This is a conceptual architecture checklist. The GPA Calculator does not currently provide a public GPA-calculation API, API keys, sandbox, OpenAPI file, Postman collection, SDK, or embeddable widget.
The site does have unrelated content-search and OPT data routes. Do not mistake those for a public GPA calculation contract, and do not attempt to call examples from this article.
Decide whether a server API is appropriate
The existing GPA calculators run in the browser and store supported personal entries locally. Moving calculations or records to a server changes the privacy, security, operational, and legal boundary.
Before implementation, identify:
- the user and authority for every request;
- whether the service receives student records or only anonymous hypothetical inputs;
- the legal and contractual basis for processing;
- retention, access, disclosure, deletion, and incident-response rules;
- the benefit that requires a server rather than local calculation; and
- the failure and shutdown behavior.
If these decisions are unresolved, keep the calculation local.
Version the rule, not just the URL
A request must identify a named rule set with:
- owner and calculation purpose;
- effective period or cohort;
- course population;
- grade table and weighting eligibility;
- numerator and denominator rules;
- repeats and special marks;
- caps and precision; and
- source provenance and verification status.
Do not offer a universal percentage, international, or IB conversion preset. Return an unsupported-rule result when no authoritative version exists.
Define the calculation contract
For every operation, specify:
- input schema and units;
- required versus optional fields;
- identity and idempotency behavior;
- validation and unresolved-policy behavior;
- unrounded intermediate values;
- output status and evidence;
- error semantics; and
- compatibility guarantees.
The OpenAPI Specification can describe paths, operations, schemas, servers, and security requirements after the contract exists. It does not require a route such as /v1/gpa, noun-only paths, or any particular product feature.
Design errors from real behavior
HTTP specifications define the meaning of status codes, but the service must decide which condition occurred. Syntax problems, invalid content, missing authentication, denied authorization, and exhausted rate limits are different failures.
Publish and test a stable error object containing a machine-readable code, field pointer when appropriate, and non-sensitive explanation. If 429 is used, document retry behavior consistently with the implemented limiter. Do not label a value “impossible” until a verified rule set establishes the boundary.
Threat-model authentication and authorization
An API key or OAuth label does not create secure access by itself. Document data flows, actors, threats, issuer and audience checks, credential lifecycle, least-privilege authorization, revocation, and audit boundaries. If OAuth is selected, use the current OAuth security best practice.
Do not ingest education records until the actual deployment has undergone the applicable privacy and legal review. FERPA personally identifiable information can include direct and indirect identifiers; HTTPS and role names alone are not a compliance design.
Logs and analytics must exclude grades, course names, student identifiers, tokens, and full request bodies unless a separately reviewed operational need and policy explicitly allow them.
Specify reliability before batch features
Batch endpoints, asynchronous jobs, retries, caching, and idempotency keys are design options, not existing capabilities or universal requirements. Define acceptance tests for:
- single and batch arithmetic equivalence;
- partial failures;
- duplicate requests and conflicting IDs;
- concurrency and replay;
- timeouts and retry safety;
- privacy suppression and redaction;
- load and rate-limit behavior; and
- recovery after a rule-set change.
Choose limits from measured capacity and the actual data-risk model.
Publish documentation only after conformance tests
A real release should generate or validate its OpenAPI description against deployed behavior. Curl, JavaScript, Python, SDK, Postman, and sandbox examples should run as contract tests in the release pipeline.
Until then, avoid production-looking base URLs and credentials in conceptual documentation. The browser calculators are not a server-side oracle for external integrations.
Treat embedding as a separate product
There is no current iframe widget. Do not embed ordinary calculator routes as though they had a supported widget contract.
A future embed requires its own origin and message protocol, storage and analytics behavior, accessibility tests, privacy review, sizing contract, and failure states. CSP frame-ancestors can restrict permitted parents, but it is only one part of that boundary. “Read only” does not mean “stores no data.”
Plan compatible retirement
Choose a versioning and deprecation policy from actual service commitments. Path versioning is one option, not a standard requirement. If used, document compatibility, migration evidence, support windows, and observable retirement signals. RFC-defined Deprecation and Sunset headers can be part of that design after their semantics are implemented.
Release gate
Do not call the API or widget live until all of these exist and pass review:
- deployed calculation route and verified rule-set registry;
- threat model and privacy data-flow record;
- authentication and authorization tests;
- input, output, error, and idempotency contract tests;
- load, rate-limit, logging-redaction, and recovery tests;
- published OpenAPI artifact matching the deployment;
- tested examples and sandbox isolation;
- version and retirement policy; and
- public support and incident status process.
Frequently asked questions
What is the GPA API base URL?
There is none. This site does not currently offer a public GPA-calculation API.
Can I request an API key or use a sandbox?
No. No key issuance or sandbox exists.
Can I embed the current calculator in an iframe?
There is no supported widget contract. Do not treat the ordinary routes as an embeddable product.
Does this architecture support school records?
No implementation or compliance conclusion is claimed. That use case requires a concrete data flow, authority, contracts, security controls, and legal review before development.
Bottom line
An API document should describe tested deployed behavior. Until such a service exists, the responsible artifact is a preimplementation contract and threat-model checklist, not fictional endpoint documentation.