Does this API call my service or replay requests?

No. You send a JSON description of an error event (status, optional headers, duration, etc.). Nothing is executed against your URLs.

What is the maximum request body size?

1MB per request for both POST /analyze and POST /analyze/batch.

Does it store or log my payloads?

Processing is stateless; the service does not persist your request bodies for this product.

Is this AI or machine learning?

No. Classification uses deterministic rules grounded in HTTP semantics and common proxy or gateway header patterns.

What status codes are supported?

statusCode must be a number from 400 through 599. Values outside that range return INVALID_STATUS_CODE or validation errors in batch.

What is the difference between /analyze and /analyze/batch?

/analyze accepts one error object. /analyze/batch accepts a non-empty JSON array of events and returns results plus a summary with category counts.

Where are pricing and quotas defined?

On RapidAPI: Basic is free with 100 requests per month; Pro is $9.99/month with 10,000; Ultra is $49.99/month (popular) with 100,000; Mega is $99.99/month with 250,000. Overage is on the live listing.

What is the minimum input for a useful result?

Only statusCode is required. Adding duration, responseHeaders, proxyType, and retryAttemptCount usually improves confidence and next steps.

Classify 4xx/5xx Failures: Root Trigger, Layer, and Next Steps

Send one error event to POST /analyze or many to POST /analyze/batch with statusCode (400–599) plus optional method, url, duration, requestHeaders, responseHeaders, proxyType, retryAttemptCount, and more. Get triggerCategory, triggerSubcategory, confidenceScore, likelyLayer, recommendedNextSteps, retryRecommendation, and severityHint—rule-based, deterministic, not ML. No calls to your URLs. 1MB JSON limit.

Try the Analyzer Basic on RapidAPI: 100 requests/month free

Turn “another 502” into a routing decision. Same status code can mean upstream refusal, gateway timeout, or misconfigured proxy. Headers plus timing give the model enough signal to suggest infra vs app vs client follow-up—without log scraping.

Real-world use cases

On-call triage — Attach analysis to PagerDuty or Slack when spikes hit.
Alert enrichment — Add triggerCategory and likelyLayer before routing to teams.
Client integration debug — Outbound 401/403 with request header context.
429 investigation — Combine Retry-After and retryAttemptCount for storm vs legitimate limit.
Batch pattern mining — /analyze/batch + summary.categoryCounts for weekly reviews.

Why not maintain this logic in every service?

Proxy-specific headers and RFC nuance change over time
Duplicated heuristics drift between teams
Central rules stay testable and consistent

Who this API helps

Backend and platform engineers
SRE and incident response
API and developer-relations teams
Observability pipeline owners

What the API does

POST /analyze — JSON object: required numeric statusCode in 400–599; optional fields per schema below.

POST /analyze/batch — JSON array of the same event objects (non-empty). Response includes results and summary with categoryCounts.

GET /health — { "status": "ok" }.

This is not a substitute for traces or logs; it classifies HTTP-level signals you already captured.

Deterministic by design

Identical JSON in yields identical JSON out—suitable for fixtures and contract tests.

Request & response

Host: api-fault-analysis-engine.p.rapidapi.com — confirm x-rapidapi-host in your RapidAPI app.

View event fields · View analysis response · View batch response · View HTTP errors

Required: statusCode (number, 400–599).

Field	Description
`method`	HTTP method string.
`url` / `path`	Request URL or path.
`timestamp`	String or number.
`duration`	Round-trip ms.
`direction`	e.g. incoming, outgoing, upstream.
`requestHeaders` / `responseHeaders`	Flat maps (string or string[] values).
`proxyType`	e.g. envoy, nginx, cloudflare, cloudfront.
`timeoutValues`	`client`, `gateway`, `upstream` (ms).
`payloadSize`	`request` / `response` bytes.
`retryAttemptCount`	Integer retry count.
`tlsMetadata`	Protocol, cipher, certificateError.
`errorMessage`	Short message or log excerpt.

Field	Description
`triggerCategory`	High-level bucket (e.g. TIMEOUT, DEPENDENCY_FAILURE).
`triggerSubcategory`	Fine-grained label.
`confidenceScore`	0–1.
`classificationReasoning`	Human-readable rationale.
`likelyLayer`	CLIENT, PROXY, GATEWAY, UPSTREAM, APPLICATION, INFRA.
`recommendedNextSteps`	Ordered strings.
`commonMisinterpretations`	Optional clarifications.
`relatedHttpSpecs` / `relatedHeadersOfInterest`	Optional reference lists.
`retryRecommendation`	YES, NO, or CONDITIONAL.
`severityHint`	INFORMATIONAL, WARNING, CRITICAL.

HTTP	`error`	Meaning
400	`INVALID_REQUEST`	Missing/invalid body; missing `statusCode`; batch not an array or empty; bad event at index.
400	`INVALID_STATUS_CODE`	`/analyze`: status not in 400–599.
400/413	(parser)	Invalid JSON or body over Express 1MB limit.
500	`INTERNAL_ERROR`	Unexpected failure.

Try it in the playground

Switch between single and batch, pick a sample, add your RapidAPI key, run or copy code.

RapidAPI Key (required)

Endpoint

Sample

Batch mode requires a JSON array of events.

Request body (JSON)

Subscribe on RapidAPI for production quotas.

Get code

Reflects the playground. Host: api-fault-analysis-engine.p.rapidapi.com.

Integration time: One POST from your alert webhook or pipeline.

Real-world examples

1. Gateway 502 with Envoy timing

Include duration, responseHeaders like x-envoy-upstream-service-time, and proxyType: "envoy" to separate fast upstream refusal from slow timeouts.

2. Weekly error digest

POST an array of representative events to /analyze/batch and sort by summary.categoryCounts.

3. Retry policy hints

Use retryRecommendation and severityHint as signals—not as automatic retry engines.

Pricing & tiers (RapidAPI)

Built for high-volume alert and pipeline enrichment.

Plans on RapidAPI:

Basic

$0/mo

100 requests/month included

Pro

$9.99/mo

10,000 requests/month included

Popular

Ultra

$49.99/mo

100,000 requests/month included

Mega

$99.99/mo

250,000 requests/month included

Overage follows the live RapidAPI listing.

What to expect

200 with an analysis object or batch wrapper on success. 400 for validation issues. Oversized or malformed JSON may fail before handlers. 500 on rare internal errors.

About this API

Also known as

API fault analysis engine, HTTP root cause classifier, error triage API.

Trigger categories include client, auth, rate limits, proxy/TLS, timeouts, dependency failures, routing, infra limits, retry storms, and more—see the README for the full enum.

Frequently asked questions

No. You only send a JSON description of what already happened.
1MB per request.
Stateless processing; not persisted by this product.
No—deterministic rules from HTTP and common proxy behavior.
400–599 only for each event.
One object vs non-empty array plus summary category counts.
On RapidAPI: Basic 100/mo; Pro $9.99/10k; Ultra $49.99/100k; Mega $99.99/250k.
statusCode alone works; headers and duration improve confidence.

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