x402 support

[Gallaecio]

Note: There is a slight behavior change: it used to be that an empty API key defined as an environment variable was taken into account; that is no longer the case.

[Gallaecio]

@kmike @wRAR Ready for review, but marked as a draft to prevent merging before the feature is available in Zyte API.

[hk2281]

@Gallaecio @wRAR hi can ask about this feature, zyte api support it? Or is beta flow? Сuz i'm tryed used client with my eth private key and get response like this

zyte_api._errors.RequestError: RequestError: 401, message=Unauthorized, headers=<CIMultiDictProxy('Date': 'Thu, 02 Jul 2026 06:54:11 GMT', 'Content-Type': 'application/problem+json', 'Content-Length': '202', 'Connection': 'close', 'WWW-Authenticate': 'Basic realm="Zyte API"', 'Request-Id': 'cfaa93a1f5391b0b3b3ac48e769cd9d5', 'Vary': 'Accept-Encoding', 'Strict-Transport-Security': 'max-age=31536000; includeSubDomains; preload', 'Access-Control-Allow-Credentials': 'true', 'Access-Control-Expose-Headers': '*, X-Project-Key', 'Access-Control-Allow-Methods': 'GET, PUT, POST, DELETE, PATCH, OPTIONS', 'Access-Control-Allow-Headers': 'DNT, Keep-Alive, User-Agent, X-Requested-With, If-Modified-Since, Cache-Control, Content-Type, Range, Authorization, X-Project-Key', 'Access-Control-Max-Age': '1728000')>, body=b'{"type":"/auth/not-valid","title":"Authentication Info Invalid","status":401,"detail":"No valid authentication info found in the request. Check the documentation for the correct authentication schema."}', request_id=cfaa93a1f5391b0b3b3ac48e769cd9d5

my env setup

Python 3.12.9

Package              Version         Editable project location
-------------------- --------------- -------------------------------------------------
aiohappyeyeballs     2.7.1
aiohttp              3.14.1
aiosignal            1.4.0
annotated-doc        0.0.4
annotated-types      0.7.0
anyio                4.14.1
attrs                26.1.0
bitarray             3.8.2
blinker              1.9.0
brotli               1.2.0
certifi              2026.6.17
charset-normalizer   3.4.7
ckzg                 2.1.7
click                8.4.2
cytoolz              1.1.0
detect-installer     0.1.0
dnspython            2.8.0
email-validator      2.3.0
eth-abi              5.2.0
eth-account          0.13.7
eth-hash             0.8.0
eth-keyfile          0.8.1
eth-keys             0.7.0
eth-rlp              2.2.0
eth-typing           6.0.0
eth-utils            6.0.0
fastapi              0.139.0
fastapi-cli          0.0.27
fastapi-cloud-cli    0.22.1
fastar               0.11.0
flask                3.1.3
frozenlist           1.8.0
h11                  0.16.0
hexbytes             1.3.1
httpcore             1.0.9
httptools            0.8.0
httpx                0.28.1
idna                 3.18
itsdangerous         2.2.0
jinja2               3.1.6
markdown-it-py       4.2.0
markupsafe           3.0.3
mdurl                0.1.2
multidict            6.7.1
parsimonious         0.10.0
propcache            0.5.2
pycryptodome         3.23.0
pydantic             2.13.4
pydantic-core        2.46.4
pydantic-extra-types 2.11.1
pydantic-settings    2.14.2
pygments             2.20.0
python-dotenv        1.2.2
python-multipart     0.0.32
pyunormalize         17.0.0
pyyaml               6.0.3
regex                2026.6.28
requests             2.34.2
rich                 15.0.0
rich-toolkit         0.20.1
rignore              0.7.6
rlp                  4.1.0
runstats             2.0.0
sentry-sdk           2.64.0
shellingham          1.5.4
starlette            1.3.1
tenacity             9.1.4
toolz                1.1.0
tqdm                 4.68.3
typer                0.26.8
types-requests       2.33.0.20260518
typing-extensions    4.15.0
typing-inspection    0.4.2
urllib3              2.7.0
uvicorn              0.49.0
uvloop               0.22.1
w3lib                2.4.1
watchfiles           1.2.0
web3                 7.16.0
websockets           15.0.1
werkzeug             3.1.8
x402                 1.0.0
yarl                 1.24.2
zyte-api             0.10.0