What Is Claude Code Fast Mode?
Claude Code fast mode is a new performance option that delivers faster Opus 4.6 responses directly inside your terminal or VS Code editor. Instead of waiting for standard response times, fast mode uses a different API configuration that prioritizes speed — giving you near-instant feedback while coding, debugging, or iterating on projects.
To enable it, simply type /fast in Claude Code's CLI or VS Code Extension. You'll see a ↯ (lightning bolt) icon confirming fast mode is active. It's not a different model — you're still getting the same Claude Opus 4.6 intelligence, just with an API configuration optimized for lower latency. The tradeoff is higher per-token cost, which we'll break down below.
Fast mode is available on Pro, Max, Team, and Enterprise subscription plans, as well as through the Anthropic Console. It uses extra usage credits only — it's not included in your standard subscription rate limits. And right now, there's a 50% introductory discount running until February 16, 2026 at 11:59 PM PT, making it an excellent time to try it out.
For developers who spend hours in Claude Code daily, fast mode can meaningfully reduce wait times during rapid iteration and live debugging sessions. Here at Serenities AI, we've been testing it extensively and found it particularly valuable for time-sensitive development work.
How to Enable Fast Mode in Claude Code
Activating fast mode takes seconds. Here's how to do it in both environments:
In the CLI (Terminal)
- Open Claude Code in your terminal
- Type
/fastand press Enter - Look for the ↯ icon in your prompt — this confirms fast mode is active
- To switch back, type
/fastagain to toggle it off
In VS Code Extension
- Open the Claude Code panel in VS Code
- Type
/fastin the input field - The ↯ indicator will appear when fast mode is enabled
- Toggle off the same way
One important detail: fast mode persists across sessions. Once you enable it, it stays on until you explicitly turn it off. You won't need to re-enable it every time you start a new Claude Code session.
Fast Mode Pricing Breakdown
Fast mode costs more per token than standard mode because it uses a prioritized API path. Here's the full pricing breakdown:
| Context Window | Input Cost (per MTok) | Output Cost (per MTok) |
|---|---|---|
| Under 200K tokens | $30 | $150 |
| Over 200K tokens | $60 | $225 |
50% Introductory Discount
Anthropic is currently offering a 50% discount on all fast mode usage until February 16, 2026 at 11:59 PM PT. That means you're effectively paying:
| Context Window | Discounted Input | Discounted Output |
|---|---|---|
| Under 200K tokens | $15/MTok | $75/MTok |
| Over 200K tokens | $30/MTok | $112.50/MTok |
This discount makes fast mode surprisingly affordable for short coding sessions where context stays under 200K tokens. If you've been curious about trying it, now is the time.
Important: Extra Usage Only
Fast mode is billed as extra usage — it does not count against your subscription's included rate limits. This means your normal Claude Code usage remains unaffected. Fast mode is purely additive: you pay for the speed boost on top of your existing plan.
When to Use Fast Mode vs. Standard Mode
Fast mode isn't always the right choice. Here's a practical comparison to help you decide:
| Scenario | Best Mode | Why |
|---|---|---|
| Rapid iteration | Fast ↯ | Quick back-and-forth saves minutes per session |
| Live debugging | Fast ↯ | Faster feedback loop when hunting bugs |
| Time-sensitive work | Fast ↯ | Deadlines don't wait for model latency |
| Long autonomous tasks | Standard | No need to pay premium when you're not waiting |
| Batch processing | Standard | Cost efficiency matters more than speed |
| Cost-sensitive workloads | Standard | Standard mode is significantly cheaper per token |
Pro Tip: Combine Fast Mode with Lower Effort Levels
Here's a power-user trick that many developers miss: you can combine fast mode with a lower effort level for maximum speed. Claude Code's effort setting controls how thoroughly the model reasons before responding. By dropping the effort level while keeping fast mode on, you get the absolute fastest responses possible — ideal for quick questions, simple code generation, or when you just need a fast answer.
This combination is particularly effective for tasks like:
- Generating boilerplate code
- Quick syntax checks
- Simple refactoring suggestions
- Documentation generation
For deeper reasoning tasks like complex architecture decisions or multi-file refactors, you'll want to keep the effort level higher even with fast mode enabled. Check out our Claude Code tips and tricks guide for more power-user techniques.
Availability and Platform Support
Fast mode is available across most Claude Code access methods, but not all:
| Platform | Fast Mode Available? |
|---|---|
| Claude Code CLI | ✅ Yes |
| VS Code Extension | ✅ Yes |
| Anthropic Console | ✅ Yes |
| Pro / Max plans | ✅ Yes |
| Team / Enterprise | ✅ Yes (admin must enable) |
| AWS Bedrock | ❌ Not available |
| Google Vertex AI | ❌ Not available |
| Azure Foundry | ❌ Not available |
Team and Enterprise Setup
If you're on a Team or Enterprise plan, there's an extra step: an admin must enable fast mode before individual team members can use it. Fast mode is disabled by default on these plans for cost control purposes. Once an admin enables it, all team members can toggle it with the /fast command.
Understanding the Technical Details
A common misconception is that fast mode uses a different, smaller model. That's not the case. Fast mode runs the exact same Claude Opus 4.6 model — the difference is entirely in the API configuration. Anthropic prioritizes your requests in their infrastructure, reducing queue times and optimizing for lower latency at the cost of higher per-token pricing.
This means you get:
- Same intelligence — identical model capabilities, knowledge, and reasoning
- Same context window — full Opus 4.6 context length
- Same tool use — all Claude Code features work identically
- Faster response times — reduced latency for both first-token and overall completion
The ↯ icon in your prompt serves as a constant visual reminder that you're in fast mode and incurring the higher per-token rate.
Cost Management Tips
Since fast mode uses extra usage billing, here are some practical strategies to keep costs under control:
- Toggle strategically — Enable fast mode only during active coding sessions where you're waiting on responses. Turn it off when kicking off long-running tasks.
- Keep context short — Under 200K tokens, fast mode costs $30/$150 per MTok. Over 200K, it jumps to $60/$225. Start fresh sessions for new tasks.
- Use the discount window — The 50% discount runs until February 16, 2026. Take advantage of it to experiment without committing to full price.
- Combine with effort levels — Lower effort + fast mode = cheapest fast option for simple tasks.
- Monitor your usage — Check your Anthropic dashboard regularly to track fast mode spending separately.
Frequently Asked Questions
Is Claude Code fast mode a different AI model?
No. Fast mode uses the exact same Claude Opus 4.6 model. The difference is in the API configuration — Anthropic prioritizes your requests for lower latency, which is why it costs more per token. You get identical intelligence, reasoning, and capabilities.
How much does fast mode cost compared to standard mode?
Fast mode costs $30/$150 per million tokens (input/output) under 200K context, and $60/$225 over 200K context. There's currently a 50% introductory discount running until February 16, 2026. All fast mode usage is billed as extra usage on top of your subscription.
Can I use fast mode on AWS Bedrock or Google Vertex AI?
No. Fast mode is currently only available through Anthropic's direct platform — the Claude Code CLI, VS Code Extension, and Anthropic Console. It is not available on AWS Bedrock, Google Vertex AI, or Azure Foundry.
Does fast mode reset when I close Claude Code?
No. Fast mode persists across sessions. Once you toggle it on with /fast, it stays enabled until you explicitly toggle it off. The ↯ icon will appear in your prompt whenever fast mode is active.
Do I need a specific subscription plan to use fast mode?
Fast mode is available on Pro, Max, Team, and Enterprise plans, as well as through the Anthropic Console. For Team and Enterprise plans, an administrator must enable fast mode first — it's disabled by default. All fast mode usage is billed as extra usage outside your normal subscription limits.