Which AI writes better code?
It's the question every developer asks before committing to a $20/month subscription — or building their entire workflow around an API. ChatGPT with GPT-4 has the mindshare. Claude has the developer buzz. Both claim to be the best coding assistant.
I've spent months using both for real software development work. Building features, debugging production issues, reviewing pull requests, architecting systems. Here's what I actually found.
Spoiler: One of them has a clear edge for serious development work. But the answer depends on how you code.
TL;DR — The Developer's Verdict
For code generation: Claude wins. Cleaner code, better patterns, fewer hallucinations.
For debugging: Claude wins. More thorough analysis, catches subtle issues.
For code review: Claude wins. Understands context, not just syntax.
For quick completions: GPT-4 wins. Faster, more concise for small tasks.
For long codebases: Claude wins. 200K+ tokens vs 128K.
For ecosystem/tools: GPT-4 wins. Code Interpreter, plugins, broader IDE support.
My pick: Claude for serious development. GPT-4 for quick tasks and when you need the ecosystem.
Quick Comparison: Claude vs GPT-4 for Coding (2026)
| Feature | Claude (Sonnet 4.5) | GPT-4o / GPT-4 |
|---|---|---|
| Context Window | ⭐ 200K tokens | 128K tokens |
| Code Quality | ⭐ Excellent | Very Good |
| Debugging | ⭐ Thorough | Good |
| Follows Instructions | ⭐ Excellent | Good (sometimes drifts) |
| Speed | Fast | ⭐ Very Fast |
| Code Execution | Artifacts (preview) | ⭐ Code Interpreter |
| API Input Price | $3/M tokens (Sonnet) | $2.50/M tokens (4o) |
| API Output Price | $15/M tokens | $10/M tokens |
| IDE Integrations | Cursor, Continue, Claude Code | ⭐ Copilot, Cursor, many more |
| Agentic Coding | ⭐ Claude Code | Limited |
1. Code Generation Quality: The Real Comparison
This is what matters most. When you describe a feature and ask for code, what do you get?
Test: Build a Rate Limiter
I asked both to implement a sliding window rate limiter in Python.
Claude's output:
import time
from collections import defaultdict
from threading import Lock
from typing import Optional
class SlidingWindowRateLimiter:
"""
Token bucket rate limiter with sliding window.
Thread-safe implementation for production use.
"""
def __init__(
self,
requests_per_window: int,
window_seconds: float = 60.0
):
self.requests_per_window = requests_per_window
self.window_seconds = window_seconds
self.requests: dict[str, list[float]] = defaultdict(list)
self._lock = Lock()
def is_allowed(self, client_id: str) -> bool:
"""Check if request is allowed and record it if so."""
now = time.monotonic()
window_start = now - self.window_seconds
with self._lock:
# Clean old requests outside the window
self.requests[client_id] = [
ts for ts in self.requests[client_id]
if ts > window_start
]
if len(self.requests[client_id]) < self.requests_per_window:
self.requests[client_id].append(now)
return True
return False
def get_retry_after(self, client_id: str) -> Optional[float]:
"""Return seconds until next request is allowed, or None if allowed now."""
now = time.monotonic()
window_start = now - self.window_seconds
with self._lock:
timestamps = [
ts for ts in self.requests[client_id]
if ts > window_start
]
if len(timestamps) < self.requests_per_window:
return None
oldest = min(timestamps)
return max(0.0, oldest + self.window_seconds - now)
GPT-4's output:
import time
from collections import defaultdict
class RateLimiter:
def __init__(self, max_requests, window_size):
self.max_requests = max_requests
self.window_size = window_size
self.requests = defaultdict(list)
def is_allowed(self, client_id):
current_time = time.time()
# Remove old requests
self.requests[client_id] = [
req for req in self.requests[client_id]
if current_time - req < self.window_size
]
if len(self.requests[client_id]) < self.max_requests:
self.requests[client_id].append(current_time)
return True
return False
What's Different?
| Aspect | Claude | GPT-4 |
|---|---|---|
| Thread safety | ✅ Included with Lock | ❌ Missing |
| Type hints | ✅ Full annotations | ❌ None |
| Docstrings | ✅ Clear, useful | ❌ None |
| Helper methods | ✅ get_retry_after() | ❌ None |
| time.monotonic() | ✅ Correct for intervals | ❌ Uses time.time() (can drift) |
| Production-ready | ✅ Yes | ⚠️ Needs work |
Claude's code is production-ready. GPT-4's code works but needs iteration to be safe for real use.
This pattern repeats across dozens of tests. Claude generates code that senior developers would write. GPT-4 generates code that works but often needs a second pass for edge cases, thread safety, and type annotations.
Why This Happens
Claude's training emphasizes following specifications precisely and anticipating requirements. When you ask for a rate limiter, Claude considers: Will this run in a multi-threaded environment? Should there be a way to check retry timing? What about type hints for IDE support?
GPT-4 answers the literal question. You asked for a rate limiter, you got a rate limiter. It works. But you'll be back in 10 minutes asking about thread safety.
Winner: Claude — by a meaningful margin for production code.
For a head-to-head comparison of the dedicated coding assistants built on these models, see our Cursor vs GitHub Copilot guide.
2. Debugging: Finding the Bug That Shouldn't Exist
Both AIs can spot syntax errors and obvious bugs. The real test is subtle, logic-level issues.
Test: The Sneaky Off-by-One
I gave both this function with a non-obvious bug:
def get_page_items(items: list, page: int, per_page: int = 10) -> list:
"""Return items for the given page number (1-indexed)."""
start = (page - 1) * per_page
end = start + per_page
return items[start:end] if start < len(items) else []
The bug: When page is 0 or negative, start becomes negative, and Python's slice behavior returns unexpected results instead of an empty list.
Claude's response:
"There's a boundary issue. When
pageis 0 or negative,startbecomes negative. Python's slicing with negative indices counts from the end, soitems[-10:0]returns an empty list (which happens to be correct), butitems[-10:]would return the last 10 items if someone passes page=0 with adjusted logic.More critically, there's no validation. I'd add:
if page < 1: return []Also consider: what if
per_pageis 0 or negative? That creates an infinite loop potential in pagination logic."
GPT-4's response:
"The function looks correct. It handles the case where the start index exceeds the list length by returning an empty list. The slicing is standard Python behavior."
GPT-4 missed the bug entirely. Claude not only found it but identified a second potential issue I hadn't considered.
Why Claude is Better at Debugging
Claude approaches debugging like a code reviewer, not a compiler. It asks:
- What could a caller pass that breaks this?
- What assumptions are implicit?
- What happens at the boundaries?
GPT-4 tends to validate that the code "works" for the happy path, which isn't the same as finding bugs.
Winner: Claude — substantially better at catching subtle issues.
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3. Code Review: Beyond Syntax Checking
Code review isn't just about finding bugs. It's about maintainability, patterns, and whether the code makes sense in context.
Test: Review This Pull Request
I gave both a PR that added a caching layer:
# New caching implementation
cache = {}
def get_user(user_id):
if user_id in cache:
return cache[user_id]
user = db.fetch_user(user_id)
cache[user_id] = user
return user
def invalidate_user(user_id):
if user_id in cache:
del cache[user_id]
Claude's review:
Issues identified:
Memory leak risk — Global cache grows unbounded. Production systems need TTL or LRU eviction.
Thread safety — If this runs in a web server (likely, given user fetching), concurrent access to
cachedict is unsafe in some Python implementations.Cache stampede — Multiple simultaneous requests for the same uncached user will all hit the database. Consider locking or request coalescing.
No cache metrics — You'll want to track hit/miss rates. Add logging or a metrics counter.
Testing concern — Global cache makes unit testing harder. Consider dependency injection.
Suggestion: Use
functools.lru_cachefor simple cases, orcachetools.TTLCachefor production. If you need distributed caching, Redis is the standard choice.
GPT-4's review:
"The code implements a basic caching mechanism. It correctly checks if the user is in the cache before fetching from the database. The invalidate function properly removes entries.
Consider adding type hints for better code documentation."
The Difference is Depth
Claude reviews like a senior engineer who's seen production failures. GPT-4 reviews like someone checking if the code compiles.
For real code review, you need an AI that understands consequences, not just correctness. Claude does this. GPT-4 mostly doesn't.
Winner: Claude — significantly more useful for actual code review.
4. Context Window: Why 200K Tokens Matters for Developers
| Model | Context Window | Approximate Lines of Code |
|---|---|---|
| Claude (Sonnet 4.5) | 200K tokens | ~50,000 lines |
| GPT-4o | 128K tokens | ~32,000 lines |
| GPT-4 Turbo | 128K tokens | ~32,000 lines |
This isn't just a spec sheet number. It changes how you can work.
Real Impact: Full Codebase Context
With Claude, you can paste an entire microservice codebase into context. Routes, models, services, utilities — all of it. Then ask:
"Add user authentication to this codebase. Show me all the files I need to create or modify."
Claude can see the relationships between files, understand your naming conventions, and generate coherent code that fits your existing patterns.
With GPT-4's 128K limit, you're more likely to hit context boundaries on larger projects. You'll need to be selective about what you include, which means the AI might miss important context.
Long Conversation Coherence
Even within the context limit, Claude maintains coherence better in long conversations. After 50 back-and-forth exchanges, Claude still remembers what you discussed at the beginning. GPT-4 tends to lose the thread — you'll find yourself re-explaining decisions you made an hour ago.
Winner: Claude — 200K context is a genuine advantage for serious development.
5. API Pricing for Developers
If you're building with these models, cost matters.
| Model | Input (per 1M tokens) | Output (per 1M tokens) | Best For |
|---|---|---|---|
| Claude Haiku 4.5 | $1 | $5 | Fast, cheap tasks |
| Claude Sonnet 4.5 | $3 | $15 | Balanced (recommended) |
| Claude Opus 4.5 | $5 | $25 | Maximum capability |
| GPT-4o | $2.50 | $10 | Good general use |
| GPT-4o mini | $0.15 | $0.60 | Very cheap, less capable |
| GPT-4 Turbo | $10 | $30 | Legacy, expensive |
Cost Analysis
For coding tasks specifically:
- If you're doing high-volume, simple tasks (autocomplete, basic refactoring): GPT-4o mini or Claude Haiku — massive cost savings.
- If you need quality code generation: Claude Sonnet is slightly pricier than GPT-4o but produces better code, potentially reducing iteration costs.
- For complex architecture work: Claude Opus is expensive but the quality difference on hard problems can be worth it.
The Hidden Cost: Iteration
GPT-4 code often needs more back-and-forth to get right. That cheaper per-token cost can be deceiving if you're making 3-4 requests to get usable code vs. Claude's 1-2.
Verdict: Comparable pricing, but Claude's higher quality per request often means lower total cost.
6. IDE Integrations: Where You'll Actually Use These
| IDE/Tool | Claude Support | GPT-4 Support |
|---|---|---|
| GitHub Copilot | ✅ (Sonnet as option) | ✅ Native |
| Cursor | ✅ Default choice | ✅ Available |
| VS Code (Continue) | ✅ Yes | ✅ Yes |
| JetBrains | ✅ Via plugins | ✅ Via Copilot/plugins |
| Claude Code (terminal) | ✅ Native | ❌ No |
| Code Interpreter | ⚠️ Artifacts (limited) | ✅ Full support |
Cursor: Where Claude Shines
Cursor, the AI-first IDE that hit $9B valuation, uses Claude as its primary model. There's a reason — Claude's code generation quality and context handling make it the best experience for Cursor's multi-file editing.
Claude Code: The Terminal Power User Tool
Claude Code is unique. It's a terminal-based agentic coding assistant that:
- Sees your entire project
- Creates and modifies multiple files
- Runs commands and tests
- Commits to git
- Iterates based on results
There's no GPT-4 equivalent. If you're a senior developer comfortable in the terminal, Claude Code is genuinely transformative.
GitHub Copilot: The Ecosystem Champion
Copilot works everywhere — VS Code, JetBrains, Neovim, Visual Studio. It now offers Claude as a model option, but GPT-4 is still the default. If you're locked into an IDE that only supports Copilot, you'll get GPT-4 unless you explicitly switch.
Winner: Depends on your workflow. Claude Code users → Claude. Copilot users → GPT-4 by default.
For a comprehensive comparison of all major coding assistants (including Cody, Windsurf, and more), check our GitHub Copilot vs Cursor vs Cody guide.
7. Artifacts vs Canvas: Visual Development Features
Both platforms now offer visual, interactive coding environments.
Claude's Artifacts
Artifacts let you see code rendered live. Write a React component, see it running. Build a chart, see the visualization. It's particularly good for:
- Prototyping UI components
- Creating visualizations
- Interactive demonstrations
- SVG and canvas work
Artifacts feel like a scratchpad for developers — quick iteration with visual feedback.
ChatGPT's Canvas
Canvas is more of a collaborative document editor. It's good for:
- Long-form code with inline comments
- Iterative editing within the document
- Explaining code with prose alongside it
Canvas feels more like a code review tool than a development environment.
Code Interpreter (ChatGPT Only)
This is GPT-4's unique advantage. Code Interpreter can actually execute Python code, analyze data, create plots, and work with files. Claude can't do this — Artifacts show previews but don't run server-side code.
For data science, analysis, and "run this and show me the output" workflows, Code Interpreter is genuinely useful.
Winner: GPT-4 for execution, Claude for preview/prototyping.
Real-World Usage: When to Use Each
| Task | Use | Why |
|---|---|---|
| Building a new feature | Claude | Better code quality, fewer iterations |
| Quick one-liner | GPT-4 | Faster, more concise |
| Debugging production issue | Claude | More thorough analysis |
| Code review | Claude | Catches subtle issues |
| Explaining legacy code | Either | Both good at explanation |
| Data analysis | GPT-4 | Code Interpreter executes |
| Full codebase refactor | Claude | Larger context, better coherence |
| Learning a new framework | Either | Both handle documentation well |
| Writing tests | Claude | Considers more edge cases |
| API prototyping | GPT-4 | Code Interpreter for quick testing |
The Verdict: Which AI Writes Better Code?
Claude writes better code.
For everything that matters in professional software development — code quality, debugging, code review, handling large codebases — Claude has a meaningful edge. The code is cleaner, more production-ready, and requires fewer iterations.
But GPT-4 has real strengths:
- Speed — For quick tasks, GPT-4 is faster and more concise
- Ecosystem — More IDE integrations, Code Interpreter, broader tool support
- Execution — Code Interpreter actually runs code; Claude can't
My Recommendation
For professional development: Start with Claude. Use Claude Code if you're comfortable in the terminal, or Cursor with Claude for a full IDE experience.
For quick tasks and prototyping: GPT-4 is fine. The speed advantage matters for small things.
For data science: GPT-4 with Code Interpreter is genuinely better — execution matters.
For learning: Either works well. Pick the one you find more pleasant to interact with.
The Bottom Line
If you're writing production code and care about quality, Claude is the better choice in 2026. The gap isn't huge, but it's consistent — and consistent quality advantages compound over time.
GPT-4 remains excellent and has ecosystem advantages that matter for many workflows. But for pure coding ability? Claude has taken the lead.
Looking for free coding assistance? Check our best free AI tools guide for budget-friendly options.
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Keep Reading
- Claude vs ChatGPT for Coding
- 7 Best AI Coding Assistants Ranked
- ChatGPT vs Claude: Which Should You Use?
- Cursor vs GitHub Copilot 2026
- Best AI Coding Assistants 2026
- AI Coding Agents: Cursor vs Windsurf vs Claude Code vs Codex
Last updated: February 2026
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