blitzjson

Drop-in replacement for Python's json module with native Django type support. Built with Rust via PyO3 for maximum performance.

Features

Drop-in replacement: Same API as json.dumps(), json.loads(), etc.
Native Django types: Handles datetime, date, time, timedelta, UUID, Decimal, QuerySet, Model, Promise without custom encoders
Rust-powered: Direct serialization to JSON buffer via CPython FFI, no intermediate Python objects
Zero dependencies: No runtime Python dependencies required
Full json API: ensure_ascii, indent, sort_keys, allow_nan, default (recursive)
Streaming: stream_dump_queryset() for memory-efficient large QuerySet serialization
Django integration: BlitzJsonResponse, BlitzJSONEncoder, install() monkey-patch

Installation

pip install blitzjson

Quick Start

# Before
import json
from datetime import datetime

json.dumps({"created": datetime.now()})  # TypeError!

# After
import blitzjson as json

json.dumps({"created": datetime.now()})  # Works!

Monkey-patching (try before you commit)

If you want to test blitzjson in your existing project without changing any import json statements, use the install() function to monkey-patch Python's built-in json module:

# In your settings.py or at the top of manage.py
import blitzjson
blitzjson.install()

# Now ALL code that uses `import json` will use blitzjson instead
import json
json.dumps({"created": datetime.now()})  # Works! No TypeError!

Or test it interactively:

>>> import blitzjson
>>> blitzjson.install()
>>> import json
>>> json.dumps({"created": datetime.now(), "uuid": uuid4()})
'{"created": "2024-01-15T10:30:45+00:00", "uuid": "550e8400-e29b-41d4-a716-446655440000"}'

>>> # Revert when done testing
>>> blitzjson.uninstall()

Supported Types

Python Type	JSON Output	Example
`datetime`	ISO 8601 string	`"2024-01-15T10:30:45Z"`
`date`	ISO date string	`"2024-01-15"`
`time`	ISO time string	`"10:30:45"`
`timedelta`	ISO 8601 duration	`"P1DT2H3M4S"`
`UUID`	Hyphenated string	`"550e8400-e29b-41d4-a716-446655440000"`
`Decimal`	String (precision-safe)	`"123.456789012345678901"`
`bytes`	Base64 string	`"aGVsbG8="`
`set/frozenset`	Array	`[1, 2, 3]`
`enum`	Value	`"value"`
`dataclass`	Object	`{"field": "value"}`

Django-Specific

Django Type	JSON Output
`QuerySet`	Array of model dicts
`Model`	Dict of field values
`Promise` (lazy strings)	String

API

`dumps(obj, **kwargs)`

import blitzjson as json

# Standard usage
json.dumps({"key": "value"})

# With Django types
json.dumps({"created": datetime.now(), "uuid": uuid4()})

`loads(s, **kwargs)`

obj = json.loads('{"key": "value"}')

# With object_hook
obj = json.loads('{"key": "value"}', object_hook=lambda d: {k.upper(): v for k, v in d.items()})

`dump(obj, fp, kwargs)` / `load(fp, kwargs)`

File-based serialization/deserialization.

`dumpb(obj, pretty=False)`

Serialize to bytes (faster than dumps for network responses).

`dump_queryset(queryset)` / `dump_queryset_bytes(queryset)`

Optimized serialization for Django QuerySets.

Benchmarks

vs json + DjangoJSONEncoder (CPython 3.14, Linux x86_64, consumer hardware):

Note: Benchmarks run on consumer hardware (AMD Ryzen 9 7900X). CI runners (Intel Xeon server CPUs) may show different results due to lower single-thread performance. For stable benchmarks, run locally with uv run python benchmarks/bench_serialization.py.

dumps

Benchmark                           json+DJE    blitzjson    Speedup
------------------------------------------------------------------------
Simple dict (4 fields)                 2.5µs        0.8µs      3.0x
Nested dict (deep)                     5.4µs        1.8µs      3.0x
Large list (1000 items)              752.1µs      193.2µs      3.9x
String-heavy dict (20 keys)            4.8µs        1.5µs      3.1x
Datetime dict                         10.3µs        3.6µs      2.8x
UUID dict                              7.3µs        3.9µs      1.9x
Decimal dict                           4.4µs        1.6µs      2.7x
Mixed dict (all types)                 7.3µs        2.8µs      2.6x

loads

Benchmark                               json    blitzjson    Speedup
------------------------------------------------------------------------
Simple dict (4 fields)                 1.5µs        0.8µs      2.0x
Nested dict (deep)                     5.1µs        3.2µs      1.6x
Large list (1000 items)              716.0µs      421.2µs      1.7x
String-heavy dict (20 keys)            4.3µs        2.7µs      1.6x

Django Response

Benchmark                             JsonResponse      BlitzJson    Speedup
------------------------------------------------------------------------
API response (50 users)                 44.9µs         19.6µs      2.3x

Requirements

Python 3.10+
No Rust installation required (pre-built wheels)

License

MIT - Ricardo Robles Fernández

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

blitzjson-0.1.0.tar.gz (39.7 kB view details)

Uploaded Aug 25, 2026 Source

Built Distributions

If you're not sure about the file name format, learn more about wheel file names.

The dropdown lists show the available interpreters, ABIs, and platforms. Enable javascript to be able to filter the list of wheel files.

blitzjson-0.1.0-cp310-abi3-win_amd64.whl (190.8 kB view details)

Uploaded Aug 25, 2026 CPython 3.10+Windows x86-64

blitzjson-0.1.0-cp310-abi3-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (277.7 kB view details)

Uploaded Aug 25, 2026 CPython 3.10+manylinux: glibc 2.17+ x86-64

blitzjson-0.1.0-cp310-abi3-macosx_11_0_arm64.whl (259.9 kB view details)

Uploaded Aug 25, 2026 CPython 3.10+macOS 11.0+ ARM64

File details

Details for the file blitzjson-0.1.0.tar.gz.

File metadata

Download URL: blitzjson-0.1.0.tar.gz
Upload date: Aug 25, 2026
Size: 39.7 kB
Tags: Source
Uploaded using Trusted Publishing? Yes
Uploaded via: twine/7.0.0 CPython/3.13.14

File hashes

Hashes for blitzjson-0.1.0.tar.gz
Algorithm	Hash digest
SHA256	`593997d806ad39ca5e36ea4415df850b12743ab05a437f9975ea4b336d5d6964`
MD5	`eb088f77f49e08b20f26f50e9e81fb6d`
BLAKE2b-256	`eebf3cd7b70d8c1c55cbb8d5c208ed29f45763b99b9caa2c4377b8264e8e271f`

See more details on using hashes here.

Provenance

The following attestation bundles were made for blitzjson-0.1.0.tar.gz:

Publisher: build.yml on rroblf01/blitzjson

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

Statement:
- Statement type: https://in-toto.io/Statement/v1
- Predicate type: https://docs.pypi.org/attestations/publish/v1
- Subject name: blitzjson-0.1.0.tar.gz
- Subject digest: 593997d806ad39ca5e36ea4415df850b12743ab05a437f9975ea4b336d5d6964
- Sigstore transparency entry: 2585874517
- Sigstore integration time: Aug 25, 2026
Source repository:
- Permalink: rroblf01/blitzjson@bc35495f581c5372a547ff3a7d58102db0a510bd
- Branch / Tag: refs/tags/v0.1.0
- Owner: https://github.com/rroblf01
- Access: public
Publication detail:
- Token Issuer: https://token.actions.githubusercontent.com
- Runner Environment: github-hosted
- Publication workflow: build.yml@bc35495f581c5372a547ff3a7d58102db0a510bd
- Trigger Event: release

File details

Details for the file blitzjson-0.1.0-cp310-abi3-win_amd64.whl.

File metadata

Download URL: blitzjson-0.1.0-cp310-abi3-win_amd64.whl
Upload date: Aug 25, 2026
Size: 190.8 kB
Tags: CPython 3.10+, Windows x86-64
Uploaded using Trusted Publishing? Yes
Uploaded via: twine/7.0.0 CPython/3.13.14

File hashes

Hashes for blitzjson-0.1.0-cp310-abi3-win_amd64.whl
Algorithm	Hash digest
SHA256	`5af218fadc4385ae5ec8eb20e63eeb320f51cccc85799d75e3140033931cfbb0`
MD5	`05261fdd8dab1531fac54968541db5b5`
BLAKE2b-256	`712389ac67ed3686c0343cce83df440ee8baefc200749363cb37f3880d368a5a`

See more details on using hashes here.

Provenance

The following attestation bundles were made for blitzjson-0.1.0-cp310-abi3-win_amd64.whl:

Publisher: build.yml on rroblf01/blitzjson

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

Statement:
- Statement type: https://in-toto.io/Statement/v1
- Predicate type: https://docs.pypi.org/attestations/publish/v1
- Subject name: blitzjson-0.1.0-cp310-abi3-win_amd64.whl
- Subject digest: 5af218fadc4385ae5ec8eb20e63eeb320f51cccc85799d75e3140033931cfbb0
- Sigstore transparency entry: 2585874778
- Sigstore integration time: Aug 25, 2026
Source repository:
- Permalink: rroblf01/blitzjson@bc35495f581c5372a547ff3a7d58102db0a510bd
- Branch / Tag: refs/tags/v0.1.0
- Owner: https://github.com/rroblf01
- Access: public
Publication detail:
- Token Issuer: https://token.actions.githubusercontent.com
- Runner Environment: github-hosted
- Publication workflow: build.yml@bc35495f581c5372a547ff3a7d58102db0a510bd
- Trigger Event: release

File details

Details for the file blitzjson-0.1.0-cp310-abi3-manylinux_2_17_x86_64.manylinux2014_x86_64.whl.

File metadata

Download URL: blitzjson-0.1.0-cp310-abi3-manylinux_2_17_x86_64.manylinux2014_x86_64.whl
Upload date: Aug 25, 2026
Size: 277.7 kB
Tags: CPython 3.10+, manylinux: glibc 2.17+ x86-64
Uploaded using Trusted Publishing? Yes
Uploaded via: twine/7.0.0 CPython/3.13.14

File hashes

Hashes for blitzjson-0.1.0-cp310-abi3-manylinux_2_17_x86_64.manylinux2014_x86_64.whl
Algorithm	Hash digest
SHA256	`ff8a43694a406694c6dcf8ac943dbfd8aedc95fb76f1154529c21c205f10e418`
MD5	`0d575756463cfe001a9b6ecd5b5b489a`
BLAKE2b-256	`67fc5c6094c6c97eb09bb20858fda7a16a3492ed79aaddfacc86fba58f864d82`

See more details on using hashes here.

Provenance

The following attestation bundles were made for blitzjson-0.1.0-cp310-abi3-manylinux_2_17_x86_64.manylinux2014_x86_64.whl:

Publisher: build.yml on rroblf01/blitzjson

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

Statement:
- Statement type: https://in-toto.io/Statement/v1
- Predicate type: https://docs.pypi.org/attestations/publish/v1
- Subject name: blitzjson-0.1.0-cp310-abi3-manylinux_2_17_x86_64.manylinux2014_x86_64.whl
- Subject digest: ff8a43694a406694c6dcf8ac943dbfd8aedc95fb76f1154529c21c205f10e418
- Sigstore transparency entry: 2585874598
- Sigstore integration time: Aug 25, 2026
Source repository:
- Permalink: rroblf01/blitzjson@bc35495f581c5372a547ff3a7d58102db0a510bd
- Branch / Tag: refs/tags/v0.1.0
- Owner: https://github.com/rroblf01
- Access: public
Publication detail:
- Token Issuer: https://token.actions.githubusercontent.com
- Runner Environment: github-hosted
- Publication workflow: build.yml@bc35495f581c5372a547ff3a7d58102db0a510bd
- Trigger Event: release

File details

Details for the file blitzjson-0.1.0-cp310-abi3-macosx_11_0_arm64.whl.

File metadata

Download URL: blitzjson-0.1.0-cp310-abi3-macosx_11_0_arm64.whl
Upload date: Aug 25, 2026
Size: 259.9 kB
Tags: CPython 3.10+, macOS 11.0+ ARM64
Uploaded using Trusted Publishing? Yes
Uploaded via: twine/7.0.0 CPython/3.13.14

File hashes

Hashes for blitzjson-0.1.0-cp310-abi3-macosx_11_0_arm64.whl
Algorithm	Hash digest
SHA256	`aa3b3d766905987f55c073d68b4ade59ea55b85d2a0f72880262c5727d704972`
MD5	`0cdbe4fd3358130325cf68dcf6de58c3`
BLAKE2b-256	`23eeb97d3014a335cd6ac9b0d04f031ae7ba8df886e1de6125092b67256f4ec6`

See more details on using hashes here.

Provenance

The following attestation bundles were made for blitzjson-0.1.0-cp310-abi3-macosx_11_0_arm64.whl:

Publisher: build.yml on rroblf01/blitzjson

Attestations: Values shown here reflect the state when the release was signed and may no longer be current.

Statement:
- Statement type: https://in-toto.io/Statement/v1
- Predicate type: https://docs.pypi.org/attestations/publish/v1
- Subject name: blitzjson-0.1.0-cp310-abi3-macosx_11_0_arm64.whl
- Subject digest: aa3b3d766905987f55c073d68b4ade59ea55b85d2a0f72880262c5727d704972
- Sigstore transparency entry: 2585874890
- Sigstore integration time: Aug 25, 2026
Source repository:
- Permalink: rroblf01/blitzjson@bc35495f581c5372a547ff3a7d58102db0a510bd
- Branch / Tag: refs/tags/v0.1.0
- Owner: https://github.com/rroblf01
- Access: public
Publication detail:
- Token Issuer: https://token.actions.githubusercontent.com
- Runner Environment: github-hosted
- Publication workflow: build.yml@bc35495f581c5372a547ff3a7d58102db0a510bd
- Trigger Event: release

Release history Release notifications | RSS feed

This release

0.1.0 This release

Aug 25, 2026 4 files

blitzjson 0.1.0

blitzjson

Features

Installation

Quick Start

Monkey-patching (try before you commit)

Supported Types

Django-Specific

API

dumps(obj, **kwargs)

loads(s, **kwargs)

dump(obj, fp, **kwargs) / load(fp, **kwargs)

dumpb(obj, pretty=False)

dump_queryset(queryset) / dump_queryset_bytes(queryset)

Benchmarks

dumps

loads

Django Response

Requirements

License

Project links

Key dates

1 maintainer

Credits

GitHub Statistics

License expression

Requires

Provides Extra

Classifiers

Download files

Source Distribution

Built Distributions

File details

File metadata

File hashes

Provenance

File details

File metadata

File hashes

Provenance

File details

File metadata

File hashes

Provenance

File details

File metadata

File hashes

Provenance

Release history Release notifications | RSS feed

`dumps(obj, **kwargs)`

`loads(s, **kwargs)`

`dump(obj, fp, kwargs)` / `load(fp, kwargs)`

`dumpb(obj, pretty=False)`

`dump_queryset(queryset)` / `dump_queryset_bytes(queryset)`