CaptureKit documents rate limits as HTTP 401 responses with an explanatory error message, and recommends waiting 2–5 seconds before retrying. Its Capture endpoint reference also lists HTTP 429, however, so check both the status and response body rather than assuming every limit arrives as 429. Retry transient 500 errors and network timeouts with bounded exponential backoff; do not retry a 402 payment failure until the billing issue is fixed.
How to recognize a CaptureKit rate limit
CaptureKit’s general error-handling guide says subscription rate limits and API-key quota limits return HTTP 401. Read the error text to distinguish throttling from an invalid, inactive, or expired API key. A quota message may identify a daily, total, weekly, or monthly limit.
There is a documentation inconsistency: the Capture endpoint reference lists a 429 response schema, while the general error guide says rate limits return 401, not 429. The reviewed documentation does not explain whether 429 is used in some circumstances or whether that endpoint schema is outdated. Handle the status and body you actually receive; do not make 429 your only rate-limit check. Capture endpoint reference · Error-handling guide
The endpoint authenticates with an x-api-key header and deducts one credit per successful capture call. CaptureKit’s getting-started page says credits are deducted only when the call succeeds. Getting started
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Which failures are safe to retry?
| Response or failure | Recommended action |
|---|---|
| 401 with a rate-limit or quota message | Wait 2–5 seconds, then retry within a bounded policy. If the message instead indicates invalid, inactive, or expired credentials, fix the key rather than retrying. |
| 429 | The endpoint reference lists this status, but the general guide describes rate limits as 401. Inspect the response body and handle it as a limit only when the response indicates throttling. |
| 402 payment required | Stop retries. Add credits, enable Auto Top-Up, upgrade, or settle an unpaid invoice as appropriate, then submit again. CaptureKit says a payment-required request is not executed or billed. |
| 500 | Retry as a transient failure using exponential backoff, with no more than three attempts in the documented guidance. |
| Network timeout | Retry with bounded exponential backoff. A timeout does not prove the server did not receive the request, so avoid uncontrolled duplicate submissions. |
| 400, 403, or 404 | Correct invalid parameters, check permissions, or handle the missing resource. These are not generic retry conditions. |
These status recommendations follow CaptureKit’s error guide and best-practices guide. The guide’s retry example is illustrative, not a provider-enforced service guarantee.
Implement bounded retries
Make CaptureKit calls from a backend or trusted automation environment so the API key is not exposed in browser-side code. Check the HTTP status before treating the response as a successful capture. For 401, parse the error text; retry only if it identifies a rate limit.
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import time
import requests
API_URL = "https://api.capturekit.dev/v1/capture"
API_KEY = "YOUR_API_KEY"
def capture(payload, max_retries=3):
# max_retries counts retries after the initial request.
for attempt in range(max_retries + 1):
try:
response = requests.post(
API_URL,
headers={"x-api-key": API_KEY},
json=payload,
timeout=65,
)
except requests.Timeout:
if attempt == max_retries:
raise
time.sleep(0.5 * (2 ** attempt))
continue
if response.status_code == 401:
message = response.text.lower()
if "rate limit" in message or "quota" in message:
if attempt == max_retries:
response.raise_for_status()
time.sleep(2) # CaptureKit recommends 2–5 seconds.
continue
response.raise_for_status() # Fix credentials; do not repeat blindly.
if response.status_code == 429:
message = response.text.lower()
if "rate limit" not in message and "quota" not in message:
response.raise_for_status()
if attempt == max_retries:
response.raise_for_status()
time.sleep(2)
continue
if response.status_code == 500:
if attempt == max_retries:
response.raise_for_status()
time.sleep(0.5 * (2 ** attempt))
continue
# Includes 402 and non-retryable 400/403/404 responses.
response.raise_for_status()
return response
raise RuntimeError("CaptureKit retry loop ended unexpectedly")
result = capture({"url": "https://example.com"})
print(result.status_code, result.headers.get("content-type"))Replace the URL and request payload with the fields required for your capture. The sample caps retries after three retries (four total attempts including the first); CaptureKit’s documented maximum of three attempts should instead be enforced as a total-attempt cap if you want to follow that guidance literally. For production, choose one consistent cap, add random jitter to delay concurrent clients from retrying together, and log the status and error body while redacting credentials.
Why the delay differs by failure
For a rate-limit 401, the provider’s specific guidance is a 2–5 second wait. For 500 and network timeouts, its best-practices example starts at 500 milliseconds and doubles each delay: 500 ms, 1 second, then 2 seconds. That sample accepts a configurable maximum retry count; it is not a promise that a request will succeed after those attempts. CaptureKit best practices
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Manage quotas, keys, and batches
CaptureKit describes two related constraints: subscription rate limits and API-key quotas. The error message can identify the type of limit and, for a key quota, its period. The reviewed documentation does not publish a specific requests-per-second limit, concurrency cap, or burst threshold, so do not derive one from a sample delay.
Limits and quota are workspace-wide and shared across API keys. Creating extra keys does not create separate capacity. Spread batch requests over time, monitor usage, and adjust pacing to your plan; CaptureKit’s guide illustrates a configurable 100 ms delay but does not guarantee that this spacing stays below every plan’s limit.
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If limits recur, consider a higher plan or ask CaptureKit support about capacity. The plans page lists Free trial at $0/month for 100 credits/month, Starter at $7/month for 1,000 credits/month, Pro at $29/month for 10,000 credits/month, and Ultimate at $89/month for 50,000 credits/month. These are published plan details, which may change; verify current prices and allowances on the CaptureKit plans page before purchasing. Quota documentation
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Account for CaptureKit’s timeout
CaptureKit documents a 60-second hard server-side timeout for real-time calls. A client timeout can end the wait sooner, as in the 65-second example above, but increasing the client timeout cannot extend the server limit. Use async mode for work that may take longer. Long-running requests and async mode
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Troubleshoot common retry problems
- 401 repeats after the delay: Check the error field. If it names invalid, inactive, or expired credentials, replace or reactivate the key. If it names a subscription or key quota, wait, reduce request frequency, or review workspace usage.
- More keys do not relieve throttling: Quota and rate limits are shared workspace-wide. Reduce aggregate traffic or discuss a higher allowance rather than distributing requests across keys.
- 402 persists: Resolve the balance, credits, Auto Top-Up, plan, or unpaid-invoice issue first. Immediate retries cannot fix a billing block.
- 500 or timeout repeats: Keep retries bounded, use backoff, and inspect whether the operation should run asynchronously because of the 60-second server-side limit.
- 429 handling is inconsistent: CaptureKit’s endpoint reference shows a 429 schema but its general guide identifies rate limits as 401. Record the actual response status and body; do not treat every 401 as throttling or every 429 as a confirmed quota event without checking its message.
- Batch traffic triggers limits: Slow the aggregate request stream and monitor workspace usage. The documented 100 ms example is configurable guidance, not a guaranteed safe rate.
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Frequently Asked Questions
Does CaptureKit charge credits for a rate-limited request?
The Capture endpoint reference says one credit is charged per successful capture call, and CaptureKit’s getting-started page says credits are deducted only when a call succeeds.
Can another API key give my workspace more rate-limit capacity?
No. CaptureKit says quota and rate limits are workspace-wide and shared across its API keys.
Quick Recap
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