WhichAI / Models / GPT-5.5

GPT-5.5

· verified October 14, 2026

public free paid api in Generator coding reasoning writing

Provider

Statuspublic

AA Intelligence Index38.4 (official, read October 14, 2026)

Released2026-04

Context window1.05M

Modalitiesn/a

API price $/1M (in / out)$5 / $30 (OpenRouter)

Speedn/a

AccessFree (limited messages) · Plus $20/mo · Go ~$8/mo · API

In one line

The April 2026 flagship, still the strongest broad generalist most people can use free: brainstorming, drafting, frontier coding (SWE-bench Verified 88.7%).

Coding88

Reasoning86

Writing82

Agents & tools84

Category scores (0-100) are WhichAI blended ratings: public category leaderboards plus editorial judgment. Guidance, not official measurements.

Alternatives worth a look

Claude Sonnet 5 (Anthropic) · AA 38.2FREE tier of claude.ai · API
GPT-6 Luna (OpenAI) · AA 38.1API $0.1/$0.5 per 1M tokens on OpenRouter · listed September 22, 2026
Grok 4.5 (xAI) · AA 38.8Released July 8, 2026 · API $2/$6 per 1M tokens · in Grok Build & Cursor · not yet in the EU

Head-to-head: GPT-5.5 vs Claude Sonnet 5 · GPT-5.5 vs Claude Opus 4.8

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Artificial Analysis Intelligence Index, official scale (the number published on artificialanalysis.ai), relayed by OpenRouter and refreshed automatically: last read October 14, 2026. 209 models carry a current official measurement. A value marked ~ is converted from an earlier snapshot because no current measurement is published; an unmeasured model is never ranked. Context, price, modality and listing dates come from the public OpenRouter model list (refreshed automatically on the live site; static copy retrieved October 3, 2026) and vendor pages. Missing values are not published or not yet verified - shown as -. Sources are linked inside the app (the Ranking chapter and About > Methodology).