# crates.version

**stable** **Standard**

Metadata of one specific crate version.

`GET /v1/crates/version`

## What you get

One crates.io record in Onekey's unified shape, in `data`. If the record does not exist you get a `404 not_found` and are not charged.

## What it costs

- **Standard · 1 credit** for a fresh fetch, charged only when it succeeds.
- **Free when served from cache (0.2 credit for a cached response over 100 KB).**
- **Free** if the request is invalid (never charged) or the source fails or reports not found (refunded).

## Parameters

| Name | Type | Required | Default | What it is | Constraints |
| --- | --- | --- | --- | --- | --- |
| `name` | string | yes | (required) | crates.io crate name, e.g. serde | max 64 chars; must match `[a-z0-9_-]{1,64}`; trimmed, lowercased |
| `version` | string | yes | (required) | Exact crate version, e.g. 1.0.200 | max 64 chars; must match `[0-9A-Za-z][0-9A-Za-z.+-]{0,63}`; trimmed |

## Request

```bash
curl "https://api.onekey.dev/v1/crates/version?name=serde&version=1.0.200" \
  -H "x-api-key: YOUR_API_KEY"
```

```python
import requests

res = requests.get(
    "https://api.onekey.dev/v1/crates/version",
    params={"name": "serde", "version": "1.0.200"},
    headers={"x-api-key": "YOUR_API_KEY"},
)
body = res.json()

if body["success"]:
    print(body["data"])
else:
    print(body["error"]["code"], body["error"]["message"])
```

```javascript
const params = new URLSearchParams({ name: "serde", version: "1.0.200" });
const res = await fetch(`https://api.onekey.dev/v1/crates/version?${params}`, {
  headers: { "x-api-key": "YOUR_API_KEY" },
});
const body = await res.json();

if (body.success) console.log(body.data);
else console.error(body.error.code, body.error.message);
```

## Recorded response

A real crates.io response, recorded and returned in Onekey's shape. Fields the platform does not provide are `null`.

```json
{
  "success": true,
  "data": {
    "entity": {
      "name": "serde",
      "createdAt": "2024-05-01T16:00:47Z",
      "stats": {
        "downloads": 3433543
      }
    },
    "package": {
      "version": "1.0.200",
      "license": "MIT OR Apache-2.0",
      "yanked": false
    },
    "ext": {
      "rustVersion": "1.31",
      "edition": "2018"
    },
    "author": {
      "username": "dtolnay"
    }
  },
  "metadata": {
    "platform": "crates",
    "endpoint": "version",
    "cached": false,
    "stale": false,
    "age_s": 0,
    "fetched_at": "2026-01-01T12:00:00+00:00",
    "credits_charged": 1,
    "request_id": "7f3a9c2e5b1d4c8fa2e6d0b9c4f18e37"
  },
  "error": null
}
```

## Field mapping

How this endpoint's source fields become Onekey's [unified schema](https://onekey.dev/docs/schema.md). Fields the source lacks come back as `null`.

| Source path | Onekey field | Transform |
| --- | --- | --- |
| `version.crate` | `entity.name` | - |
| `version.num` | `package.version` | - |
| `version.created_at` | `entity.createdAt` | `toIsoDate` |
| `version.downloads` | `entity.stats.downloads` | `toNumber` |
| `version.license` | `package.license` | - |
| `version.yanked` | `package.yanked` | `toBoolean` |
| `version.rust_version` | `ext.rustVersion` | - |
| `version.edition` | `ext.edition` | - |
| `version.published_by.login` | `author.username` | - |

## Caching and freshness

- Fresh for about 1 hour. Repeat calls in that window are served from cache and are free.
- Between 1 hour and 1 day the cached copy is still served instantly and marked `stale: true` while Onekey refreshes it in the background.
- If the source is down when a refresh is needed, the last copy can be served for up to 3 days more (marked stale).
- A "not found" is remembered for 5 minutes and is free.
- The cache is shared across all customers, which is what keeps repeat calls cheap.

## What can go wrong

| Status | Code | What to do |
| --- | --- | --- |
| 401 | `unauthorized` | Check the `x-api-key` header. |
| 402 | `insufficient_credits` | [Add credits](https://onekey.dev/pricing); your balance must cover the price. |
| 404 | `not_found` | That record does not exist. Free; do not retry. |
| 422 | `invalid_params` | Fix the parameters using the table above. Free. |
| 429 | `rate_limited` | Wait `Retry-After` seconds, then retry. |
| 502 | `upstream_error` | The source failed. Refunded; retry with backoff. |

See [Errors](https://onekey.dev/docs/errors.md) for the full list and retry guidance.

Status: stable (verified against the live source).