# Claude Sonnet 5 — API, capabilities & pricing | Y-API

> Claude Sonnet 5 is Anthropic’s Sonnet-class model for coding and professional work. The reviewed reference describes adaptive thinking and an updated tokenizer, so migration involves more than changing a display name.

This is the markdown representation of https://y-api.bestvirtualgoods.com/models/anthropic/claude-sonnet-5. Generated by `scripts/generate-seo-assets.mjs` from the same copy the page renders — do not edit by hand.

Model ID: `anthropic/claude-sonnet-5`

Sources reviewed: 2026-10-04. Y-API catalog snapshot: 2026-10-04.

## Choosing this model

Selection advice by Y-API. The checks below are suggested evaluations, not published test results.

### Where to start

Evaluate it for day-to-day pull requests, code explanations and document analysis with explicit acceptance criteria. Keep hard cases for comparison with Opus instead of routing every request to the same tier.

### What to watch for

Do not reuse token-count assumptions from an older Claude tokenizer. Nor should you assume every sampling option is accepted: the reviewed parameter list does not include temperature for this entry.

## Model specifications

These are OpenRouter model-level specifications, not a Y-API compatibility test. A particular route may accept fewer input formats, parameters or tokens. Verify the features you need with a small request; a successful text response does not validate vision or tool calling.

| Field | Value |
| --- | --- |
| Context window | 1,000,000 tokens |
| Input | Text, Image, File |
| Output | Text |
| Listed on OpenRouter | 2026-06-30 |
| Parameters listed by OpenRouter | `include_reasoning`, `max_completion_tokens`, `max_tokens`, `reasoning`, `reasoning_effort`, `response_format`, `stop`, `structured_outputs`, `tool_choice`, `tools`, `verbosity` |

## Estimate your cost

| Price basis | Input / 1M tokens | Output / 1M tokens |
| --- | --- | --- |
| Account credit | $2.00 | $10.00 |
| Cash equivalent | $0.20 | $1.00 |

$1 paid adds $10 of credit. Cash equivalent = credit consumed ÷ 10; this is not the model publisher’s list price.

Input tokens / request: 1000. Output tokens / request: 500. Number of requests: 1000.

Estimated credit consumed: $7.00. Estimated cash equivalent: $0.70.

Illustrative token budget, not measured usage or a quote. Includes input and output; excludes separate media charges, cache discounts and retries. Include billed reasoning tokens in your output budget where applicable. Actual billing follows usage returned by the service.

### Same token budget, different models

| Model | Estimated credit consumed | Estimated cash equivalent |
| --- | --- | --- |
| [Claude Sonnet 5](https://y-api.bestvirtualgoods.com/models/anthropic/claude-sonnet-5) | $7.00 | $0.70 |
| [Claude Opus 5](https://y-api.bestvirtualgoods.com/models/anthropic/claude-opus-5) | $17.50 | $1.75 |
| [GLM 5.3](https://y-api.bestvirtualgoods.com/models/z-ai/glm-5.3) | $3.90 | $0.39 |

## Use the API

These minimal, text-only requests use the exact Y-API model ID. They do not demonstrate image, audio, video, file or tool support. The output limit also needs room for reasoning; an empty answer with finish_reason=length can mean the budget was exhausted.

Set the TOKEN environment variable to a key from your console. Run this on your server or locally; never expose a key in browser code or a public repository.

### A task to try

Review a retry loop that retries every HTTP error three times. Explain which error classes should not be retried and propose bounded backoff behavior.

```bash
curl --fail-with-body --silent --show-error --max-time 120 \
  'https://api.y-api.bestvirtualgoods.com/v1/chat/completions' \
  -H "Authorization: Bearer ${TOKEN:?Set TOKEN first}" \
  -H 'Content-Type: application/json' \
  --data-binary @- <<'JSON'
{
  "model": "anthropic/claude-sonnet-5",
  "messages": [
    {
      "role": "user",
      "content": "Review a retry loop that retries every HTTP error three times. Explain which error classes should not be retried and propose bounded backoff behavior."
    }
  ],
  "max_tokens": 4096
}
JSON
```

```python
import json
import os
import sys
import urllib.error
import urllib.request

payload = {
  "model": "anthropic/claude-sonnet-5",
  "messages": [
    {
      "role": "user",
      "content": "Review a retry loop that retries every HTTP error three times. Explain which error classes should not be retried and propose bounded backoff behavior."
    }
  ],
  "max_tokens": 4096
}

request = urllib.request.Request(
    "https://api.y-api.bestvirtualgoods.com/v1/chat/completions",
    data=json.dumps(payload).encode("utf-8"),
    headers={
        "Authorization": "Bearer " + os.environ["TOKEN"],
        "Content-Type": "application/json",
    },
    method="POST",
)
try:
    with urllib.request.urlopen(request, timeout=120) as response:
        result = json.load(response)
    print(json.dumps(result, ensure_ascii=False, indent=2))
except urllib.error.HTTPError as error:
    print(error.read().decode("utf-8"), file=sys.stderr)
    raise SystemExit(1)
```

### How to evaluate the result

Distinguish transient failures from authentication and validation errors. For writes, require idempotency before retries; check that the proposal limits both attempts and elapsed time.

## Before you choose

### Can I copy all of my older Claude parameters?

Do not assume so. Start with the minimal request, then add each needed option. The tokenizer and the accepted parameter set can differ from earlier models or from a native Anthropic endpoint.

## Sources & scope

Technical facts come from the cited model page and, where available, its linked publisher card. A card describes that checkpoint; it is not proof of the weights a gateway serves. Prices come only from the Y-API catalog. We do not claim measured latency, uptime or benchmark scores for this endpoint.

- [OpenRouter model page & specifications](https://openrouter.ai/anthropic/claude-sonnet-5)
- [Y-API catalog & prices (JSON)](https://y-api.bestvirtualgoods.com/models.json)

## Models to compare

Compare these alternatives on the same inputs. Their descriptions explain different roles; a lower price does not establish equivalent quality.

### [Claude Opus 5](https://y-api.bestvirtualgoods.com/models/anthropic/claude-opus-5)

Claude Opus 5 is positioned by OpenRouter as Anthropic’s model for demanding reasoning, software engineering and extended agent work. The reference entry lists text, image and file input with text output.

### [GLM 5.3](https://y-api.bestvirtualgoods.com/models/z-ai/glm-5.3)

GLM 5.3 builds on the GLM 5.2 base model with revised post-training for complex coding and long-running tasks. OpenRouter documents always-on reasoning for this entry, a meaningful distinction when budgeting output.

## Links

- HTML version of this page: https://y-api.bestvirtualgoods.com/models/anthropic/claude-sonnet-5
- Site index for agents: https://y-api.bestvirtualgoods.com/llms.txt
- Full reference (single file): https://y-api.bestvirtualgoods.com/llms-full.txt
- OpenAPI 3.1 spec: https://y-api.bestvirtualgoods.com/openapi.json
- Model catalog (JSON, no key needed): https://y-api.bestvirtualgoods.com/models.json
- API base URL: `https://api.y-api.bestvirtualgoods.com/v1`
- Contact: support@bestvirtualgoods.com
- Model catalog: https://y-api.bestvirtualgoods.com/models
- Integration guide: https://y-api.bestvirtualgoods.com/docs