[{"_1":2,"_3":-5,"_4":-5},"loaderData",{"_5":6},"actionData","errors","docs-en",{"_7":8,"_9":10,"_11":12,"_13":14,"_15":16,"_17":18,"_19":20,"_21":22,"_23":24,"_25":26},"openapiData",{"_250":251},"locale","en","path","reference/proxy-api/checkProxy.mdx","url","/docs/en/reference/proxy-api/checkProxy","title","Health check","description","","markdownUrl","/docs/en/llms.mdx/reference/proxy-api/checkProxy/content.md","imageUrl","/docs/en/og/reference/proxy-api/checkProxy/image.png","lastModified","2026-10-14T03:59:41.000Z","pageTree",{"_27":28,"_29":30},"$fumadocs_loader","page-tree","data",{"_31":32,"_33":34,"_35":36,"_37":38,"_17":-7,"_39":40},"type","root","$ref",{"_53":18,"_63":249},"$id","en:root","name","Docs","children",[41,42,43,44,45,46,47,48,49,50,51,52],{"_35":243,"_31":69,"_37":244,"_17":245,"_60":246,"_13":247,"_33":248},{"_35":237,"_31":69,"_37":238,"_17":239,"_60":240,"_13":241,"_33":242},{"_35":235,"_31":87,"_60":-7,"_37":236},{"_31":53,"_37":211,"_32":-7,"_55":-7,"_17":-7,"_56":-7,"_39":212,"_35":213,"_33":214,"_60":215},{"_31":53,"_37":176,"_32":-7,"_55":-7,"_17":-7,"_56":-7,"_39":177,"_35":178,"_33":179,"_60":180},{"_35":175,"_31":87,"_60":-7,"_37":149},{"_31":53,"_37":149,"_32":-7,"_55":-7,"_17":-7,"_56":-7,"_39":150,"_35":151,"_33":152,"_60":153},{"_35":147,"_31":87,"_60":-7,"_37":148},{"_31":53,"_37":121,"_32":-7,"_55":-7,"_17":-7,"_56":-7,"_39":122,"_35":123,"_33":124,"_60":125},{"_31":53,"_37":88,"_32":-7,"_55":-7,"_17":-7,"_56":-7,"_39":89,"_35":90,"_33":91,"_60":92},{"_35":86,"_31":87,"_60":-7,"_37":54},{"_31":53,"_37":54,"_32":-7,"_55":-7,"_17":-7,"_56":-7,"_39":57,"_35":58,"_33":59,"_60":61},"folder","Development","defaultOpen","collapsible",[65,66,67],"en:development",{"_53":62,"_63":64},"icon","","development","meta","development/meta.json",{"_35":81,"_31":69,"_37":82,"_17":83,"_60":61,"_13":84,"_33":85},{"_35":75,"_31":69,"_37":76,"_17":77,"_60":78,"_13":79,"_33":80},{"_35":68,"_31":69,"_37":70,"_17":71,"_60":72,"_13":73,"_33":74},"en:development/release.mdx","page","Packaging and publishing","What the CLI package contains, the automatic publishing workflow, and the first-time setup of npm trusted publishing.","","/docs/en/development/release","development/release.mdx","en:development/design.mdx","Design spec","Page composition, fonts and colors, motion, copy formats, and available primitives of the detector website, the docs, and the preview images, for anyone changing the interface.","","/docs/en/development/design","development/design.mdx","en:development/index.mdx","Project structure","What each directory in the Bun workspace does, the shared algorithm modules, and the conventions to follow when you change the code.","/docs/en/development","development/index.mdx","en:_3","separator","Reference",[95,96],"en:reference",{"_53":93,"_63":94},"","reference","reference/meta.json",{"_35":115,"_31":69,"_37":116,"_17":117,"_60":118,"_13":119,"_33":120},{"_31":53,"_37":97,"_32":-7,"_55":-7,"_17":-7,"_56":-7,"_39":98,"_35":99,"_33":100,"_60":-7},"Proxy API",[103,104,105],"en:reference/proxy-api",{"_53":101,"_63":102},"reference/proxy-api","reference/proxy-api/meta.json",{"_35":111,"_31":69,"_37":97,"_17":112,"_60":-7,"_13":113,"_33":114},{"_35":110,"_31":69,"_37":16,"_17":-7,"_60":-7,"_13":14,"_33":12},{"_35":106,"_31":69,"_37":107,"_17":-7,"_60":-7,"_13":108,"_33":109},"en:reference/proxy-api/relayRequest.mdx","Relay an API request","/docs/en/reference/proxy-api/relayRequest","reference/proxy-api/relayRequest.mdx","en:reference/proxy-api/checkProxy.mdx","en:reference/proxy-api/index.mdx","The HTTP API of the forwarding proxy, with a health check, request forwarding, and the cross-origin preflight. This site's proxy and your own Worker share the same API.","/docs/en/reference/proxy-api","reference/proxy-api/index.mdx","en:reference/data.mdx","Data files","The official reference samples, derived fingerprint bank, frozen detector, fixed challenges, and tokenizer bank in the data/ directory, and their change log.","","/docs/en/reference/data","reference/data.mdx","Deployment",[128,129,130],"en:deployment",{"_53":126,"_63":127},"","deployment","deployment/meta.json",{"_35":143,"_31":69,"_37":121,"_17":144,"_60":125,"_13":145,"_33":146},{"_35":137,"_31":69,"_37":138,"_17":139,"_60":140,"_13":141,"_33":142},{"_35":131,"_31":69,"_37":132,"_17":133,"_60":134,"_13":135,"_33":136},"en:deployment/proxy.mdx","Proxy constraints and local development","Which upstream addresses the same-origin proxy accepts, how it checks where requests come from, and how the dev and preview servers use the same implementation.","","/docs/en/deployment/proxy","deployment/proxy.mdx","en:deployment/worker.mdx","Own Worker proxy","Deploy worker/main.js to your own Cloudflare account to get a workers.dev address, so your API key does not pass through this site's proxy.","","/docs/en/deployment/worker","deployment/worker.mdx","en:deployment/index.mdx","Deploy the detection website, these docs, and the same-origin proxy to Cloudflare Pages, or publish them as a static site on GitHub Pages.","/docs/en/deployment","deployment/index.mdx","en:_2","Deployment and reference","How it works",[156,157,158],"en:principles",{"_53":154,"_63":155},"","principles","principles/meta.json",{"_35":170,"_31":69,"_37":171,"_17":172,"_60":153,"_13":173,"_33":174},{"_35":165,"_31":69,"_37":166,"_17":167,"_60":-7,"_13":168,"_33":169},{"_35":159,"_31":69,"_37":160,"_17":161,"_60":162,"_13":163,"_33":164},"en:principles/tokenizer.mdx","Tokenizer probe","The probe cancels hidden input with differential counts, makes a Bayesian open-set decision between 62 open tokenizer classes and \"unlisted\", and picks probe texts by a pairwise upper bound on the error. The result is reference information shown next to the ranking and checked against the model you entered.","","/docs/en/principles/tokenizer","principles/tokenizer.mdx","en:principles/ranking.mdx","Ranking and calibration","A frequency ranking and a position/order discriminant set the candidate order with equal weights, and a temperature softmax gives the confidence within the reference bank.","/docs/en/principles/ranking","principles/ranking.mdx","en:principles/index.mdx","Overview","How the detector turns an answer into a comparable fingerprint, from challenge prompts and integer parsing to numeric features.","/docs/en/principles","principles/index.mdx","en:_1","Command line",[183,184,185,186,187],"en:cli",{"_53":181,"_63":182},"","cli","cli/meta.json",{"_35":207,"_31":69,"_37":176,"_17":208,"_60":180,"_13":209,"_33":210},{"_35":202,"_31":69,"_37":203,"_17":204,"_60":-7,"_13":205,"_33":206},{"_35":198,"_31":69,"_37":160,"_17":199,"_60":-7,"_13":200,"_33":201},{"_35":193,"_31":69,"_37":194,"_17":195,"_60":-7,"_13":196,"_33":197},{"_35":188,"_31":69,"_37":189,"_17":190,"_60":-7,"_13":191,"_33":192},"en:cli/enroll.mdx","Enrollment and retraining","Validate a sampling batch, deduplicate it, and write it to the reference bank, then retrain the ranker and confidence calibration offline.","/docs/en/cli/enroll","cli/enroll.mdx","en:cli/sampling.mdx","Sampling and resuming","Collect a reference batch for a new model or channel with the 36 fixed challenges, resume after an interruption, and adjust single challenges or adopt truncated answers.","/docs/en/cli/sampling","cli/sampling.mdx","en:cli/tokenizer.mdx","With --tokenizer, fpd identifies the tokenizer behind the API during detection and checks it against the model you entered. The result is reference only. It does not change the ranking or delay the result.","/docs/en/cli/tokenizer","cli/tokenizer.mdx","en:cli/detect.mdx","Detection","Check an API channel with random challenges over several rounds, save the report, and recompute it offline.","/docs/en/cli/detect","cli/detect.mdx","en:cli/index.mdx","How to run fpd, its subcommands, environment variables, and update notifications.","/docs/en/cli","cli/index.mdx","Website",[218,219,220],"en:web",{"_53":216,"_63":217},"","web","web/meta.json",{"_35":231,"_31":69,"_37":211,"_17":232,"_60":215,"_13":233,"_33":234},{"_35":227,"_31":69,"_37":160,"_17":228,"_60":162,"_13":229,"_33":230},{"_35":221,"_31":69,"_37":222,"_17":223,"_60":224,"_13":225,"_33":226},"en:web/connection.mdx","Connection","The Connection setting decides whether the browser calls the API directly or sends requests through this site's proxy or a Worker you deploy yourself. By default, requests go through this site's proxy. Auto first checks whether the API allows web pages to call it directly and otherwise uses this site's proxy.","","/docs/en/web/connection","web/connection.mdx","en:web/tokenizer.mdx","While sampling, API detection identifies the upstream tokenizer and checks whether it matches the model you entered. The result is reference information; it neither changes the ranking nor delays the detection result.","/docs/en/web/tokenizer","web/tokenizer.mdx","en:web/index.mdx","The manual and API sampling modes, the switches in the API configuration, and how to read detection results.","/docs/en/web","web/index.mdx","en:_0","Usage","en:quick-start.mdx","Quick start","Run one detection on the website, or run fpd in a terminal without installing anything.","","/docs/en/quick-start","quick-start.mdx","en:index.mdx","LM Fingerpoint Detector","Identify the LLM behind an API from a few hundred casually written integers.","","/docs/en","index.mdx","meta.json","preloaded",{"_252":253,"_254":-7},"docs",{"_255":256},"proxyUrl","../worker/openapi.json",{"_257":258,"_259":260,"_261":262,"_263":264,"_265":266,"_267":268},"openapi","3.2.0","info",{"_15":465,"_466":467,"_17":468,"_469":470},"servers",[453,454],"tags",[451],"paths",{"_356":357},"components",{"_269":270,"_271":272,"_273":274},"securitySchemes",{"_350":351},"schemas",{"_291":292,"_293":294,"_275":295},"responses",{"_275":276,"_277":278},"Error",{"_17":287,"_280":288},"Forbidden",{"_17":279,"_280":281},"The page's origin may not use this proxy, or a same-origin proxy received a cross-site request.","content",{"_282":283},"application/json",{"_284":285},"schema",{"_33":286},"#/components/schemas/Error","An error raised by the proxy itself.",{"_282":289},{"_284":290},{"_33":286},"RelayRequest",{"_31":296,"_297":323,"_299":324},"Health",{"_31":296,"_297":308,"_299":309},{"_31":296,"_297":298,"_299":300},"object","required",[301],"properties",{"_301":302},"error",{"_31":296,"_297":303,"_299":304},[305],{"_305":306},"message",{"_31":307},"string",[310,312],{"_310":311,"_312":313},"service",{"_31":307,"_321":322},"formats",{"_31":314,"_315":316},"array","items",{"_31":307,"_317":318},"enum",[319,273,320],"openai","anthropic","const","fingerpoint-api-proxy",[13,326,328],{"_13":325,"_326":327,"_328":329},{"_31":307,"_326":345,"_17":346,"_347":348},"format",{"_31":307,"_317":343,"_17":344},"body",{"_31":296,"_297":330,"_299":331,"_332":333,"_17":334},[335],{"_335":336,"_337":338},"additionalProperties",true,"The request body for the upstream API, sent as it is.","model",{"_31":307,"_341":342},"stream",{"_31":339,"_17":340},"boolean","Selects the SSE `Accept` header upstream.","minLength",1,[319,273,320],"Chat Completions, Responses or Messages.","uri","The complete upstream endpoint: HTTPS on port 443, a public host name, no credentials, query or fragment, ending in `/chat/completions`, `/responses` or `/messages` for the chosen format.","examples",[349],"https://api.example.com/v1/chat/completions","upstreamKey",{"_31":352,"_353":354,"_17":355},"http","scheme","bearer","The API key of the upstream service. The proxy does not store it.","/api/proxy",{"_358":359,"_360":361,"_362":363},"get",{"_364":440,"_263":441,"_367":16,"_17":442,"_273":443},"post",{"_364":391,"_263":392,"_367":107,"_17":393,"_394":395,"_396":397,"_273":398},"options",{"_364":365,"_263":366,"_367":368,"_17":369,"_370":371,"_273":372},"operationId","preflight",[390],"summary","CORS preflight","Answered by a self-deployed Worker for the origins in `ALLOWED_ORIGINS`. Browsers send it on their own before a cross-origin `POST`.","parameters",[379,380],{"_373":374,"_375":376},"204",{"_17":378},"403",{"_17":377},"The origin is not allowed; the response has no CORS headers.","The origin is allowed. The response carries `Access-Control-Allow-Origin`, `Access-Control-Allow-Methods: GET, POST, OPTIONS`, `Access-Control-Allow-Headers: authorization, content-type` and `Access-Control-Max-Age: 7200`.",{"_37":387,"_382":383,"_297":333,"_284":388,"_385":389},{"_37":381,"_382":383,"_297":333,"_284":384,"_385":386},"Access-Control-Request-Method","in","header",{"_31":307},"example","POST","Origin",{"_31":307},"https://lm.ikale.io","proxy","relayRequest",[390],"Sends `body` to the upstream endpoint `url` with the caller's key and streams the JSON or SSE response back unchanged, including the upstream status. For `anthropic`, the key goes upstream as `x-api-key` with `anthropic-version: 2023-06-01`, plus `anthropic-beta: fast-mode-2026-02-01` when `body` contains `speed`; otherwise as `Authorization`. Redirects are not followed and cookies are not forwarded. The upstream request times out after 250 seconds, and cancelling the call cancels it.","security",[438],"requestBody",{"_297":333,"_280":434},{"_399":400,"_401":402,"_403":404,"_375":405,"_406":407,"_408":409,"_410":411,"_412":413,"_414":415},"200",{"_17":425,"_280":426},"400",{"_33":416,"_17":424},"401",{"_33":416,"_17":423},{"_33":422},"413",{"_33":416,"_17":421},"415",{"_33":416,"_17":420},"499",{"_33":416,"_17":419},"502",{"_33":416,"_17":418},"504",{"_33":416,"_17":417},"#/components/responses/Error","The upstream did not answer within 250 seconds.","The upstream redirected, returned an unsupported content type with a success status, or could not be reached.","The caller cancelled the request.","The request is not `application/json`.","The request body exceeds 128 KiB.","#/components/responses/Forbidden","The `Authorization: Bearer` header is missing.","The body is not a JSON object, the protocol is unsupported, the model is missing, or the upstream URL is not a public HTTPS endpoint of the protocol.","The upstream response, streamed unchanged. Other upstream statuses, such as 401 or 429, are relayed as they are.",{"_282":427,"_428":429},{"_284":432},"text/event-stream",{"_284":430},{"_31":307,"_17":431},"The upstream SSE stream.",{"_31":296,"_17":433},"The upstream JSON body.",{"_282":435},{"_284":436},{"_33":437},"#/components/schemas/RelayRequest",{"_350":439},[],"checkProxy",[390],"Identifies a Fingerpoint proxy. The web app calls it from Check proxy; it takes no key and sends nothing upstream.",{"_399":444,"_375":445},{"_17":446,"_280":447},{"_33":422},"The proxy is available.",{"_282":448},{"_284":449},{"_33":450},"#/components/schemas/Health",{"_37":390,"_17":452},"Relay and health check",{"_13":389,"_17":464},{"_13":455,"_17":456,"_457":458},"https://{worker}","A self-deployed Worker","variables",{"_459":460},"worker",{"_461":462,"_17":463},"default","fingerpoint-api-proxy.example.workers.dev","Host name of the Worker","Site proxy, for pages served from lm.ikale.io","Fingerpoint API proxy","version","1.0.0","A transparent HTTPS relay for LLM API requests from browsers, implemented by `worker/main.js`. The site proxy at `/api/proxy` accepts same-origin calls only; a self-deployed Worker also accepts the origins listed in `ALLOWED_ORIGINS` and answers on any path.","license",{"_37":471,"_13":472},"MIT","https://github.com/Ikaleio/lm-detector/blob/main/LICENSE"]

Health check

Response BodyCopy Anchor Link

200application/json

403application/json

Response Body

`application/json`

`application/json`