This connects to employee amplification. Teams using AI copilots and workflow automation can apply these developments to multiply individual output without expanding headcount.

Questions Operators Are Asking

How does this affect my current AI strategy? Operators running Codex or GPT-4.5-class agents should evaluate GPT-5.5 for the same workflows at lower token cost. Enterprise and Business subscribers have access now. API access is imminent.

Should I act on this now? For organisations already deploying AI systems, this is worth incorporating into your next planning cycle. For those still evaluating, it adds context to the decision framework.

Citable Summary

• Title: OpenAI Launches GPT-5.5: First Fully Retrained Base Model Since GPT-4.5
• Publisher: David & Goliath Daily AI Briefing
• Date: 23 April 2026
• URL: https://davidandgoliath.ai/daily-ai-briefing/openai-launches-gpt-5-5-first-fully-retrained-base-model-since-gpt-4-5
• Source: OpenAI / CNBC / TechCrunch