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  1. Web technology for developers
  2. HTTP
  3. HTTP response status codes
  4. 425 Too Early
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Table of contents

  • Status
  • Specifications
  • Browser compatibility

425 Too Early

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The HyperText Transfer Protocol (HTTP) 425 Too Early response status code indicates that the server is unwilling to risk processing a request that might be replayed, which creates the potential for a replay attack.

Status

425 Too Early

Specifications

Specification
Using Early Data in HTTP
# status

Browser compatibility

BCD tables only load in the browser

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Last modified: Aug 13, 2021, by MDN contributors

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Related Topics

  1. HTTP
  2. Guides:
  3. Resources and URIs
    1. Identifying resources on the Web
    2. Data URIs
    3. Introduction to MIME types
    4. Common MIME types
    5. Choosing between www and non-www URLs
  4. HTTP guide
    1. Basics of HTTP
    2. Overview of HTTP
    3. Evolution of HTTP
    4. HTTP Messages
    5. A typical HTTP session
    6. Connection management in HTTP/1.x
    7. Protocol upgrade mechanism
  5. HTTP security
    1. Content Security Policy (CSP)
    2. HTTP Public Key Pinning (HPKP)
    3. HTTP Strict Transport Security (HSTS)
    4. Cookie security
    5. X-Content-Type-Options
    6. X-Frame-Options
    7. X-XSS-Protection
    8. Mozilla web security guidelines
    9. Mozilla Observatory
  6. HTTP access control (CORS)
  7. HTTP authentication
  8. HTTP caching
  9. HTTP compression
  10. HTTP conditional requests
  11. HTTP content negotiation
  12. HTTP cookies
  13. HTTP range requests
  14. HTTP redirects
  15. HTTP specifications
  16. Feature policy
  17. References:
  18. HTTP headers
    1. Accept-CH-Lifetime
    2. Accept-CH
    3. Accept-Charset
    4. Accept-Encoding
    5. Accept-Language
    6. Accept-Patch
    7. Accept-Post
    8. Accept-Ranges
    9. Accept
    10. Access-Control-Allow-Credentials
    11. Access-Control-Allow-Headers
    12. Access-Control-Allow-Methods
    13. Access-Control-Allow-Origin
    14. Access-Control-Expose-Headers
    15. Access-Control-Max-Age
    16. Access-Control-Request-Headers
    17. Access-Control-Request-Method
    18. Age
    19. Allow
    20. Alt-Svc
    21. Authorization
    22. Cache-Control
    23. Clear-Site-Data
    24. Connection
    25. Content-Disposition
    26. Content-DPR
    27. Content-Encoding
    28. Content-Language
    29. Content-Length
    30. Content-Location
    31. Content-Range
    32. Content-Security-Policy-Report-Only
    33. Content-Security-Policy
    34. Content-Type
    35. Cookie
    36. Cross-Origin-Embedder-Policy
    37. Cross-Origin-Opener-Policy
    38. Cross-Origin-Resource-Policy
    39. Date
    40. Device-Memory
    41. Digest
    42. DNT
    43. Downlink
    44. DPR
    45. Early-Data
    46. ECT
    47. ETag
    48. Expect-CT
    49. Expect
    50. Expires
    51. Feature-Policy
    52. Forwarded
    53. From
    54. Host
    55. If-Match
    56. If-Modified-Since
    57. If-None-Match
    58. If-Range
    59. If-Unmodified-Since
    60. Keep-Alive
    61. Large-Allocation
    62. Last-Modified
    63. Link
    64. Location
    65. NEL
    66. Origin
    67. Pragma
    68. Proxy-Authenticate
    69. Proxy-Authorization
    70. Public-Key-Pins-Report-Only
    71. Public-Key-Pins
    72. Range
    73. Referer
    74. Referrer-Policy
    75. Retry-After
    76. RTT
    77. Save-Data
    78. Sec-CH-UA-Arch
    79. Sec-CH-UA-Bitness
    80. Sec-CH-UA-Full-Version-List
    81. Sec-CH-UA-Full-Version
    82. Sec-CH-UA-Mobile
    83. Sec-CH-UA-Model
    84. Sec-CH-UA-Platform-Version
    85. Sec-CH-UA-Platform
    86. Sec-CH-UA
    87. Sec-Fetch-Dest
    88. Sec-Fetch-Mode
    89. Sec-Fetch-Site
    90. Sec-Fetch-User
    91. Sec-WebSocket-Accept
    92. Server-Timing
    93. Server
    94. Service-Worker-Navigation-Preload
    95. Set-Cookie
    96. SourceMap
    97. Strict-Transport-Security
    98. TE
    99. Timing-Allow-Origin
    100. Tk
    101. Trailer
    102. Transfer-Encoding
    103. Upgrade-Insecure-Requests
    104. Upgrade
    105. User-Agent
    106. Vary
    107. Via
    108. Viewport-Width
    109. Want-Digest
    110. Warning
    111. Width
    112. WWW-Authenticate
    113. X-Content-Type-Options
    114. X-DNS-Prefetch-Control
    115. X-Forwarded-For
    116. X-Forwarded-Host
    117. X-Forwarded-Proto
    118. X-Frame-Options
    119. X-XSS-Protection
  19. HTTP request methods
    1. CONNECT
    2. DELETE
    3. GET
    4. HEAD
    5. OPTIONS
    6. PATCH
    7. POST
    8. PUT
    9. TRACE
  20. HTTP response status codes
    1. 100 Continue
    2. 101 Switching Protocols
    3. 103 Early Hints
    4. 200 OK
    5. 201 Created
    6. 202 Accepted
    7. 203 Non-Authoritative Information
    8. 204 No Content
    9. 205 Reset Content
    10. 206 Partial Content
    11. 300 Multiple Choices
    12. 301 Moved Permanently
    13. 302 Found
    14. 303 See Other
    15. 304 Not Modified
    16. 307 Temporary Redirect
    17. 308 Permanent Redirect
    18. 400 Bad Request
    19. 401 Unauthorized
    20. 402 Payment Required
    21. 403 Forbidden
    22. 404 Not Found
    23. 405 Method Not Allowed
    24. 406 Not Acceptable
    25. 407 Proxy Authentication Required
    26. 408 Request Timeout
    27. 409 Conflict
    28. 410 Gone
    29. 411 Length Required
    30. 412 Precondition Failed
    31. 413 Payload Too Large
    32. 414 URI Too Long
    33. 415 Unsupported Media Type
    34. 416 Range Not Satisfiable
    35. 417 Expectation Failed
    36. 418 I'm a teapot
    37. 422 Unprocessable Entity
    38. 425 Too Early
    39. 426 Upgrade Required
    40. 428 Precondition Required
    41. 429 Too Many Requests
    42. 431 Request Header Fields Too Large
    43. 451 Unavailable For Legal Reasons
    44. 500 Internal Server Error
    45. 501 Not Implemented
    46. 502 Bad Gateway
    47. 503 Service Unavailable
    48. 504 Gateway Timeout
    49. 505 HTTP Version Not Supported
    50. 506 Variant Also Negotiates
    51. 507 Insufficient Storage
    52. 508 Loop Detected
    53. 510 Not Extended
    54. 511 Network Authentication Required
  21. CSP directives
    1. CSP: base-uri
    2. CSP: block-all-mixed-content
    3. CSP: child-src
    4. CSP: connect-src
    5. CSP: default-src
    6. CSP: font-src
    7. CSP: form-action
    8. CSP: frame-ancestors
    9. CSP: frame-src
    10. CSP: img-src
    11. CSP: manifest-src
    12. CSP: media-src
    13. CSP: navigate-to
    14. CSP: object-src
    15. CSP: plugin-types
    16. CSP: prefetch-src
    17. CSP: referrer
    18. CSP: report-to
    19. CSP: report-uri
    20. CSP: require-sri-for
    21. CSP: require-trusted-types-for
    22. CSP: sandbox
    23. CSP: script-src-attr
    24. CSP: script-src-elem
    25. CSP: script-src
    26. CSP source values
    27. CSP: style-src-attr
    28. CSP: style-src-elem
    29. CSP: style-src
    30. CSP: trusted-types
    31. CSP: upgrade-insecure-requests
    32. CSP: worker-src
  22. CORS errors
    1. Reason: CORS header 'Access-Control-Allow-Origin' does not match 'xyz'
    2. Reason: CORS request did not succeed
    3. Reason: CORS disabled
    4. Reason: CORS request external redirect not allowed
    5. Reason: invalid token 'xyz' in CORS header 'Access-Control-Allow-Headers'
    6. Reason: invalid token 'xyz' in CORS header 'Access-Control-Allow-Methods'
    7. Reason: Did not find method in CORS header 'Access-Control-Allow-Methods'
    8. Reason: expected 'true' in CORS header 'Access-Control-Allow-Credentials'
    9. Reason: missing token 'xyz' in CORS header 'Access-Control-Allow-Headers' from CORS preflight channel
    10. Reason: CORS header 'Access-Control-Allow-Origin' missing
    11. Reason: Multiple CORS header 'Access-Control-Allow-Origin' not allowed
    12. Reason: Credential is not supported if the CORS header 'Access-Control-Allow-Origin' is '*'
    13. Reason: CORS header 'Origin' cannot be added
    14. Reason: CORS preflight channel did not succeed
    15. Reason: CORS request not HTTP
  23. Feature-Policy directives
    1. Feature-Policy: accelerometer
    2. Feature-Policy: ambient-light-sensor
    3. Feature-Policy: autoplay
    4. Feature-Policy: battery
    5. Feature-Policy: camera
    6. Feature-Policy: display-capture
    7. Feature-Policy: document-domain
    8. Feature-Policy: encrypted-media
    9. Feature-Policy: fullscreen
    10. Feature-Policy: gamepad
    11. Feature-Policy: geolocation
    12. Feature-Policy: gyroscope
    13. Feature-Policy: layout-animations
    14. Feature-Policy: legacy-image-formats
    15. Feature-Policy: magnetometer
    16. Feature-Policy: microphone
    17. Feature-Policy: midi
    18. Feature-Policy: oversized-images
    19. Feature-Policy: payment
    20. Feature-Policy: picture-in-picture
    21. Feature-Policy: publickey-credentials-get
    22. Feature-Policy: screen-wake-lock
    23. Feature-Policy: speaker-selection
    24. Feature-Policy: sync-xhr
    25. Feature-Policy: unoptimized-images
    26. Feature-Policy: unsized-media
    27. Feature-Policy: usb
    28. Feature-Policy: web-share
    29. Feature-Policy: xr-spatial-tracking
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