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Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →FRED documents different request thresholds for its two API versions: v1 allows up to 120 requests per minute, while v2 allows up to 2 requests per second before returning HTTP 429. Treat these as version-specific thresholds, not a guaranteed sustained throughput. FRED warns that ignoring throttling can result in a temporary block. To handle limits safely, identify the endpoint version, pace requests locally below its threshold, and use bounded retries with backoff and jitter after a 429.
FRED API request limits by version
FRED’s current error documentation lists separate thresholds for v1 and v2. The units differ, so select the limit that matches the endpoint your application calls rather than treating the figures as interchangeable.
| API version | Documented threshold before HTTP 429 | Authentication | Retrieval model |
|---|---|---|---|
| v1 | Up to 120 requests per minute, according to FRED’s v1 Errors documentation. | Registered API key in the api_key request variable; see FRED’s API key documentation. |
Customizable, incremental, series-level retrieval from FRED and ALFRED, as described in the FRED API overview. |
| v2 | Up to 2 requests per second, according to FRED’s v2 Errors documentation. | Bearer token in the HTTP Authorization header; see FRED’s v2 API key documentation. |
Designed for bulk observation retrieval across a release and full histories, as described in the FRED API overview. |
The documentation pages do not show a publication or revision date. The figures above are the thresholds stated on FRED’s current version-specific pages, accessed in 2026; FRED’s terms of use reserve the right to set or adjust transaction and bandwidth limits. Do not assume either threshold guarantees a particular sustained throughput for every workload.
What a FRED API 429 error means
HTTP 429 is FRED’s documented signal that a request threshold has been exceeded. FRED’s v1 and v2 error pages both warn: “Not complying with the throttling can result in a temporary block.” The documentation does not state an exact block duration or promise a particular unblock time.
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A 429 is not the only error worth checking. FRED says errors use standard HTTP status codes and include an XML or JSON response body. The documented status sets differ by version:
- v1: 400 Bad Request, 404 Not Found, 423 Locked, 429 Too Many Requests, and 500 Internal Server Error, per the v1 Errors page.
- v2: 400 Bad Request, 401 Missing or invalid credentials, 404 Not Found, 406 Invalid format, 429 Too Many Requests, and 500 Internal Server Error, per the v2 Errors page.
Read the response status and body before deciding whether to retry. A malformed parameter, invalid credential, locked resource, or invalid format needs a correction—not repeated requests at the same pace.
How to pace FRED API requests
- Identify the version. Check the URL and endpoint your program calls. Keep separate request limits for v1 and v2 because FRED documents their thresholds in different units.
- Use a per-application queue or limiter. Pace outgoing requests below the relevant published threshold. Leave headroom for concurrent workers and bursts; that buffer is prudent client design, not a FRED-specified safety margin.
- Count every request. Include retries and pagination calls in the same limiter. For large v2 release-observation pulls, the endpoint can return a
next_cursorwhen the observation limit is exceeded; following that cursor requires additional requests. See the v2 release observations documentation. - Log useful diagnostics. Record the endpoint version, status code, and error message. Parse the response format actually returned, and redact API keys and other credentials from logs.
How to handle a 429 response
FRED documents the threshold and warns of temporary blocking, but it does not prescribe a client retry algorithm or publish exact retry intervals on the cited error pages. A practical client-side approach is bounded exponential backoff with jitter; this is engineering guidance, not a FRED requirement or a tested FRED recipe.
- Pause requests to the affected endpoint instead of immediately resending the same batch at its previous pace.
- Retry after a backoff delay that increases between attempts, with random jitter to prevent many workers from retrying simultaneously.
- Set a retry cap and surface a persistent failure to the application rather than retrying indefinitely.
- After a successful response, continue through the local limiter rather than releasing a queued burst all at once.
Do not assume that FRED returns a Retry-After header or that a specific wait will restore access; the cited documentation does not establish either behavior.
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Check credentials and request errors before retrying
Authentication placement depends on the API version. A key sent in the wrong place can cause an error that will not be fixed by waiting.
For v1
Use a registered 32-character lowercase alphanumeric API key in the api_key request variable. FRED’s API key instructions describe registration and key use; its terms say requests with an invalid key are blocked.
For v2
Send the key in the HTTP Authorization: Bearer … header. FRED’s v2 key instructions recommend a distinct key for each application and say each application user should use their own key.
Keep keys out of published examples, client-visible logs, and source repositories. The sample key shown in FRED documentation is demonstrative; use a registered key. If the response is not 429, inspect its status and body and correct the associated request, credential, or format issue before trying again.
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When the documented threshold is not enough
If a legitimate workload requires a higher request rate, FRED’s version-specific error pages say to contact it. They do not guarantee that a higher limit will be approved. Do not try to evade throttling: FRED’s terms prohibit unreasonable bandwidth use and use that adversely affects service stability or other applications.
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