A side-by-side comparison of Claude Opus 4.8 and Claude Sonnet 5: input/output pricing, capabilities and available endpoints, served live from 188pay.ai. Both are reachable with the same API key.
| Item | Claude Opus 4.8 | Claude Sonnet 5 |
|---|---|---|
| Input (per 1M tokens) | $4.5 | $1.8 |
| Output (per 1M tokens) | $22.5 | $9 |
| Cache read (per 1M tokens) | $0.45 | $0.18 |
| Cache write 5m (per 1M tokens) | $5.625 | $2.25 |
| Item | Claude Opus 4.8 | Claude Sonnet 5 |
|---|---|---|
| Context window | 1,000,000 | 1,000,000 |
| Max output | 128,000 | — |
| Item | Claude Opus 4.8 | Claude Sonnet 5 |
|---|---|---|
| function_calling | Yes | Yes |
| prompt_caching | Yes | Yes |
| vision | Yes | Yes |
On input, Claude Sonnet 5 is cheaper ($4.5 vs $1.8 per 1M tokens). On output, Claude Sonnet 5 is cheaper ($22.5 vs $9 per 1M tokens). All prices are per million tokens in USD.
both support function_calling, prompt_caching, vision.
Yes. Both are available on 188pay.ai through one API key and the same OpenAI-compatible endpoint — switching means changing the model field from "claude-opus-4-8" to "claude-sonnet-5", nothing else.
Both are available on 188pay.ai under one API key — switching between them means changing the model field and nothing else, so you can use each where it fits rather than picking one.