Claude Opus 4.8 vs Kimi K3for coding

The verdict

Dead heat: 89 each

Same 18 coding tasks, marked blind by three rival labs. Tested 16 Aug 2026.

Where they differed most

The task — Typed debounce

Write a debounce function in TypeScript that preserves the argument types of the wrapped function, returns a function with a .cancel() method, and does not use 'any'. Explain in one sentence why the naive generic signature loses type information.

Claude Opus 4.85/10

# Debounce Function

```typescript
type Debounced<TArgs extends unknown[]> = {
  (...args: TArgs): void;
  cancel(): void;
};

function debounce<TArgs extends unknown[]>(
  fn: (...args: TArgs) => unknown,
  delay: number
): Debounced<TArgs> {
  let timer: ReturnType<typeof setTimeout> | undefined;

  const debounced = (...args: TArgs): void => {
    if (timer !== undefined) {
      clearTimeout(timer);
    }
    timer = setTimeout(() => {
      timer = undefined;
      fn(...args);
    }, delay);
  };

  debounced.cancel = (): void => {
    if…

Kimi K310/10

```typescript
type Debounced<Args extends unknown[]> = ((...args: Args) => void) & {
  cancel(): void;
};

function debounce<Args extends unknown[]>(
  fn: (...args: Args) => unknown,
  wait: number
): Debounced<Args> {
  let timer: ReturnType<typeof setTimeout> | undefined;

  const clear = (): void => {
    if (timer !== undefined) {
      clearTimeout(timer);
      timer = undefined;
    }
  };

  return Object.assign(
    (...args: Args): void => {
      clear();
      timer = setTimeout(() => {
        timer = undefined;
        fn(...args…

Task by task

Task	Claude Opus 4.8	Kimi K3
Duration parser	9	10
Find the bug	10	10
SQL without window functions	10	10
Infinite useEffect	10	9
Typed debounce	5	10
Leftmost binary search	10	8
Security review	9	9
Safe migration	8	9
Fix the code not the test	10	9
Race condition	9	9
Retry with backoff	9	5
Recursive type	10	8
Bash one-liner	9	9
Explain and cost	10	9
Regex with limits	9	10
Callback to async	9	8
Diagnose from a trace	9	9
Idempotency	6	9

Full receipts: Claude Opus 4.8, Kimi K3 · judges gemini-3.1-pro-preview, gpt-5.6-terra, grok-4.5

Questions people ask

Which is better for coding: Claude Opus 4.8 or Kimi K3?

They tied at 89/100 on our coding suite — for this job, pick on price or the product you already use.

How was this tested?

Both models answered the identical published coding tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.

More coding head-to-heads: Claude Opus 4.8 vs GPT-5.6 Luna · GPT-5.6 Luna vs Kimi K3 · Claude Opus 4.8 vs GPT-5.6 Sol · GPT-5.6 Sol vs Kimi K3 · Claude Opus 4.8 vs GPT-5.6 Terra · GPT-5.6 Terra vs Kimi K3

Full ranking: Best AI for coding · model pages: Claude Opus 4.8, Kimi K3