{"record":{"id":"8639e56698593090","repo":"gofiber/fiber","slug":"binder-suitable-content-not-found-to-parse-body","errorCode":null,"errorMessage":"binder: suitable content not found to parse body","messagePattern":"binder: suitable content not found to parse body","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"warning","filePath":"binder/binder.go","lineNumber":19,"sourceCode":"package binder\n\nimport (\n\t\"errors\"\n\t\"sync\"\n)\n\nconst (\n\tbindingURI        = \"uri\"\n\tbindingForm       = \"form\"\n\tbindingQuery      = \"query\"\n\tbindingHeader     = \"header\"\n\tbindingRespHeader = \"respHeader\"\n\tbindingCookie     = \"cookie\"\n)\n\n// Binder errors\nvar (\n\tErrSuitableContentNotFound = errors.New(\"binder: suitable content not found to parse body\")\n\tErrMapNotConvertible       = errors.New(\"binder: map is not convertible to map[string]string or map[string][]string\")\n\tErrMapNilDestination       = errors.New(\"binder: map destination is nil and cannot be initialized\")\n\tErrInvalidDestinationValue = errors.New(\"binder: invalid destination value\")\n\tErrUnmatchedBrackets       = errors.New(\"unmatched brackets\")\n)\n\nvar errPoolTypeAssertion = errors.New(\"failed to type-assert to T\")\n\nvar HeaderBinderPool = sync.Pool{\n\tNew: func() any {\n\t\treturn &HeaderBinding{}\n\t},\n}\n\nvar RespHeaderBinderPool = sync.Pool{\n\tNew: func() any {\n\t\treturn &RespHeaderBinding{}\n\t},","sourceCodeStart":1,"sourceCodeEnd":37,"githubUrl":"https://github.com/gofiber/fiber/blob/a105acad6c1e4576a77f01e02973f67e962bb58d/binder/binder.go#L1-L37","documentation":"Exported sentinel from the binder package indicating that no registered binder matches the request's Content-Type (binder/binder.go:19). It is intended for callers that build their own content-type dispatch on top of binder pools; Fiber's built-in Bind.Body() returns fiber.ErrUnprocessableEntity (422) for the same condition rather than this sentinel.","triggerScenarios":"A request carries a Content-Type the binder layer does not recognize (e.g. text/csv, application/graphql) and the application calls a custom dispatcher that returns ErrSuitableContentNotFound; or you use binder package types directly without registering a custom binder for that MIME type.","commonSituations":"Custom content negotiation where the client sends an uncommon media type; forgetting to register app.Config.CustomBinders for a new MIME; clients that send a malformed or empty Content-Type header with a body.","solutions":["Register a custom binder implementing MIMETypes() that lists the media type, then app.Config.CustomBinders = []binder.CustomBinder{...} so Bind.Body() dispatches to it.","If using binder types directly, switch on Content-Type yourself and fall back to a sensible default (e.g. JSON) instead of returning the sentinel.","Reject unsupported media types early in middleware with 415 Unsupported Media Type so the binder never sees them.","Align the client to send only Content-Types your server understands."],"exampleFix":"// before: unknown content-type reaches the binder\nctype := header.ContentType()\n// ...falls through every case, returns ErrSuitableContentNotFound\n\n// after: register a custom binder for the MIME\napp.Config().CustomBinders = []binder.CustomBinder{&CSVBinder{}}\n// where CSVBinder.MIMETypes() returns []string{\"text/csv\"}","handlingStrategy":"validation","validationCode":"// Validate Content-Type before dispatching to a binder\nfunc supportedCType(ctype string) bool {\n    switch ctype {\n    case fiber.MIMEApplicationJSON, fiber.MIMEApplicationXML, fiber.MIMETextXML,\n        fiber.MIMEApplicationCBOR, fiber.MIMEApplicationMsgPack,\n        fiber.MIMEApplicationForm, fiber.MIMEMultipartForm:\n        return true\n    }\n    // also accept any MIME covered by a registered custom binder\n    return false\n}","typeGuard":null,"tryCatchPattern":"if err := c.Bind().Body(&out); err != nil {\n    if errors.Is(err, binder.ErrSuitableContentNotFound) || errors.Is(err, fiber.ErrUnprocessableEntity) {\n        return c.Status(fiber.StatusUnsupportedMediaType).SendString(\"unsupported media type\")\n    }\n    return err\n}","preventionTips":["Register custom binders for every MIME type your API advertises.","Reject unknown Content-Types at a middleware boundary with 415.","Document the supported media types in your API spec and validate at the edge."],"tags":["binding","content-type","fiber","http"],"backgroundTag":null,"analyzedSha":"a105acad6c1e4576a77f01e02973f67e962bb58d","analyzedAt":"2026-08-11T17:33:26.942Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-23T08:17:48.524Z"}