> ## Documentation index > Fetch the complete documentation index at: https://upstash.com/docs/llms.txt > Ask it with GET https://upstash.com/docs/ask?q=. Short keywords rank best. > Use these to discover all available pages before exploring further. > Feature requests: https://upstash.com/docs/common/help/feature-requests.md lists what users asked for and how to vote for a request or add one. > Page rating: `GET https://upstash.com/docs/feedback?path=/docs/blob/reference/types&helpful=true` (or `false`) records whether this page helped. An optional `comment` (URL-encoded, at most 500 characters) says what was missing or wrong. It is anonymous and needs no key. Comments hold no code, secrets or personal data. # Types > Size, Duration, CacheOption, the record types, and the phases an upload moves through. The option and record types the rest of these docs refer to, and the upload phases named in error messages. --- ## Size ```ts TypeScript maxSize: 4096 // 4,096 bytes maxSize: "20MB" // 20,000,000 bytes maxSize: "32MiB" // 33,554,432 bytes multipart: "100MB" ``` ```python Python max_size=4096 # 4,096 bytes max_size="20MB" # 20,000,000 bytes max_size="32MiB" # 33,554,432 bytes multipart="100MB" ``` ```go Go MaxSize: 4096 // 4,096 bytes MaxSize: 20 * blob.MB // 20,000,000 bytes MaxSize: 32 * blob.MiB // 33,554,432 bytes Multipart: blob.MultipartOver(100 * blob.MB) ``` A byte count, never a bit count. A bare number is bytes. String units ignore case, so `MB` and `mb` both mean megabytes. | Units | Base | Example | | --- | --- | --- | | `B`, `KB`, `MB`, `GB`, `TB` | Decimal, powers of 1,000 | `"32MB"` = 32,000,000 bytes | | `KiB`, `MiB`, `GiB`, `TiB` | Binary, powers of 1,024 | `"32MiB"` = 33,554,432 bytes | For a 32 MiB file limit, use `"32MiB"` or `33554432`. A `"32MB"` limit is smaller and rejects that file. Existing decimal units keep their values. Bit units such as `mbit` and `Mbps` are not supported. An unparseable size throws where the option is written, not per request. In Go a size is an `int64` of bytes written with the unit constants, and `blob.ParseSize` reads the string form from configuration. A limit you write by hand takes a size: the max size, the multipart threshold. A measurement you forward is a plain number of bytes: the size option on `put`, and every size the SDK returns. `formatBytes`, exported from every TypeScript entrypoint, always displays decimal byte units, including values supplied as MiB: `formatBytes(2_400_000)` is `2.4 MB`. --- ## Duration ```ts TypeScript expiresIn: 300 // 5 minutes expiresIn: "5m" olderThan: "7d" cache: "1h" ``` ```python Python expires_in=300 # 5 minutes expires_in="5m" expires_in=timedelta(minutes=5) older_than="7d" cache="1h" ``` ```go Go ExpiresIn: 5 * time.Minute olderThan := 7 * 24 * time.Hour Cache: "1h" ``` A span of time. A bare number is **seconds**; a string takes a unit: `ms`, `s`, `m`, `h`, `d`, or a long form (`sec`, `seconds`, `min`, `minutes`, `hr`, `hours`, `day`, `days`). A string with no unit is seconds. An unparseable duration throws an error naming the option. In Go a lifetime or window is a `time.Duration`; only `Cache` takes the string form. --- ## CacheOption ```ts TypeScript cache: "immutable" cache: "revalidate" cache: "no-store" cache: "15m" cache: "public, max-age=60, s-maxage=31536000" ``` ```python Python cache="immutable" cache="revalidate" cache="no-store" cache="15m" cache="public, max-age=60, s-maxage=31536000" ``` ```go Go Cache: blob.CacheImmutable // "immutable" Cache: blob.CacheRevalidate // "revalidate" Cache: blob.CacheNoStore // "no-store" Cache: "15m" Cache: "public, max-age=60, s-maxage=31536000" ``` One of three words, a duration, or a raw `Cache-Control` header. The header each one stores is on [Caching](/blob/bucket/caching#the-cache-option). How each SDK types these three: [TypeScript](/blob/sdks/ts/overview#option-types), [Python](/blob/sdks/py/overview#option-types), [Go](/blob/sdks/go/overview#option-types). --- ## Records Four record shapes come back from the SDK. They nest. | Record | Fields | Returned by | | --- | --- | --- | | Object | path, URL, versioned URL, size, etag, uploaded at | `list`, `copy`, `move`, the JSON update | | Completed object | an object plus content type | `put`, the completion callback, a finished browser upload | | Info | an object plus content type and metadata | `info` | | Download | info plus the body | `get` | Object fields: | Field | Description | | --- | --- | | Path | The object's key. | | URL | The public object URL. Not set on a private bucket. | | Versioned URL | The URL with `?v=`, etag percent-encoded. Not set when the URL is not. | | Size | Bytes. | | Etag | Storage's etag, quoted: `"9f3c..."`. | | Uploaded at | Last modified. | Across the SDK, `blob` names a record, never the bytes. Bytes go in and come out as `body` (`content` on Python's `get`). The type names and field types in each SDK: [TypeScript](/blob/sdks/ts/bucket#records), [Python](/blob/sdks/py/bucket#records), [Go](/blob/sdks/go/bucket#records). --- ## Upload phases A direct browser upload makes up to four kinds of request to your upload route. The names appear in error messages and across these docs. | Phase | When | What your route does | | --- | --- | --- | | `begin` | First request, once | Checks constraints, runs the before-upload callback, signs the first URL(s). Never retried. | | `parts` | Multipart only, as needed | Signs the next batch of part URLs. | | `end` | Once the bytes landed | Completes the upload, runs the completion callback. Retried by the browser on failure. | | `cancel` | On `cancel()` | Aborts the multipart upload, or deletes the single-PUT object. | Every request and every successful answer carries `protocol`, the version of this exchange, in the JSON body. It is separate from the package version, so a browser bundle and a server on different SDK releases, or a server written with another server SDK, still understand each other. A missing value means `1`, changes are only ever additive, and neither side refuses the other's version. The PUTs that carry the bytes go to storage, never to your route. [How signing works](/blob/reference/signing#the-direct-upload-handshake) has the full handshake.