This is it. One day before Claude 4 Opus and Claude 4 Sonnet shut down permanently. If you haven't started your migration yet, you're cutting it close — but you can still finish in time. This guide gives you the fastest path off Claude 4 with the least risk.
The 30-Minute Migration Checklist
Here's exactly what to do, in order. Most developers finish this in 15-30 minutes:
- ☐ Step 1: Search your codebase for
claude-4-opusandclaude-4-sonnet - ☐ Step 2: Replace model IDs with
claude-opus-4-8orclaude-sonnet-4-6 - ☐ Step 3: Test with 5-10 API calls in development
- ☐ Step 4: Deploy to staging and run your test suite
- ☐ Step 5: Deploy to production
- ☐ Step 6: Calculate your new costs with APIpulse
Find Every Claude 4 Reference
Run this in your project root:
grep -r "claude-4-opus\|claude-4-sonnet" --include="*.js" --include="*.ts" --include="*.py" --include="*.json" .This finds every file that references the deprecated model IDs. Don't forget config files, environment variables, and documentation.
Update Model IDs
The API format is identical — you only change the model name:
// Before (deprecated — will fail June 15)
model: "claude-4-opus"
// After (official successor)
model: "claude-opus-4-8"No other code changes needed. Same API, same SDK, same parameters.
Test and Deploy
Make a few test calls to verify the new model works with your prompts. Then deploy. That's it — you're migrated.
Cost Comparison: Claude 4 vs Alternatives
Here's what you're paying now vs what you could pay after migration (per 1M tokens):
Budget Alternatives (if you want to save even more)
Calculate Your Exact Savings
Enter your monthly token usage and see exactly how much you'll save by migrating off Claude 4.
What If You're Using Claude 4 Through a Third Party?
If you access Claude 4 via OpenRouter, Amazon Bedrock, or another provider, you still need to update your model ID. Some providers may have already removed Claude 4 from their available models list. Check your provider's dashboard for the latest status.
LangChain and LlamaIndex Users
Update your model string in the chat instantiation:
# LangChain
chat = ChatAnthropic(model="claude-opus-4-8") # was "claude-4-opus"
# LlamaIndex
llm = Anthropic(model="claude-opus-4-8") # was "claude-4-opus"Both libraries use the same underlying SDK — only the model ID changes.
Why Migrate to Claude Opus 4.8?
Claude Opus 4.8 is the official successor to Claude 4 Opus. It offers:
- 67% lower cost — $5/$25 vs $15/$75 per 1M tokens
- Same API format — zero code changes beyond the model ID
- Better performance — improved reasoning, longer context
- No deprecation risk — this is the current flagship model
Don't Wait Until June 15
Use the APIpulse cost calculator to see exactly how much you'll save, then migrate today. It takes 30 minutes — your app will be cheaper and more reliable.
Calculate Your Savings →Frequently Asked Questions
Can I get an extension on the Claude 4 deadline?
No. Anthropic has confirmed there is no grace period, no extension, and no degraded mode. The shutdown is hard: June 15, 2026.
What if I miss the deadline?
Your API calls will fail immediately with a 404 error. You'll need to update your model ID and redeploy. There's no way to keep using Claude 4 after June 15.
Will my prompts work the same on Claude Opus 4.8?
Yes. Claude Opus 4.8 uses the same API format and responds to the same prompts. You may see slightly different outputs (it's a newer model), but your existing prompts will work without modification.
What if I have fine-tuned Claude 4 models?
Fine-tuned models will also stop working. You'll need to re-fine-tune on Claude Opus 4.8 or Claude Sonnet 4.6. Contact Anthropic support for guidance on transferring fine-tuned weights.
Is it worth switching to a cheaper provider like DeepSeek?
It depends on your quality requirements. DeepSeek V4 Pro is 97% cheaper and handles most tasks well, but Claude Opus 4.8 may be better for complex reasoning. Use the APIpulse comparison tool to test both against your use case.
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