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ease
features
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Description

GPT-5.3-Codex-Spark is OpenAI’s first model purpose-built for real-time coding within the Codex ecosystem. Engineered for ultra-low latency, it can generate more than 1000 tokens per second when running on Cerebras’ Wafer Scale Engine hardware. Unlike larger frontier models designed for long-running autonomous tasks, Codex-Spark specializes in rapid iteration, targeted edits, and immediate feedback loops. Developers can interrupt, redirect, and refine outputs interactively, making it ideal for collaborative coding sessions. The model features a 128k context window and is currently text-only during its research preview phase. End-to-end latency improvements—including WebSocket streaming and inference stack optimizations—reduce time-to-first-token by 50% and overall roundtrip overhead by up to 80%. Codex-Spark performs strongly on benchmarks such as SWE-Bench Pro and Terminal-Bench 2.0 while completing tasks significantly faster than its larger counterpart. It is available to ChatGPT Pro users in the Codex app, CLI, and VS Code extension with separate rate limits during preview. The model maintains OpenAI’s standard safety training and evaluation protocols. Codex-Spark represents the beginning of a dual-mode Codex future that blends real-time interaction with long-horizon reasoning capabilities.

Description

fx is a compact, open-source coding agent and command-line interface (CLI) developed in Zig, specifically optimized for research applications, performance, and seamless integration into larger systems. Its architecture emphasizes minimalism throughout the system prompt, available tools, feature set, memory usage, and maintains a small binary size of just 6 MB, aiming for an interface experience that resembles a Unix shell rather than a cumbersome terminal IDE. With an impressive cold start time in microseconds, fx avoids unnecessary tasks or input/output operations before receiving commands, making it ideal for programmatic applications, environments with limited resources, and agent sandboxes. Developers can easily initiate it within a project to perform tasks such as reading files, searching through code, executing commands, implementing changes, running tests, and streaming tool activations in real time. The underlying framework is both model- and provider-independent, enabling compatibility with local models, API gateways, direct provider connections, and cloud-based inference options. By design, it maximizes context efficiency, utilizing a succinct system prompt and streamlined toolset to minimize token overhead and enhance the speed of response to the first token generated. In addition, this unique focus on lightweight operation and quick interaction allows developers to maintain productivity without the typical overhead associated with more complex environments.

API Access

Has API Yes 

API Access

Has API No 

Screenshots View All

Screenshots View All

Integrations

Codex CLI Yes 
Codex Security Yes 
Microsoft Foundry Yes 
OpenAI Yes 
OpenAI Codex Yes 
OpenClaw Yes 

Integrations

Codex CLI No 
Codex Security No 
Microsoft Foundry No 
OpenAI No 
OpenAI Codex No 
OpenClaw No 

Pricing Details

No price information available.
Free Trial No 
Free Version No 

Pricing Details

Free
Free Trial No 
Free Version Yes 

Deployment

Web-Based Yes 
On-Premises No 
iPhone App No 
iPad App No 
Android App No 
Windows No 
Mac No 
Linux No 
Chromebook No 

Deployment

Web-Based Yes 
On-Premises No 
iPhone App No 
iPad App No 
Android App No 
Windows No 
Mac No 
Linux No 
Chromebook No 

Customer Support

Business Hours No 
Live Rep (24/7) No 
Online Support Yes 

Customer Support

Business Hours No 
Live Rep (24/7) No 
Online Support Yes 

Types of Training

Training Docs Yes 
Webinars No 
Live Training (Online) No 
In Person No 

Types of Training

Training Docs Yes 
Webinars No 
Live Training (Online) No 
In Person No 

Vendor Details

Company Name

OpenAI

Founded

2015

Country

United States

Website

openai.com

Vendor Details

Company Name

Vercel

Founded

2015

Country

United States

Website

fx.sh/

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