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GPT-5.3

OpenAI · GPT-5

Deprecated GPT-5.3 Chat API route retained for historical and compatibility context.

Part of GPT family · Other versions: GPT-5.6 Luna , GPT-5.6 Terra , GPT-5.6 Sol , GPT-5.5 Pro , GPT-5.5 , GPT-Rosalind , GPT-5.4 mini , GPT-5.4 nano , GPT-5.4 Pro , GPT-5.4 , GPT-5.3-Codex , GPT-5.2-Codex , GPT-5.2 Pro , GPT-5.2 , GPT-5-Codex , GPT-5 mini , GPT-5 nano , GPT-5 , GPT-4.1 , GPT-4o mini Transcribe , GPT-4o mini TTS , GPT-4o Transcribe , Computer Use Preview , GPT-4o mini , GPT-4o
Type
language
Context
128K tokens
Max Output
16K tokens
Status
deprecated
Input
$1.75/1M tok
Output
$14/1M tok
API Access
Yes
License
proprietary
reasoning everyday-work agentic tool-use coding cost-efficient
Released March 2026 · Updated June 8, 2026

Overview

Freshness note: Model capabilities, limits, and pricing can change quickly. This profile is a point-in-time snapshot last verified on June 8, 2026.

This page is now best read as a deprecated GPT-5.3 Chat API entry. OpenAI launched GPT-5.3 Instant on March 3, 2026 as an everyday ChatGPT workhorse, but the current API model page for gpt-5.3-chat-latest marks the route deprecated. Keep existing integrations under review and route new API work to newer GPT-5.5 / GPT-5.4 models instead.

Capabilities

GPT-5.3 was designed for broad assistant work: drafting, coding, structured outputs, web-backed answers, and general professional workflows. Its historical value is as a ChatGPT-aligned conversational branch, not as a current recommended API target.

Technical Details

OpenAI’s current GPT-5.3 Chat model card lists a 128K context window, 16,384 max output tokens, and the model ID gpt-5.3-chat-latest. The route is explicitly deprecated, so treat those limits as compatibility information for older API users rather than planning targets.

Pricing & Access

Published API pricing for gpt-5.3-chat-latest (per 1M tokens):

  • Input: $1.75
  • Cached input: $0.175
  • Output: $14.00

OpenAI’s current API docs mark gpt-5.3-chat-latest as deprecated. Existing users should plan migration tests and avoid starting new systems on this route.

Best Use Cases

Use GPT-5.3 only for existing compatibility checks, regression comparisons, or historical model behavior analysis. It is not a sensible fresh-build target.

Comparisons

  • GPT-5.5 (OpenAI): Current fresh-build route for complex coding, reasoning, and agentic work.
  • GPT-5.4 (OpenAI): Newer non-deprecated GPT-5 branch for API workloads.
  • Claude Sonnet 4.6 (Anthropic): Strong alternative when you want a broad production model outside OpenAI’s stack.