GPT-5.5 Instant
- Family
- GPT-5.5
- Released
- 2026-05-05
- Context
- 400K
- Max output
- 128K
- Architecture
- Decoder Only
- Knowledge cutoff
- 2025-08
- Specialization
- general
- Openness
- Proprietary
- License
- ProprietaryRestricted
- Weights
- Not released
- Code
- Unknown
- Training
- Pretrained
Cheapest of 1 route · OpenAI API · cache read $0.500
About
GPT-5.5 Instant is OpenAI's latest Instant model used in ChatGPT, released May 5, 2026 as the new default ChatGPT model and exposed in the API as chat-latest. OpenAI says the update improves factuality, image analysis, STEM answers, web-search decisions, personalization from past chats/files/connected Gmail, and concise conversational style. OpenAI reports 52.5% fewer hallucinated claims than GPT-5.3 Instant on high-stakes prompts and 37.3% fewer inaccurate claims on difficult conversations flagged for factual errors.
Providers(1)
Compare API pricing across 1 tracked provider route for input and output tokens, batch, and cached reads when available.
| Provider | Input / 1M | Output / 1M | Cache | Route |
|---|---|---|---|---|
| OpenAI API | $5.00 | $30.00 | read $0.500 | Serverless |
Available via routers & gateways(15)
LiteLLM
GatewayOpen-source Python SDK and proxy server that unifies 100+ LLM APIs behind a single OpenAI-compatible interface, with load balancing, cost tracking, and configurable failover.
OpenRouter
HybridUnified hybrid gateway to 500+ models from 80+ providers via a single OpenAI-compatible API, with an optional Auto Router that selects a model per prompt from market spend data.
Portkey
GatewayProduction AI gateway routing to 1,600+ LLMs with failover, load balancing, caching, and guardrails; MIT-licensed open-source core is self-hostable. Now part of Palo Alto Networks as Prisma AIRS AI Gateway.
AIRouter
RouterCommercial LLM router (branded "AI Router" on its site) that picks the best model per request via a Decision API or an OpenAI-compatible Chat Completions endpoint, with a private selection mode that routes on anonymized patterns; sold as BYOK subscription plans priced by routed tokens.
Helicone
GatewayObservability-first AI gateway with routing, caching, rate limiting, and request tracing; Apache-2.0 open-source platform with a managed hosted tier for logging and analytics.
Kong AI Gateway
GatewayMulti-LLM AI gateway built on Kong Gateway 3.x, adding semantic routing, load balancing, guardrails, and MCP traffic analytics as plugins over Kong's existing API management platform.
Capabilities
Benchmark peer barsfor Coding
No task-mapped benchmark peers are available for this model yet.
Benchmark scores(4)
| Benchmark | Score | Version | Evaluation | Source |
|---|---|---|---|---|
| 76.0 | LLM-Stats aggregatorObserved 2026-06-07 | — | ||
| 1473.0 | text_style_control overall 2026-10-22 (style control, default view)Observed 2026-10-26 | Configuration: GPT-5.5 Instant Harness: LMArena blind pairwise human votes, Bradley-Terry Evaluator: LMArena Confidence: confirmed Notes: LMArena text style control leaderboard, overall category, published 2026-10-22 (HF lmarena-ai/leaderboard-dataset @9761a3ce, latest split). Board entry 'GPT-5.5 Instant': rank 43, Arena Score 1473.2 (95% CI 1468.2-1478.2), 27163 votes. Retrieved 2026-10-26. | Source Source: LMArena (lmarena.ai), CC BY 4.0 | |
| 1276.0 | vision_style_control overall 2026-10-19 (style control, default view)Observed 2026-10-26 | Configuration: GPT-5.5 Instant Harness: LMArena blind pairwise human votes, Bradley-Terry Evaluator: LMArena Confidence: confirmed Notes: LMArena vision style control leaderboard, overall category, published 2026-10-19 (HF lmarena-ai/leaderboard-dataset @9761a3ce, latest split). Board entry 'GPT-5.5 Instant': rank 33, Arena Score 1276.1 (95% CI 1267.3-1284.8), 7590 votes. Retrieved 2026-10-26. | Source Source: LMArena (lmarena.ai), CC BY 4.0 | |
| 1418.0 | text creative_writing 2026-10-22Observed 2026-10-22 | Configuration: GPT-5.5 Instant Harness: LMArena blind pairwise human votes, Bradley-Terry Evaluator: LMArena Confidence: confirmed Notes: LMArena Text arena, Creative Writing category (no style control), board published 2026-10-22 (HF lmarena-ai/leaderboard-dataset @a467e6b9, text config, latest split). Board entry 'GPT-5.5 Instant' (category creative_writing in text/latest-00000-of-00001.parquet): rank 70 of 416, rating 1418.2 (95% CI 1408.6-1427.8), 4357 votes. Source: LMArena (CC BY 4.0). Retrieved 2026-10-27. | Source Source: LMArena (lmarena.ai), CC BY 4.0 |
Migration checks
No linked migration route is available for this model yet.
API versions
chat-latestCompare GPT-5.5 Instant with other models
- GPT-5.5 Instant vs GPT-5.3-Codex592
- GPT-5.5 Instant vs Kimi K2.6538
- GPT-5.5 Instant vs o3 Deep Research212
- GPT-5.5 Instant vs Gemini 2.5 Flash Live API135
- GPT-5.5 Instant vs Gemini 3.1 Flash TTS Preview104
- GPT-5.5 Instant vs Qwen3.6 Max Preview82
- GPT-5.5 Instant vs Claude Mythos Preview70
- GPT-5.5 Instant vs Mistral Large 2 (2407)59
Comparison and alternatives
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Cheapest of 1 route · OpenAI API · cache read $0.500