ChatGPT vs Claude vs Gemini vs Grok

OpenAI's ChatGPT remains the most widely-used AI assistant in the world. GPT-5.5 (April 23, 2026) takes #1 on the Artificial Analysis Intelligence Index with a score of 60, three points ahead of Claude Opus 4.7 and Gemini 3.1 Pro at 57. It dominates shell automation (Terminal-Bench 2.0: 82.7%, +13 over Opus 4.7) and advanced math (FrontierMath Tier 4: 35.4%). API pricing doubled vs 5.4 to $5/$30 per million tokens; a new GPT-5.5 Pro variant for longer reasoning sits at $30/$180. Codex now has a 1M-token context window with optional fast-mode at 2.5x cost. Honest caveats: GPT-5.5 still loses SWE-Bench Pro to Claude Opus 4.7 (58.6% vs 64.3%), loses MCP Atlas tool-use to both Opus (79.1%) and Gemini (78.2%), and posts an 86% hallucination rate on AA-Omniscience. The ecosystem advantage remains unmatched: DALL-E, Codex, Atlas browser, 60+ connectors, Memory, Projects, GPT Store, and Microsoft 365 Copilot integration. Sora video app/API is being discontinued (web/app April 26, 2026; API September 24, 2026).

Anthropic's Claude Opus 4.7 (April 16, 2026) still leads production coding with 87.6% on SWE-bench Verified and 64.3% on SWE-bench Pro, beating GPT-5.5 (58.6%) and Gemini 3.1 Pro despite GPT-5.5's broader Intelligence Index lead. Anthropic also wins MCP Atlas tool-use at 79.1%. Anthropic surpassed OpenAI in enterprise revenue in 2026 ($30B vs $25B annualized). The ecosystem expanded dramatically in April 2026: Claude Design (Anthropic Labs, April 17) for visual work tied to your codebase, Claude Code Routines (April 16) for cloud-hosted automation with schedule/webhook/GitHub triggers, a full desktop redesign (April 14) with parallel agent sessions and git worktree isolation, Claude Cowork GA on macOS and Windows, Agent Skills as an open standard with 1,000+ ready-made skills, and Computer Use in research preview. The 1M-token context window is now at standard API pricing with no long-context premium.

Google's Gemini 3.1 Pro (February 2026) remains the flagship and leads on abstract reasoning (ARC-AGI-2: 77.1%) and graduate-level science (GPQA Diamond: 94.3%). Native multimodal across text, image, audio, and video with 1M-token context and 7x cheaper API pricing than Opus 4.7. The April 2026 addition of Gemini 3.1 Flash TTS brings 70+ languages and audio tags for inline voice direction. Deep integration across Google Workspace, NotebookLM in-app, and Veo 3.1 for video generation make this the most flexible multimodal stack.

xAI's Grok 4.20 (March 2026) ships in three variants: standard reasoning, non-reasoning, and a dedicated multi-agent version where Grok coordinates with Harper (research), Benjamin (logic/math), and Lucas (contrarian) running in parallel. Grok 4 Heavy was the first model to break 50% on Humanity's Last Exam (50.7%), and Grok 4.20 holds an industry-lowest 22% hallucination rate on the AA-Omniscience benchmark (beating Claude 4.5 Haiku, MiniMax V2 Pro, and GLM-5). xAI merged with SpaceX in February 2026 (combined valuation $1.25T) to pursue orbital data centers. The lineup includes grok-4.20-0309 (flagship, $2/$6 per M), grok-4.20-multi-agent-0309 (multi-agent version), grok-4-1-fast (2M context, $0.20/$0.50 per M tokens), grok-code-fast-1 for agentic coding, and Grok Imagine for image + video. Grok 5 is in training on Colossus 2, expected Q2/Q3 2026.