noresponse

The NoResponse client for Python. It assesses a signup or gateway event, polls a pending assessment, pages through an account's history, records what you later learned, rotates your API key and verifies webhooks.

Python 3.10 or later. Sync and asyncio. Fully typed (py.typed). The client is generated from the NoResponse OpenAPI document; the thin layer on top of it (defaults, response types, errors, wait, webhooks) is hand-written.

pip install noresponse

Quick start

from noresponse import NoResponse

nr = NoResponse()  # reads NORESPONSE_API_KEY

assessment = nr.assessments.create(
    account_id="usr_8f2k1",
    identifiers={"email": "jordan.lee@example.com", "name": "Jordan Lee", "ip": "81.2.69.160"},
)

if assessment.status == "pending":
    # No recommendation yet. Apply your fallback now, then wait or take the webhook.
    assessment = nr.assessments.wait(assessment.assessment_id)

if assessment.risk is not None:
    print(assessment.risk.recommendation)  # allow, step_up or review

Keep the API key on your server. The client raises ValueError at construction without one.

Async code uses the same client with the _async methods:

async with NoResponse() as nr:
    assessment = await nr.assessments.create_async(
        account_id="usr_8f2k1",
        identifiers={"email": "jordan.lee@example.com"},
    )

Configuration

import httpx
from noresponse import NoResponse

nr = NoResponse(
    "nrk_...",                                   # default: NORESPONSE_API_KEY
    server_url="https://api.noresponse.org",     # default; or NORESPONSE_BASE_URL
    timeout_ms=10_000,                           # per request
    retry_config=None,                           # None turns retries off
    client=httpx.Client(proxy="http://proxy:3128"),
)

Use the client as a context manager (with or async with) to close the HTTP clients it opened. Make one client per process and reuse it.

Every method also takes server_url, timeout_ms and http_headers for that call, and every method except keys.rotate takes retries. Rotation is not idempotent, so it is never retried.

Assessments

Create

assessment = nr.assessments.create(
    account_id="usr_8f2k1",                                    # your opaque account id
    identifiers={"email": "jordan.lee@example.com"},           # email, username or phone; name and ip refine the match
    policy_context={"flow": "signup", "region": "AU"},         # signup, login, recovery or profile_change
    client_context={"timezone": "Australia/Sydney", "platform": "web", "form_duration_ms": 1800},
    auth_context=auth_context,                                 # a verified session, see below
    response_mode="standard",                                  # detailed adds signals and risk.details (detailed scope)
    idempotency_key="signup-usr_8f2k1-0001",
)

The answer is the assessment whether the API answered 200 (complete or partial) or 202 (pending). status is complete, partial or pending; risk.recommendation is allow, step_up or review and is absent while pending.

The idempotency key is generated (a UUID) when you leave it out and is sent again on every retry of that call. Pass your own to make a retry of the same signup from your side replay the same assessment: the API answers the latest version with meta.idempotent_replayed true and starts no new work. The same key with a different body answers 409.

Get and wait

latest = nr.assessments.get(assessment.assessment_id)
settled = nr.assessments.wait(assessment.assessment_id, timeout=30)

wait polls get until the status is no longer pending, sleeping the server's Retry-After (at least one second) between polls, and raises APITimeoutError after timeout seconds (default 30). The error is a WaitTimeoutError whose last attribute is the final pending assessment. Pass response_mode="detailed" to either. In async code use get_async and wait_async.

Query an account's history

page = nr.assessments.query(account_id="usr_8f2k1", limit=20)
page.items       # newest first, each at its latest version
page.has_more    # True when another page exists
page.next_page() # the next page, or None

for assessment in page:
    ...  # every assessment across every page

In async code, page = await nr.assessments.query_async(...), then async for assessment in page and await page.next_page_async().

Record an outcome

receipt = nr.assessments.record_outcome(
    assessment.assessment_id,
    outcome="chargeback",  # confirmed_abuse, account_takeover, chargeback, false_positive, legitimate or unknown
    observed_at="2026-10-20T10:00:00Z",
    external_ref="case-42",
)

Outcomes take an idempotency_key the same way create does.

Keys

rotation = nr.keys.rotate(overlap_seconds=3600)
rotation.key                      # the new key, shown once
rotation.previous_key_expires_at  # when the key that signed the request stops working

The default overlap is 24 hours (minimum 60 seconds, maximum 7 days). Rotate with the new key next time.

Response metadata

Every returned object carries meta, which is not part of the body and is left out of model_dump():

assessment.meta.request_id           # X-Request-ID, to quote when you contact us
assessment.meta.retry_after          # seconds, when the API sent Retry-After
assessment.meta.location             # the polling path of a pending assessment
assessment.meta.idempotent_replayed  # True when the answer replays an earlier request

Assessments that arrive by webhook or inside a page have an empty meta.

Errors

Every API error extends NoResponseError and has the same attributes whatever the status: status, type, title, detail, code, request_id, retry_after and, on a 400, invalid_params (the offending fields). str(error) reads HTTP 429 rate_limited: Rate limited. The tenant's assessment rate is exhausted; retry after the Retry-After interval. (request 0123456789abcdef0123456789abcdef). The raw status_code, headers, body and raw_response are there too.

from noresponse import NoResponseError, RateLimitError, APIConnectionError

try:
    nr.assessments.create(account_id="usr_8f2k1", identifiers={"email": email})
except RateLimitError as error:
    schedule(error.retry_after)
except APIConnectionError:  # includes APITimeoutError
    fallback()
except NoResponseError as error:
    log(error.status, error.code, error.request_id)

The two transport errors do not extend NoResponseError, because no response exists to describe.

Retries

Connection errors, 408, 429 and every 5xx are retried with exponential backoff (500 ms, doubling to 8 s between attempts) for at most 30 s in all. When the API sends Retry-After, the client sleeps that long instead. A POST sends the same Idempotency-Key on every attempt, so a retried create or outcome is recorded once. 409 and other 4xx are not retried.

Override per client with retry_config, or per call with retries:

from noresponse.utils import BackoffStrategy, RetryConfig

nr.assessments.create(
    account_id="usr_8f2k1",
    identifiers={"email": email},
    retries=RetryConfig("backoff", BackoffStrategy(200, 2000, 2, 10_000), True),
)
nr.assessments.create(account_id="usr_8f2k1", identifiers={"email": email}, retries=None)  # no retries

Webhooks

Verify the exact bytes you received, then act on the typed event. secrets maps each whk_ key id we give you to its secret; hold both during a rotation.

import os
from noresponse import Webhook, WebhookVerificationError
from noresponse import AssessmentExpired, Assessment

SECRETS = {
    os.environ["NORESPONSE_WEBHOOK_KEY_ID"]: os.environ["NORESPONSE_WEBHOOK_SECRET"],
    # During a rotation, add the previous key id and secret here as well.
}

@app.post("/webhooks/noresponse")  # FastAPI: await request.body() is the raw body
async def handler(request: Request) -> Response:
    try:
        event = Webhook.construct_event(await request.body(), request.headers, SECRETS)
    except WebhookVerificationError:
        return Response(status_code=400)
    if event.type == "endpoint.verification":
        return JSONResponse(Webhook.verification_response(event))
    if isinstance(event.data, AssessmentExpired):
        forget(event.data.assessment_id)  # GET now answers 404
    elif isinstance(event.data, Assessment) and is_newer(event.data):  # keep the highest assessment_version per assessment
        apply(event.data)  # the full assessment, as assessments.get returns it
    return Response(status_code=204)

construct_event(payload, headers, secrets, tolerance_seconds=300) takes the raw body (bytes or the exact text) and any header mapping or list of pairs, and refuses a repeated signature header, a delivery older than 300 seconds, an unknown key id or a bad signature with a WebhookVerificationError whose code says which. Deliveries are at least once: deduplicate on event.id. The same functions are on Webhook, on nr.webhooks and in the noresponse namespace.

Logging

Set NORESPONSE_LOG=debug, or pass debug_logger, to get one line per request and response: method, URL, status and request id. The API key, other headers and bodies are kept out of the log.

Raw responses

nr.assessments.with_raw_response.get(...) returns an object with status_code, headers, request_id and http_response. Its parse() returns the generated envelope, whose result is the model. Use it when you need the status line or every header.

Support

Documentation: https://docs.noresponse.org. Issues: https://github.com/noresponsehq/python/issues. Quote meta.request_id or error.request_id when you write to us.

Apache-2.0.