NHS Digital · API Governance Rules

NHS Digital API Rules

Spectral linting rules defining API design standards and conventions for NHS Digital.

52 Rules error 50 warn 1 info 1
Generated by API Evangelist Written by API Evangelist tooling for NHS Digital's APIs. It is a starting point, not a ruleset NHS Digital publishes or enforces.
View Rules File View on GitHub

Rule Categories

contact info license mediatype operation parameter path requestbody response securityscheme server servers tag

Rules

error
operation-has-operationid
Every operation declares an operationId (measured: 100% of this contract)
$.paths[*][get,post,put,patch,delete]
error
operation-has-summary
Every operation has a summary (measured: 100% of this contract)
$.paths[*][get,post,put,patch,delete]
error
operation-has-tags
Every operation is tagged (measured: 100% of this contract)
$.paths[*][get,post,put,patch,delete]
error
path-no-trailing-slash
Paths carry no trailing slash (measured: 100% of this contract)
$.paths[*]~
error
path-params-in-braces
Path parameters use {braces}, not :colon (measured: 100% of this contract)
$.paths[*]~
error
servers-https
Servers are https (measured: 100% of this contract)
$.servers[*].url
warn
response-media-type
Responses are served as application/fhir+json (measured: 93% of this contract)
$.paths[*][get,post,put,patch,delete].responses[*].content
error
info-has-description
The contract's info block carries a description (measured: 100% of this contract)
$.info
error
info-has-contact-or-terms
The contract's info block names a contact or terms of service (measured: 100% of this contract)
$.info
error
info-title-present
Info declares title (measured: 100% of this contract)
$.info
error
info-title-min-length
Info.title runs at least 20 characters (measured: 100% of this contract)
$.info.title
error
info-description-present
Info declares description (measured: 100% of this contract)
$.info
error
info-description-min-length
Info.description runs at least 61 characters (measured: 100% of this contract)
$.info.description
error
info-termsofservice-https
Info.termsOfService is https (measured: 100% of this contract)
$.info.termsOfService
error
info-contact-present
Info declares contact (measured: 100% of this contract)
$.info
info
info-license-present
Info declares license (measured: 87% of this contract)
$.info
error
info-version-present
Info declares version (measured: 100% of this contract)
$.info
error
info-version-semver
info.version is numeric (measured: 100% of this contract)
$.info.version
error
contact-url-present
Contact declares url (measured: 100% of this contract)
$.info.contact
error
contact-url-https
Contact.url is https (measured: 100% of this contract)
$.info.contact.url
error
contact-email-present
Contact declares email (measured: 100% of this contract)
$.info.contact
error
license-name-present
License declares name (measured: 100% of this contract)
$.info.license
error
server-url-present
Server declares url (measured: 100% of this contract)
$.servers[*]
error
server-url-https
Server.url is https (measured: 100% of this contract)
$.servers[*].url
error
server-description-present
Server declares description (measured: 100% of this contract)
$.servers[*]
error
server-description-min-length
Server.description runs at least 10 characters (measured: 100% of this contract)
$.servers[*].description
error
tag-name-present
Tag declares name (measured: 100% of this contract)
$.tags[*]
error
tag-name-casing-pascal
Tag.name is pascal case (measured: 100% of this contract)
$.tags[*].name
error
operation-tags-present
Operation declares tags (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace]
error
operation-summary-present
Operation declares summary (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace]
error
operation-summary-min-length
Operation.summary runs at least 9 characters (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].summary
error
operation-description-min-length
Operation.description runs at least 343 characters (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].description
error
operation-operationid-present
Operation declares operationId (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace]
error
parameter-name-present
Parameter declares name (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*]
error
parameter-in-present
Parameter declares in (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*]
error
parameter-in-values
Parameter.in is one of query (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*].in
error
parameter-description-present
Parameter declares description (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*]
error
parameter-description-min-length
Parameter.description runs at least 47 characters (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*].description
error
parameter-required-present
Parameter declares required (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*]
error
parameter-schema-present
Parameter declares schema (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*]
error
requestbody-content-present
RequestBody declares content (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].requestBody
error
requestbody-required-present
RequestBody declares required (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].requestBody
error
mediatype-schema-present
MediaType declares schema (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].responses[*].content[*]
error
response-description-present
Response declares description (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].responses[*]
error
response-description-min-length
Response.description runs at least 7 characters (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].responses[*].description
error
response-headers-present
Response declares headers (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].responses[*]
error
response-content-present
Response declares content (measured: 100% of this contract)
$.paths[*][get,put,post,delete,patch,options,head,trace].responses[*]
error
securityscheme-type-present
SecurityScheme declares type (measured: 100% of this contract)
$.components.securitySchemes[*]
error
securityscheme-type-values
SecurityScheme.type is one of http (measured: 100% of this contract)
$.components.securitySchemes[*].type
error
securityscheme-scheme-present
SecurityScheme declares scheme (measured: 100% of this contract)
$.components.securitySchemes[*]
error
securityscheme-scheme-values
SecurityScheme.scheme is one of bearer (measured: 100% of this contract)
$.components.securitySchemes[*].scheme
error
securityscheme-bearerformat-values
SecurityScheme.bearerFormat is one of JWT (measured: 100% of this contract)
$.components.securitySchemes[*].bearerFormat

Spectral Ruleset

Raw ↑ 
# authorship: generated by API Evangelist tooling (derive-rules.py, 2026-11-01). x-method: generated
# Every rule below was MEASURED against NHS Digital's own contract before it was written; a rule is present only
# when the contract satisfies it at 80% or more. Severity: 100% -> error, >= 90% -> warn, else info.
# Provenance:
#   - operation-has-operationid: 100%
#   - operation-has-summary: 100%
#   - operation-has-tags: 100%
#   - path-no-trailing-slash: 100%
#   - path-params-in-braces: 100%
#   - servers-https: 100%
#   - response-media-type: 93%
#   - info-has-description: 100%
#   - info-has-contact-or-terms: 100%
#   - info-title-present: 100%
#   - info-title-min-length: 100%
#   - info-description-present: 100%
#   - info-description-min-length: 100%
#   - info-termsofservice-https: 100%
#   - info-contact-present: 100%
#   - info-license-present: 88%
#   - info-version-present: 100%
#   - info-version-semver: 100%
#   - contact-url-present: 100%
#   - contact-url-https: 100%
#   - contact-email-present: 100%
#   - license-name-present: 100%
#   - server-url-present: 100%
#   - server-url-https: 100%
#   - server-description-present: 100%
#   - server-description-min-length: 100%
#   - tag-name-present: 100%
#   - tag-name-casing-pascal: 100%
#   - operation-tags-present: 100%
#   - operation-summary-present: 100%
#   - operation-summary-min-length: 100%
#   - operation-description-min-length: 100%
#   - operation-operationid-present: 100%
#   - parameter-name-present: 100%
#   - parameter-in-present: 100%
#   - parameter-in-values: 100%
#   - parameter-description-present: 100%
#   - parameter-description-min-length: 100%
#   - parameter-required-present: 100%
#   - parameter-schema-present: 100%
#   - requestbody-content-present: 100%
#   - requestbody-required-present: 100%
#   - mediatype-schema-present: 100%
#   - response-description-present: 100%
#   - response-description-min-length: 100%
#   - response-headers-present: 100%
#   - response-content-present: 100%
#   - securityscheme-type-present: 100%
#   - securityscheme-type-values: 100%
#   - securityscheme-scheme-present: 100%
#   - securityscheme-scheme-values: 100%
#   - securityscheme-bearerformat-values: 100%
x-method: generated
x-generator: derive-rules.py
x-generated: '2026-11-01'
x-source:
- openapi/nhs-digital-booking-api-openapi.yml
- openapi/nhs-digital-communication-api-openapi.yml
- openapi/nhs-digital-message-api-openapi.yml
- openapi/nhs-digital-metadata-api-openapi.yml
- openapi/nhs-digital-r4-api-openapi.yml
x-self-check:
  status: checked
  rules: 56
  dropped:
    operation-description-present: claims 100%, failed 40
    operation-responses-present: claims 100%, failed 40
    header-description-present: claims 100%, failed 23
    header-schema-present: claims 100%, failed 23
extends:
- - spectral:oas
  - recommended
formats:
- oas3
rules:
  operation-has-operationid:
    description: 'Every operation declares an operationId (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,post,put,patch,delete]
    then:
      field: operationId
      function: truthy
    x-pattern-key: Operation.operationId|present
  operation-has-summary:
    description: 'Every operation has a summary (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,post,put,patch,delete]
    then:
      field: summary
      function: truthy
    x-pattern-key: Operation.summary|present
  operation-has-tags:
    description: 'Every operation is tagged (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,post,put,patch,delete]
    then:
      field: tags
      function: truthy
    x-pattern-key: Operation.tags|present
  path-no-trailing-slash:
    description: 'Paths carry no trailing slash (measured: 100% of this contract)'
    severity: error
    given: $.paths[*]~
    then:
      function: pattern
      functionOptions:
        notMatch: ./$
    x-pattern-key: Paths.{key}|pattern:!./$
  path-params-in-braces:
    description: 'Path parameters use {braces}, not :colon (measured: 100% of this contract)'
    severity: error
    given: $.paths[*]~
    then:
      function: pattern
      functionOptions:
        notMatch: ':'
    x-pattern-key: 'Paths.{key}|pattern:!:'
  servers-https:
    description: 'Servers are https (measured: 100% of this contract)'
    severity: error
    given: $.servers[*].url
    then:
      function: pattern
      functionOptions:
        match: ^(https://|\{)
    x-pattern-key: Server.url|pattern:^(https://|\{)
  response-media-type:
    description: 'Responses are served as application/fhir+json (measured: 93% of this contract)'
    severity: warn
    given: $.paths[*][get,post,put,patch,delete].responses[*].content
    then:
      function: schema
      functionOptions:
        schema:
          type: object
          required:
          - application/fhir+json
    x-pattern-key: Response.content|schema:6bcf6b19
  info-has-description:
    description: 'The contract''s info block carries a description (measured: 100% of this contract)'
    severity: error
    given: $.info
    then:
      field: description
      function: truthy
    x-pattern-key: Info.description|present
  info-has-contact-or-terms:
    description: 'The contract''s info block names a contact or terms of service (measured: 100% of this contract)'
    severity: error
    given: $.info
    then:
      function: schema
      functionOptions:
        schema:
          anyOf:
          - required:
            - contact
          - required:
            - termsOfService
    x-pattern-key: OpenAPI.info|schema:093268bf
  info-title-present:
    description: 'Info declares title (measured: 100% of this contract)'
    severity: error
    given: $.info
    then:
      field: title
      function: defined
    x-pattern-key: Info.title|present
  info-title-min-length:
    description: 'Info.title runs at least 20 characters (measured: 100% of this contract)'
    severity: error
    given: $.info.title
    then:
      function: length
      functionOptions:
        min: 20
    x-pattern-key: Info.title|length
  info-description-present:
    description: 'Info declares description (measured: 100% of this contract)'
    severity: error
    given: $.info
    then:
      field: description
      function: defined
    x-pattern-key: Info.description|present
  info-description-min-length:
    description: 'Info.description runs at least 61 characters (measured: 100% of this contract)'
    severity: error
    given: $.info.description
    then:
      function: length
      functionOptions:
        min: 61
    x-pattern-key: Info.description|length
  info-termsofservice-https:
    description: 'Info.termsOfService is https (measured: 100% of this contract)'
    severity: error
    given: $.info.termsOfService
    then:
      function: pattern
      functionOptions:
        match: ^https://
    x-pattern-key: Info.termsOfService|pattern:^https://
  info-contact-present:
    description: 'Info declares contact (measured: 100% of this contract)'
    severity: error
    given: $.info
    then:
      field: contact
      function: defined
    x-pattern-key: Info.contact|present
  info-license-present:
    description: 'Info declares license (measured: 87% of this contract)'
    severity: info
    given: $.info
    then:
      field: license
      function: defined
    x-pattern-key: Info.license|present
  info-version-present:
    description: 'Info declares version (measured: 100% of this contract)'
    severity: error
    given: $.info
    then:
      field: version
      function: defined
    x-pattern-key: Info.version|present
  info-version-semver:
    description: 'info.version is numeric (measured: 100% of this contract)'
    severity: error
    given: $.info.version
    then:
      function: pattern
      functionOptions:
        match: ^v?\d+(\.\d+)*
    x-pattern-key: Info.version|pattern:^v?\d+(\.\d+)*
  contact-url-present:
    description: 'Contact declares url (measured: 100% of this contract)'
    severity: error
    given: $.info.contact
    then:
      field: url
      function: defined
    x-pattern-key: Contact.url|present
  contact-url-https:
    description: 'Contact.url is https (measured: 100% of this contract)'
    severity: error
    given: $.info.contact.url
    then:
      function: pattern
      functionOptions:
        match: ^https://
    x-pattern-key: Contact.url|pattern:^https://
  contact-email-present:
    description: 'Contact declares email (measured: 100% of this contract)'
    severity: error
    given: $.info.contact
    then:
      field: email
      function: defined
    x-pattern-key: Contact.email|present
  license-name-present:
    description: 'License declares name (measured: 100% of this contract)'
    severity: error
    given: $.info.license
    then:
      field: name
      function: defined
    x-pattern-key: License.name|present
  server-url-present:
    description: 'Server declares url (measured: 100% of this contract)'
    severity: error
    given: $.servers[*]
    then:
      field: url
      function: defined
    x-pattern-key: Server.url|present
  server-url-https:
    description: 'Server.url is https (measured: 100% of this contract)'
    severity: error
    given: $.servers[*].url
    then:
      function: pattern
      functionOptions:
        match: ^https://
    x-pattern-key: Server.url|pattern:^https://
  server-description-present:
    description: 'Server declares description (measured: 100% of this contract)'
    severity: error
    given: $.servers[*]
    then:
      field: description
      function: defined
    x-pattern-key: Server.description|present
  server-description-min-length:
    description: 'Server.description runs at least 10 characters (measured: 100% of this contract)'
    severity: error
    given: $.servers[*].description
    then:
      function: length
      functionOptions:
        min: 10
    x-pattern-key: Server.description|length
  tag-name-present:
    description: 'Tag declares name (measured: 100% of this contract)'
    severity: error
    given: $.tags[*]
    then:
      field: name
      function: defined
    x-pattern-key: Tag.name|present
  tag-name-casing-pascal:
    description: 'Tag.name is pascal case (measured: 100% of this contract)'
    severity: error
    given: $.tags[*].name
    then:
      function: pattern
      functionOptions:
        match: ^[A-Z][a-zA-Z0-9]*$
    x-pattern-key: Tag.name|pattern:^[A-Z][a-zA-Z0-9]*$
  operation-tags-present:
    description: 'Operation declares tags (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace]
    then:
      field: tags
      function: defined
    x-pattern-key: Operation.tags|present
  operation-summary-present:
    description: 'Operation declares summary (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace]
    then:
      field: summary
      function: defined
    x-pattern-key: Operation.summary|present
  operation-summary-min-length:
    description: 'Operation.summary runs at least 9 characters (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].summary
    then:
      function: length
      functionOptions:
        min: 9
    x-pattern-key: Operation.summary|length
  operation-description-min-length:
    description: 'Operation.description runs at least 343 characters (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].description
    then:
      function: length
      functionOptions:
        min: 343
    x-pattern-key: Operation.description|length
  operation-operationid-present:
    description: 'Operation declares operationId (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace]
    then:
      field: operationId
      function: defined
    x-pattern-key: Operation.operationId|present
  parameter-name-present:
    description: 'Parameter declares name (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*]
    then:
      field: name
      function: defined
    x-pattern-key: Parameter.name|present
  parameter-in-present:
    description: 'Parameter declares in (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*]
    then:
      field: in
      function: defined
    x-pattern-key: Parameter.in|present
  parameter-in-values:
    description: 'Parameter.in is one of query (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*].in
    then:
      function: enumeration
      functionOptions:
        values:
        - query
    x-pattern-key: Parameter.in|enum:query
  parameter-description-present:
    description: 'Parameter declares description (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*]
    then:
      field: description
      function: defined
    x-pattern-key: Parameter.description|present
  parameter-description-min-length:
    description: 'Parameter.description runs at least 47 characters (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*].description
    then:
      function: length
      functionOptions:
        min: 47
    x-pattern-key: Parameter.description|length
  parameter-required-present:
    description: 'Parameter declares required (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*]
    then:
      field: required
      function: defined
    x-pattern-key: Parameter.required|present
  parameter-schema-present:
    description: 'Parameter declares schema (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].parameters[*]
    then:
      field: schema
      function: defined
    x-pattern-key: Parameter.schema|present
  requestbody-content-present:
    description: 'RequestBody declares content (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].requestBody
    then:
      field: content
      function: defined
    x-pattern-key: RequestBody.content|present
  requestbody-required-present:
    description: 'RequestBody declares required (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].requestBody
    then:
      field: required
      function: defined
    x-pattern-key: RequestBody.required|present
  mediatype-schema-present:
    description: 'MediaType declares schema (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].responses[*].content[*]
    then:
      field: schema
      function: defined
    x-pattern-key: MediaType.schema|present
  response-description-present:
    description: 'Response declares description (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].responses[*]
    then:
      field: description
      function: defined
    x-pattern-key: Response.description|present
  response-description-min-length:
    description: 'Response.description runs at least 7 characters (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].responses[*].description
    then:
      function: length
      functionOptions:
        min: 7
    x-pattern-key: Response.description|length
  response-headers-present:
    description: 'Response declares headers (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].responses[*]
    then:
      field: headers
      function: defined
    x-pattern-key: Response.headers|present
  response-content-present:
    description: 'Response declares content (measured: 100% of this contract)'
    severity: error
    given: $.paths[*][get,put,post,delete,patch,options,head,trace].responses[*]
    then:
      field: content
      function: defined
    x-pattern-key: Response.content|present
  securityscheme-type-present:
    description: 'SecurityScheme declares type (measured: 100% of this contract)'
    severity: error
    given: $.components.securitySchemes[*]
    then:
      field: type
      function: defined
    x-pattern-key: SecurityScheme.type|present
  securityscheme-type-values:
    description: 'SecurityScheme.type is one of http (measured: 100% of this contract)'
    severity: error
    given: $.components.securitySchemes[*].type
    then:
      function: enumeration
      functionOptions:
        values:
        - http
    x-pattern-key: SecurityScheme.type|enum:http
  securityscheme-scheme-present:
    description: 'SecurityScheme declares scheme (measured: 100% of this contract)'
    severity: error
    given: $.components.securitySchemes[*]
    then:
      field: scheme
      function: defined
    x-pattern-key: SecurityScheme.scheme|present
  securityscheme-scheme-values:
    description: 'SecurityScheme.scheme is one of bearer (measured: 100% of this contract)'
    severity: error
    given: $.components.securitySchemes[*].scheme
    then:
      function: enumeration
      functionOptions:
        values:
        - bearer
    x-pattern-key: SecurityScheme.scheme|enum:bearer
  securityscheme-bearerformat-values:
    description: 'SecurityScheme.bearerFormat is one of JWT (measured: 100% of this contract)'
    severity: error
    given: $.components.securitySchemes[*].bearerFormat
    then:
      function: enumeration
      functionOptions:
        values:
        - JWT
    x-pattern-key: SecurityScheme.bearerFormat|enum:JWT

Work with this as data

Every ruleset here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for spectral rules

4 MCP tools reach this
  • find_rulesBrowse and filter every ruleset in the catalog.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
This ruleset 
curl "https://apis.io/api/v1/rules/nhs-digital-rules"
All spectral rules 
curl "https://apis.io/api/v1/rules?limit=25"

Calls without X-API-Key need no key. Calls with it need a paid plan — get a key.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.