Note: Stage 2: Draft — this spec is not yet official, but is now a fully formed solution. Drafts may continue to evolve and change, occasionally dramatically, and are not guaranteed to be accepted. Therefore, it is unwise to rely on a draft in a production GraphQL Service.
Introduction
This specification details how GraphQL should be served and consumed over HTTP in order to maximize interoperability between clients, servers and tools. This specification does not override or replace the GraphQL specification; it extends it to cover the topic of serving GraphQL services over HTTP. If any statement or algorithm in this specification appears to conflict with the GraphQL specification, the behavior detailed in the GraphQL specification should be used (and an issue raised).
The GraphQL specification deliberately does not specify the transport layer; however, HTTP is the most common choice when serving GraphQL to remote clients due to its ubiquity.
Copyright notice
Copyright © 2022-present, GraphQL contributors
THESE MATERIALS ARE PROVIDED “AS IS”. The parties expressly disclaim any warranties (express, implied, or otherwise), including implied warranties of merchantability, non-infringement, fitness for a particular purpose, or title, related to the materials. The entire risk as to implementing or otherwise using the materials is assumed by the implementer and user. IN NO EVENT WILL THE PARTIES BE LIABLE TO ANY OTHER PARTY FOR LOST PROFITS OR ANY FORM OF INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OF ANY CHARACTER FROM ANY CAUSES OF ACTION OF ANY KIND WITH RESPECT TO THIS DELIVERABLE OR ITS GOVERNING AGREEMENT, WHETHER BASED ON BREACH OF CONTRACT, TORT (INCLUDING NEGLIGENCE), OR OTHERWISE, AND WHETHER OR NOT THE OTHER MEMBER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Conformance
A conforming implementation of GraphQL over HTTP must fulfill all normative requirements. Conformance requirements are described in this document via both descriptive assertions and key words with clearly defined meanings.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in the normative portions of this document are to be interpreted as described in IETF RFC 2119. These key words may appear in lowercase and still retain their meaning unless explicitly declared as non-normative.
A conforming implementation of GraphQL over HTTP may provide additional functionality, but must not where explicitly disallowed or would otherwise result in non-conformance.
Non-Normative Portions
All contents of this document are normative except portions explicitly declared as non-normative.
Examples in this document are non-normative, and are presented to aid understanding of introduced concepts and the behavior of normative portions of the specification. Examples are either introduced explicitly in prose (e.g. "for example") or are set apart in example or counter-example blocks, like this:
This is an example of a non-normative example.
This is an example of a non-normative counter-example.
Notes in this document are non-normative, and are presented to clarify intent, draw attention to potential edge-cases and pit-falls, and answer common questions that arise during implementation. Notes are either introduced explicitly in prose (e.g. "Note: ") or are set apart in a note block, like this:
Note: This is an example of a non-normative note.
Though the GraphQL specification is transport agnostic, this GraphQL over HTTP specification aims to map GraphQL's semantics to their HTTP equivalents, enabling us to combine the full advantages of GraphQL with the rich feature set of HTTP.
GraphQL queries and mutations naturally mirror the request/response message model used in HTTP, allowing us to provide a GraphQL request in an HTTP request and a GraphQL response in an HTTP response.
:: In this document, the term server refers to a GraphQL over HTTP Specification compliant HTTP server unless the context indicates otherwise.
The role of a server is to provide a client access to one or more GraphQL services over HTTP. A server is not a GraphQL service; it is a GraphQL service host.
:: In this document, the term client refers to a GraphQL over HTTP Specification compliant HTTP client unless the context indicates otherwise.
The role of a client is to issue HTTP requests to a server in order to interact with a GraphQL service.
Note: GraphQL Subscriptions are beyond the scope of this specification at this time.
A server MUST enable GraphQL requests to one or more GraphQL schemas.
Each GraphQL schema a server provides MUST be served via one or more URLs.
A server MUST NOT require the client to use different URLs for different GraphQL query and mutation requests to the same GraphQL schema.
The GraphQL schema available via a single URL MAY be different for different clients. For example, alpha testers or authenticated users may have access to a schema with additional fields.
A server MAY forbid individual requests by a client to any endpoint for any
reason, for example to require authentication or payment; when doing so it
SHOULD use the relevant 4xx or 5xx status code. This decision SHOULD NOT be
based on the contents of a well-formed GraphQL-over-HTTP request.
Note: The server should not make authorization decisions based on any part of the GraphQL request; these decisions should be made by the GraphQL schema during GraphQL's ExecuteRequest(), allowing for a partial response to be generated.
Server URLs which enable GraphQL requests MAY also be used for other purposes, as long as they don't conflict with the server's responsibility to handle GraphQL requests.
It is RECOMMENDED to end the path component of the URL with /graphql, for
example:
http://example.com/graphqlhttp://product.example.com/graphqlhttp://example.com/product/graphqlServers and clients MUST support JSON as a serialization format.
The following are the officially recognized GraphQL media types:
| Name | Description |
|---|---|
application/json |
Media type for GraphQL JSON requests |
application/graphql-response+json |
Media type for GraphQL JSON responses |
For details of the shapes of these JSON payloads, please see Request and Response.
If the media type in a Content-Type or Accept header does not include
encoding information and matches one of the officially recognized GraphQL media
types, then utf-8 MUST be assumed (e.g. for header
Content-Type: application/graphql-response+json, UTF-8 encoding would be
assumed).
A server MUST accept POST requests, and MAY accept other HTTP methods, such as GET.
:: A GraphQL-over-HTTP request is an HTTP request that encodes the following parameters in one of the manners described in this specification:
- {query} - (Required, string): The string representation of the Source Text of a GraphQL Document as specified in the Language section of the GraphQL specification.
- {operationName} - (Optional, string): The name of the Operation in the Document to execute.
- {variables} - (Optional, map): Values for any Variables defined by the Operation.
- {extensions} - (Optional, map): This entry is reserved for implementers to extend the protocol however they see fit, as specified in the Response section of the GraphQL specification.
Servers receiving a request with additional properties MUST ignore properties they do not understand.
If implementers need to add additional information to a request they MUST do so via other means; the RECOMMENDED approach is to add an implementer-scoped entry to the {extensions} object.
Note: When comparing GraphQL-over-HTTP request against the term "request" in the GraphQL specification you should note the GraphQL schema and "initial value" are not included in the GraphQL-over-HTTP request; they are handled by the server based on the URL used.
Note: Be aware that query is a misleading parameter name as its value is a
string describing one or more operations, each of which may be a query or
mutation. A better name would have been document, but the term query is well
established.
Note: So long as it is a string, {query} does not have to parse or validate to be part of a well-formed GraphQL-over-HTTP request.
A client MUST indicate the media types that it supports in responses using the
Accept HTTP header as specified in
RFC7231.
The client MUST include the media type application/graphql-response+json in
the Accept header.
For HTTP GET requests, the GraphQL-over-HTTP request parameters MUST be
provided in the query component of the request URL, encoded in the
application/x-www-form-urlencoded format as specified by the
WHATWG URLSearchParams class.
The {query} parameter MUST be the string representation of the source text of the document as specified in the Language section of the GraphQL specification.
The {operationName} parameter, if present and not the empty string, MUST be a string.
Each of the {variables} and {extensions} parameters, if present, MUST be encoded as a JSON object string.
For robustness, specifying the empty string for optional request parameters is equivalent to not specifying them at all.
The {operationName} parameter, if present and not the empty string, represents the name of the operation to be executed within the {query} as a string.
GET requests MUST NOT be used for executing mutation operations. This restriction is necessary to conform with the long-established semantics of safe methods within HTTP.
Note: In the final URL all of these parameters will appear in the query component of the request URL as URL-encoded values due to the WHATWG URLSearchParams encoding specified above.
Note: By the above, operationName=null represents an operation with the name
"null" (such as query null { __typename }).
If we wanted to execute the following GraphQL query:
query($id: ID!){user(id:$id){name}}
With the following query variables:
{"id":"QVBJcy5ndXJ1"}
This request could be sent via an HTTP GET as follows:
http://example.com/graphql?query=query(%24id%3A%20ID!)%7Buser(id%3A%24id)%7Bname%7D%7D&variables=%7B%22id%22%3A%22QVBJcy5ndXJ1%22%7DAn empty {operationName} is allowed. This is a valid request:
http://example.com/graphql?query=%7B%20foo%20%7D&operationName=A GraphQL POST request MUST have a body which contains values of the
GraphQL-over-HTTP request parameters encoded using the application/json
media type.
The {query} parameter MUST be the string representation of the source text of the document as specified in the Language section of the GraphQL specification.
The {operationName} parameter, if present and not null, MUST be a string.
Each of the {variables} and {extensions} parameters, if present and not null, MUST be a JSON object.
For robustness, specifying null for optional request parameters is equivalent to not specifying them at all.
A client MUST indicate the media type of a request body using the Content-Type
header as specified in RFC7231.
A server MUST support POST requests encoded with the application/json media
type (as indicated by the Content-Type header) encoded with UTF-8.
For POST requests using an officially recognized GraphQL Content-Type without
indicating an encoding, the server MUST assume the encoding is utf-8.
If the client does not supply a Content-Type header with a POST request, the
server SHOULD reject the request using the appropriate 4xx status code.
If the values of {query} and {operationName} indicate that a mutation operation
is to be executed with a GET request, the server MUST respond with error status
code 405 (Method Not Allowed) and halt execution.
Note: Rejecting such requests encourages clients to supply a Content-Type
header with every POST request. A server has the option to assume any media type
they wish when none is supplied, with the understanding that parsing the request
may fail.
If we wanted to execute the following GraphQL query:
query ($id: ID!) {
user(id: $id) {
name
}
}
With the following query variables:
{
"id": "QVBJcy5ndXJ1"
}This request could be sent via an HTTP POST to the relevant URL using the JSON encoding with the headers:
Content-Type: application/json
Accept: application/graphql-response+json
And the body:
{
"query": "query ($id: ID!) {\n user(id: $id) {\n name\n }\n}",
"variables": {
"id": "QVBJcy5ndXJ1"
}
}When a server receives a well-formed GraphQL-over-HTTP request, it must return a well‐formed GraphQL response. The server's response describes the result of validating and executing the requested operation if successful and describes any errors encountered during the request.
A server must comply with RFC7231.
The body of the server's response MUST follow the requirements for a GraphQL response, encoded directly in the chosen media type.
If an Accept header is provided, the server MUST respect the given Accept
header and attempt to encode the response in the highest priority media type
listed that is supported by the server.
A server MUST support responses using the application/graphql-response+json
media type.
A server MAY additionally support other response media types.
A server MUST indicate the media type of the response with a Content-Type
header, and SHOULD indicate the encoding (e.g.
application/graphql-response+json; charset=utf-8).
In alignment with the
HTTP 1.1 Accept
specification, when a client does not include at least one supported media type
in the Accept HTTP header, the server MUST either:
- Respond with a
406 Not Acceptablestatus code and stop processing the request (RECOMMENDED); OR - Disregard the
Acceptheader and respond with the server's choice of media type (NOT RECOMMENDED).
Note: It is unlikely that a client can process a response that does not match
one of the media types it has requested, hence 406 Not Acceptable being the
recommended response. However, the server authors may know better about the
specific clients consuming their endpoint, thus both approaches are permitted.
Validation of a well-formed GraphQL-over-HTTP request SHOULD apply all the validation rules specified by the GraphQL specification.
The server MAY, at its discretion, apply additional validation rules.
Note: Examples of additional validation rules the server may apply include depth limit, complexity limit, etc.
Execution of a GraphQL-over-HTTP request follows GraphQL's ExecuteRequest() algorithm.
Note: In general, a GraphQL-over-HTTP request that does not pass validation should not be executed; however in certain circumstances, for example persisted operations that were previously known to be valid, the server may attempt execution regardless of validation errors.
In case of errors that completely prevent the generation of a well-formed
GraphQL response, the server MUST respond with the appropriate status code
depending on the concrete error condition, and MUST NOT respond with a 2xx
status code.
Note: Typically the appropriate status code will be 400 (Bad Request).
If the GraphQL response contains the {data} entry and it is not {null}, then
the server MUST reply with a 2xx status code.
Note: The result of executing a GraphQL operation may contain partial data as well as encountered errors. Errors that happen during execution of the GraphQL operation typically become part of the result, as long as the server is still able to produce a well-formed GraphQL response. There's currently not an approved HTTP status code to use for a "partial response," contenders include WebDAV's status code "207 Multi-Status" and using a custom code such as "247 Partial Success." IETF RFC2616 Section 6.1.1 states "codes are fully defined in section 10" implying that though more codes are expected to be supported over time, valid codes must be present in this document.
If the GraphQL response contains the {data} entry and it is {null}, then the
server SHOULD reply with a 2xx status code.
Note: Using 4xx and 5xx status codes in this situation is not recommended -
since no GraphQL request error has occurred it is seen as a "partial
response". This is typically the case if an error is propagated to the root
field.
If the GraphQL response does not contain the {data} entry then the server MUST
reply with a 4xx or 5xx status code as appropriate.
Note: The GraphQL specification indicates that the only situation in which the GraphQL response does not include the {data} entry is one in which the {errors} entry is populated.
If the request is not a well-formed GraphQL-over-HTTP request, or it does not
pass validation, then the server SHOULD reply with 400 status code.
If the client is not permitted to issue the GraphQL request then the server
SHOULD reply with 403, 401 or similar appropriate status code.
The following examples provide guidance on how to deal with specific error cases:
For example a POST request body of NONSENSE or {"query": (note: invalid
JSON).
Requests that the server cannot interpret should result in status code 400
(Bad Request).
For example a POST request body of {"qeury": "{__typename}"} (note: typo) or
{"query": "query Q ($i:Int!) { q(i: $i) }", "variables": [7]} (note: invalid
shape for variables).
A request that does not constitute a well-formed GraphQL-over-HTTP request
SHOULD result in status code 400 (Bad Request).
For example a POST request body of {"query": "{"}.
Requests where the GraphQL document cannot be parsed should result in status
code 400 (Bad Request).
If a request fails GraphQL validation, the server SHOULD return a status code
of 400 (Bad Request) without proceeding to GraphQL execution.
If GetOperation() raises a
GraphQL request error, the server SHOULD NOT execute the request and SHOULD
return a status code of 400 (Bad Request).
If
CoerceVariableValues()
raises a GraphQL request error, the server SHOULD NOT execute the request and
SHOULD return a status code of 400 (Bad Request).
If the operation is executed and no GraphQL request error is raised then the
server SHOULD respond with a status code of 200 (Okay). This is the case even
if a GraphQL field error is raised during
GraphQL's ExecuteQuery() or
GraphQL's ExecuteMutation().
Note: The GraphQL specification differentiates field errors from request errors and refers to the situation wherein a GraphQL field error occurs as a partial response; it still indicates successful execution.
This section of the specification is non-normative, even where the words and phrases specified in RFC2119 are used.
Previous to this specification, the article Serving over HTTP (WayBack Machine entry, 1st June 2022) on the graphql.org website served as guidance.
This article used application/json as media type for the response.
In some cases, the response received by a client may not originate from a
GraphQL service, but instead from an intermediary—such as an API gateway, proxy,
firewall or other middleware—that does not implement this specification. Such an
intermediary might produce the response to indicate an error, returning a
response with 4xx or 5xx status code and potentially using the standard
application/json media type to encode the reason for the error. Such a
response is unlikely to be a valid GraphQL response.
For this reason, a client application receiving an application/json response,
could rely on the response being a well-formed GraphQL response only if the
status code is 200.
This caused multiple observability issues because it was challenging to distinguish a well-formed GraphQL response from an intermediary response.
application/graphql-response+json allows to distringuish a well-formed
GraphQL response from another intermediary response and is the required media
type moving forward.
For compatibility reasons, clients and servers may support application/json as
described in this section.
Note: Servers may wish to only support the application/graphql-response+json
media type so that related HTTP tooling may utilize the HTTP status codes of
responses without having to be GraphQL-aware.
To maximize compatibility, a client may include the media type
application/json in the Accept header. When doing this, it is recommended
that the client set the Accept header to
application/graphql-response+json, application/json;q=0.9.
Note: The q=0.9 parameter tells content negotiation that application/json
should only be used if application/graphql-response+json is not supported.
When using the application/json media type, the server should use the 200
status code for every response to a well-formed GraphQL-over-HTTP request,
independent of any GraphQL request error or GraphQL field error raised.
If the response uses a non-200 status code then the client must not rely on
the body to be a well-formed GraphQL response.
If the GraphQL response contains a non-null {data} entry then the server must
use the 200 status code.
Note: This indicates that no GraphQL request error was raised, though one or more GraphQL field error may have been raised this is still a successful execution - see "partial response" in the GraphQL specification.
The server should not use a 4xx or 5xx status code for a response to a
well-formed GraphQL-over-HTTP request.
If the URL is not used for other purposes, the server should use a 4xx status
code to respond to a request that is not a well-formed GraphQL-over-HTTP
request.
This specification focuses solely on the intersection of GraphQL and HTTP. General concerns of either technology, including security concerns, are out of scope, except where their interaction introduces additional considerations.
Implementers are expected to have a solid understanding of the security
implications of exposing a service over HTTP, and are responsible for
implementing relevant mitigations and solutions. This specification will not
repeat standard HTTP best practices such as not using GET for requests with
side effects, safe logging of requests without revealing sensitive information,
ensuring all connections are encrypted via HTTPS, placing limits on the length
of incoming data, implementing rate limits, authorization and authentication
security, request tracing, intrusion detection, and so on.
Implementers are further expected to have a solid understanding of the security implications of running a GraphQL service and are responsible for implementing relevant mitigations and solutions there. For example, they may: limit the size and token count of GraphQL documents; ensure document validity; limit the number of errors a response may return; limit information revealed via errors; enforce validation and execution timeouts and pagination limits; implement query depth and complexity limits; implement authentication and authorization; apply rate limits to critical logic; and so on.
Where this specification leaves flexibility for the implementer, the implementer should be very cautious when exercising this freedom. Implementers must make themselves aware of and account for the security implications of their choices; while many alternative choices can be secured, securing them is outside of the scope of this specification.
For example, this specification allows alternative media types to be used to
encode the request body; however, media types such as multipart/form-data or
application/x-www-form-urlencoded may result in the request being treated by a
browser as a "simple request", which does not require a "preflight", thereby
opening the server up to Cross-Site Request Forgery (CSRF/XSRF) attacks. The
recommended application/json media type requires a "preflight" check when
issued cross-domain. See
CORS protocol in the WHATWG
Fetch spec for more details on this.
Note: One approach used by the community to mitigate CSRF risks is to ensure a
request is not "simple" by requiring a custom header—such as
GraphQL-Require-Preflight—is included. The presence of a custom header forces
browsers to enact a "preflight" check, thereby adding an additional layer of
security. (This is not a standard header, and many alternative headers could
serve the same purpose. This is presented merely as an example of a pattern seen
in the community.)
Further extending this example, using multipart/form-data may allow large
values to be referenced multiple times in a GraphQL operation, potentially
causing the GraphQL service to process a much larger GraphQL request than the
HTTP request size would suggest.
For more detailed security considerations, please refer to RFC 7231, RFC 6454, other relevant RFCs, and other resources such as OWASP.
Supporting formats not described by this specification may have potential conflicts with future versions of this specification as ongoing development aims to standardize and ensure the security and interoperability of GraphQL over HTTP whilst accounting for its growing feature set. For this reason, it is recommended to adhere to the officially recognized formats outlined here.