Version: Next

HTTP compression

The Apify client compresses request bodies before sending them to the API. It reduces the amount of data transferred over the network, resulting in faster requests and lower bandwidth usage, especially for large payloads such as Actor inputs, dataset uploads, or key-value store records.

How it works

The client compresses request bodies using the compressor configured via the compression parameter (default 'gzip'). The server supports both gzip and brotli and decompresses the request body transparently. A body is compressed only when it's large enough to benefit, its content type isn't already compressed, and the request carries no Content-Encoding of its own. For details, see Minimum body size, Already-compressed payloads, and Pre-compressed bodies.

Minimum body size

The client sends bodies smaller than 1024 bytes without compression and without the Content-Encoding header. A body of this size fits in one network packet, so compression doesn't remove a network round trip and only costs CPU time. For very small bodies, the compression format adds bytes and can make the body larger.

Already-compressed payloads

Some payloads carry their own compression, so compressing them again costs CPU and memory while making the request slightly larger. The client skips compression when the request's Content-Type is one of these:

any image/*, audio/*, or video/* type
archives such as application/zip, application/gzip, or application/x-7z-compressed
office documents and packages built on ZIP, such as .docx, .xlsx, .epub, or .apk
web fonts (font/woff, font/woff2)

Two kinds of media type are compressed anyway: raw formats such as image/bmp, image/tiff, and audio/wav, and subtypes with a structured syntax suffix such as image/svg+xml. Set an accurate content_type when uploading media to a key-value store:

Async client
Sync client

import asyncio
from pathlib import Path

from apify_client import ApifyClientAsync

TOKEN = 'MY-APIFY-TOKEN'


async def main() -> None:
    apify_client = ApifyClientAsync(TOKEN)
    kvs_client = apify_client.key_value_store('MY-KVS-ID')

    screenshot = await asyncio.to_thread(Path('screenshot.png').read_bytes)

    # The explicit content type lets the client skip compressing the PNG.
    await kvs_client.set_record('screenshot', screenshot, content_type='image/png')


if __name__ == '__main__':
    asyncio.run(main())

from pathlib import Path

from apify_client import ApifyClient

TOKEN = 'MY-APIFY-TOKEN'


def main() -> None:
    apify_client = ApifyClient(TOKEN)
    kvs_client = apify_client.key_value_store('MY-KVS-ID')

    screenshot = Path('screenshot.png').read_bytes()

    # The explicit content type lets the client skip compressing the PNG.
    kvs_client.set_record('screenshot', screenshot, content_type='image/png')

Without an explicit content type, a bytes value is sent as application/octet-stream, which the client can't tell apart from uncompressed binary data and therefore still compresses. File-like values are read into memory before they're sent, so they follow the same rules as any other body.

Pre-compressed bodies

A payload can reach the client already encoded, for example a gzipped file read from disk. Set the Content-Encoding header to name the encoding the payload carries. The client then sends the body as it is and forwards the header, so nothing gets compressed twice. set_record exposes the header as its content_encoding argument:

Async client
Sync client

import asyncio
import gzip
from pathlib import Path

from apify_client import ApifyClientAsync

TOKEN = 'MY-APIFY-TOKEN'


async def main() -> None:
    apify_client = ApifyClientAsync(TOKEN)
    kvs_client = apify_client.key_value_store('MY-KVS-ID')

    report = await asyncio.to_thread(Path('report.csv').read_bytes)
    compressed_report = await asyncio.to_thread(gzip.compress, report)

    # The explicit content encoding stops the client from compressing the bytes again.
    await kvs_client.set_record(
        'report',
        compressed_report,
        content_type='text/csv',
        content_encoding='gzip',
    )


if __name__ == '__main__':
    asyncio.run(main())

import gzip
from pathlib import Path

from apify_client import ApifyClient

TOKEN = 'MY-APIFY-TOKEN'


def main() -> None:
    apify_client = ApifyClient(TOKEN)
    kvs_client = apify_client.key_value_store('MY-KVS-ID')

    report = Path('report.csv').read_bytes()
    compressed_report = gzip.compress(report)

    # The explicit content encoding stops the client from compressing the bytes again.
    kvs_client.set_record(
        'report',
        compressed_report,
        content_type='text/csv',
        content_encoding='gzip',
    )

The header is forwarded verbatim, so it also covers encodings the client ships no compressor for, such as deflate. The API accepts gzip, br, deflate, and identity. Passing identity turns compression off for a single request without changing how the client is configured.

A value that can't be compressed at all - a string, an object serialized to JSON, or a file-like value opened in text mode - is rejected with a TypeError when content_encoding names a compression. Beyond that the client can't verify that the bytes match the header, so set Content-Encoding only when the payload really is encoded that way. Key-value store records are stored exactly as you upload them, which makes the header part of the stored record rather than a transport detail.

Configuration

To choose the compression algorithm, pass compression to the client constructor:

from apify_client import ApifyClient

# Default: gzip, no extra dependency required
client = ApifyClient(token='MY-APIFY-TOKEN')

# Opt in to brotli (requires apify-client[brotli])
client = ApifyClient(token='MY-APIFY-TOKEN', compression='brotli')

Enabling brotli

Brotli is available as an optional extra. Install it alongside the client:

pip install "apify-client[brotli]"
# or
uv add "apify-client[brotli]"

Then pass compression='brotli' to the client constructor. If you request brotli without installing the extra, the client raises a clear ImportError. There is no silent fallback.

Custom quality and advanced control

For fine-grained control over compression quality, inject an HttpCompressor instance directly instead of a string literal:

from apify_client import ApifyClient
from apify_client.http_compressors import BrotliHttpCompressor, GzipHttpCompressor

# Brotli at maximum quality
client = ApifyClient(token='MY-APIFY-TOKEN', compression=BrotliHttpCompressor(quality=11))

# Gzip at maximum quality
client = ApifyClient(token='MY-APIFY-TOKEN', compression=GzipHttpCompressor(quality=9))

You can also implement a fully custom compressor by subclassing HttpCompressor. The client calls it only for bodies that reach the minimum body size and aren't already compressed or pre-compressed by the caller:

from apify_client import ApifyClient
from apify_client.http_compressors import HttpCompressor


class IdentityCompressor(HttpCompressor):
    content_encoding = 'identity'
    """Value sent in the `Content-Encoding` header."""

    def compress(self, data: bytes) -> bytes:
        """Compress a request body.

        Args:
            data: The raw bytes to compress.

        Returns:
            The compressed bytes.
        """
        return data


client = ApifyClient(token='MY-APIFY-TOKEN', compression=IdentityCompressor())

Comparison

	Brotli	Gzip
Compression ratio	Typically better than gzip	Good
CPU cost	Moderate, depends on quality	Low
Availability	Requires the `brotli` extra	Built-in, no extra needed
`Content-Encoding` header	`br`	`gzip`
Quality range	`0–11`	`1–9`
Default quality	`6`	`9`
Enable via config	`compression='brotli'`	`compression='gzip'` (default)
Best for	Large payloads where bandwidth matters	Minimal-dependency environments

tip

For most workloads, the bandwidth savings from brotli outweigh the CPU costs. Install the brotli extra and pass compression='brotli' unless you can't install additional packages in your environment.