GPT-5.5 Instant
GPT-5.5 Instant is worth evaluating for coding, rag, and agents when its provider route and context window match the workload.
Use it for
- Teams evaluating coding, rag, and agents
- Workloads that can use a 400k context window
- Buyers comparing 1 tracked provider route
Do not use it for
- Workloads where another current model has stronger sourced task evidence
- Family
- GPT-5.5
- Released
- 2026-05-05
- Context
- 400k
- Max output
- 128,000
- Architecture
- Decoder Only
- Knowledge cutoff
- 2025-08
- Specialization
- general
- Openness
- Proprietary
- License
- ProprietaryCommercial use: conditional
- 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.
GPT-5.5 Instant is a proprietary model in the GPT-5.5 family. The structured metadata tracks a 400k-token context window, multimodal input, function calling, tool use, structured outputs, and code execution. This page tracks provider routes through OpenAI API, with the cheapest tracked route listed at $5 input and $30 output per 1M tokens. Headline tracked benchmarks include MMMU Pro 76.0.
Top use-case fit: coding, agents, and build tasks
Coding
Included by capability and metadata signals in the decision map.
RAG
Included by capability and metadata signals in the decision map.
Agents
Included by capability and metadata signals in the decision map.
Provider price ladder
Compare API pricing across 1 providers 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 400+ models from 60+ providers via a single OpenAI-compatible API, with optional auto-routing that selects the best model per prompt.
Portkey
GatewayProduction AI gateway routing to 1,600+ LLMs with failover, load balancing, semantic caching, and guardrails; Apache 2.0 core is fully self-hostable with the complete feature set.
AIRouter
RouterCommercial LLM router that analyzes incoming requests and routes to the optimal model for cost/quality/latency via a drop-in OpenAI-compatible API, with a privacy-preserving embedding mode that avoids sending prompt content.
Helicone
GatewayObservability-first AI gateway with routing, caching, rate limiting, and request tracing; Apache 2.0 open-source core 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(1)
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 259
Comparison and alternatives
Browse all comparisons →Show all 21 popular comparisonssorted by 7-day search impressions
Frequently asked questions
What is the context window of GPT-5.5 Instant?
GPT-5.5 Instant has a context window of 400k tokens.
What is the max output of GPT-5.5 Instant?
GPT-5.5 Instant can generate up to 128,000 output tokens.
How much does GPT-5.5 Instant cost?
GPT-5.5 Instant is available at $5.00/1M input tokens through OpenAI API.
When was GPT-5.5 Instant released?
GPT-5.5 Instant was released on 2026-05-05.
Which providers offer GPT-5.5 Instant?
GPT-5.5 Instant is available from 1 provider: OpenAI API.
What benchmarks has GPT-5.5 Instant been tested on?
GPT-5.5 Instant has been evaluated on 1 benchmark, including MMMU Pro.
Cheapest of 1 route · OpenAI API · cache read $0.500