`User.glucoseUnit` has existed since v1.2 and around thirty surfaces read it — the dashboard tiles, the glucose page, the targets panel, the CSV and FHIR exports, the doctor report, the Coach snapshot, the low-reading push copy. Nothing could ever write it. No route, no schema, no field on any form, so every account resolved to the mg/dL default and the mmol/L half of the app was unreachable code. Anyone who reads glucose in mmol/L converted in their head on every screen. This is the missing end: a `GET`/`PATCH /api/auth/me/glucose-unit` scalar on the pattern the unit-preference endpoint next door established, and a dropdown in the profile form beside it. Deliberately its own control rather than a branch of metric/imperial: metric countries are split on which unit they read glucose in, so one dropdown would get half of them wrong. Storage is untouched and stays untouched. Every reading is written in mg/dL by every ingest path and the unit only selects a display branch, so nothing already recorded is reinterpreted. The entry form moved with the preference, which is the half that could have hurt: it asks in the chosen unit and inverts through `toCanonicalMgdl` on submit, so a 5.3 typed by an mmol/L reader is filed as 95 mg/dL rather than as 5.3 — a value the plausibility band accepts in silence and every surface reads back as a severe hypo. The contract gains the endpoint and nothing else; the account payload already carried the field.
HealthLog API Spec
openapi.yaml is the OpenAPI 3.1 description for the HealthLog
Next.js API and the source of truth for the native iOS client's DTO
codegen. The file is generated: pnpm openapi:generate emits it
from the Zod registry under src/lib/openapi/ (registry.ts plus the
route modules in src/lib/openapi/routes/). Do not edit the YAML by
hand; the next generation overwrites it, and CI (openapi:check)
fails the build when the committed YAML drifts from the registry.
The MCP server is documented separately — it is a distinct contract over JSON-RPC, not part of the REST OpenAPI spec:
mcp-capabilities.md— the tool, resource, and prompt catalogue, the grounding contract, and the write model.mcp-skills.md— building a connector or skill on top of it.../self-hosting/mcp.md— enabling and connecting the surface (operator guide).
Preview locally
Open an interactive Redoc preview in your browser:
npx @redocly/cli preview docs/api/openapi.yaml
Generate static HTML for sharing:
npx @redocly/cli build-docs docs/api/openapi.yaml --output docs/api/index.html
Validate
npx @redocly/cli lint docs/api/openapi.yaml
The spec is expected to be lint-clean (errors = 0). Warnings such as
no-server-example.com for the localhost dev server are tolerated;
re-run the lint to see what it produces against the current file
before treating a warning as a regression.
Layout
info— title, description, andversionmirrored automatically frompackage.jsonat generation time. Never bump it by hand.servers—https://healthlog.example.comas the self-hosted placeholder plushttp://localhost:3000for local development.tags— domain groupings; the current set lives at the top of the generated file (Auth,Measurements,Medications,Mood,Analytics,Insights,Consent,Dashboard,Notifications,Devices,Export,Sync,Cycle,MeasurementReminders,Labs,Illness,Documents,Records,Admin,Meta,Retired).securitySchemes:-
bearerAuth—hlk_*API tokens. A scope grants what it names and nothing adjacent, so where a token comes from decides what it reaches:- a completed password / passkey / refresh exchange mints the
cookie-equivalent
["*"]token the native client carries; - a medication's own API-endpoint toggle mints
medication:ingestplusmedication:<id>:ingest, the pair/api/ingest/medicationgates on; POST /api/mcp/tokensmintshealth:read(optionally plushealth:write), audience-bound to/mcpand refused on REST writes;POST /api/tokens/measurementsmintsmeasurements:write, accepted byPOST /api/measurementsandPOST /api/measurements/batchonly, on the holder's own record only.
POST /api/tokensis not among them — that generic mint was removed in v1.30.17. The path still lists (GET) and revokes (DELETE /api/tokens/{id}) every token above, whichever surface issued it. - a completed password / passkey / refresh exchange mints the
cookie-equivalent
-
sessionCookie— HttpOnlyhealthlog_sessioncookie set by the password and passkey login flows. Used by the web app and any iOS client running inside a web view.
-
components.schemas— DTOs for the documented routes plus the underlying Prisma models (e.g.Measurement,Medication,MedicationIntakeEvent,MoodEntry,User,DashboardLayout,ApiEnvelope,ApiError).paths— the client-facing REST surface. Not everysrc/app/api/**/route.tsis in the contract: most/api/admin/*routes, the OAuth connect/callback legs, and the webhook surfaces are not documented here. TheRetiredtag lists removed paths that answer410 Gone.
Conventions
- Successful responses use the envelope
{ data, error: null }. - Error responses use the envelope
{ data: null, error: '<message>' }. - Pagination uses
limit+offsetquery parameters and ameta: { total, limit, offset }block on the response. - All timestamps are ISO 8601 / RFC 3339 (
format: date-time) in UTC. - IDs are CUIDs (opaque strings).
Updating the spec
When adding or changing routes:
- Update the relevant route handler under
src/app/api/**/route.ts. - Change the Zod schemas and their
.meta()registrations undersrc/lib/openapi/(registry entry plus the matching module insrc/lib/openapi/routes/). KeepoperationIdcamelCase and stable; the iOS codegen keys off it. - Run
pnpm openapi:generateand commit the regeneratedopenapi.yamlalongside the schema change. CI'sopenapi:checkfails on drift. - Never edit the YAML directly and never bump
info.versionby hand; the version followspackage.jsonat generation time.