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Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-20 23:52:15 +09:00

6.1 KiB

id, title, category, status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, verification_status, tags, raw_sources, last_reinforced, github_commit, tech_stack
id title category status canonical_id aliases duplicate_of source_trust_level confidence_score verification_status tags raw_sources last_reinforced github_commit tech_stack
wiki-2026-0508-api-fundamentals API Fundamentals 10_Wiki/Topics verified self
API basics
REST GraphQL gRPC
Web API
none A 0.9 applied
api
rest
graphql
grpc
fundamentals
2026-05-10 pending
language framework
typescript REST/GraphQL/gRPC/tRPC

API Fundamentals

매 한 줄

"매 contract between systems — verbs, nouns, errors, evolution". 매 RPC (1980s, Sun RPC) → CORBA (1991) → SOAP (1998) → REST (Fielding 2000) → gRPC (2015) → GraphQL (2015) → tRPC (2020). 매 2026 modern stack 은 typed end-to-end (tRPC, GraphQL Codegen, gRPC + buf) + AsyncAPI 2.x for events.

매 핵심

매 four styles

  • REST: resource-oriented, HTTP verbs, stateless, cacheable. 매 public API standard.
  • GraphQL: client-specified queries, single endpoint, strong types. 매 BFF / mobile.
  • gRPC: binary (protobuf), HTTP/2, streaming, codegen. 매 internal, low-latency.
  • tRPC: TypeScript-first, no codegen, type inference. 매 Next.js / monorepo.

매 cross-cutting concerns

  • Versioning: URI (/v1), header (Accept-Version), or evolution (additive only).
  • Idempotency: idempotency key for unsafe verbs (POST). At-least-once → exactly-once at API.
  • Pagination: cursor (preferred) vs offset. 매 cursor 의 stable ordering.
  • Errors: RFC 7807 problem+json, gRPC status codes, GraphQL errors[].
  • Auth: OAuth2 / OIDC / mTLS / API key.

매 응용

  1. Public REST + GraphQL — Stripe (REST), GitHub (both), Shopify (GraphQL).
  2. Internal gRPC mesh — Google, Uber, Square.
  3. Full-stack tRPC — Vercel, Cal.com, T3 stack.

💻 패턴

REST resource design

GET    /orders?status=pending&cursor=abc123  → 200 [{...}], next_cursor
POST   /orders                                → 201 {id, ...}, Location
GET    /orders/{id}                           → 200 {...} | 404
PATCH  /orders/{id}  (JSON Merge Patch)       → 200 {...}
DELETE /orders/{id}                           → 204

REST idempotency

app.post("/orders", async (req, res) => {
  const idemKey = req.header("Idempotency-Key");
  const cached = await redis.get(`idem:${idemKey}`);
  if (cached) return res.status(200).json(JSON.parse(cached));

  const order = await createOrder(req.body);
  await redis.setex(`idem:${idemKey}`, 86400, JSON.stringify(order));
  res.status(201).json(order);
});

Cursor pagination

const limit = 50;
const rows = await db.query(
  `SELECT * FROM orders WHERE (created_at, id) < ($1, $2)
   ORDER BY created_at DESC, id DESC LIMIT $3`,
  [cursor.ts, cursor.id, limit + 1]
);
const hasMore = rows.length > limit;
const items = rows.slice(0, limit);
const nextCursor = hasMore ? encode(items.at(-1)) : null;

GraphQL schema + resolver

type Query {
  order(id: ID!): Order
  orders(first: Int!, after: String): OrderConnection!
}
type Order { id: ID!, status: OrderStatus!, items: [Item!]! }
type OrderConnection {
  edges: [OrderEdge!]!
  pageInfo: PageInfo!
}
const resolvers = {
  Query: {
    order: (_, {id}, ctx) => ctx.dataloaders.order.load(id),
    orders: async (_, {first, after}, ctx) => paginateOrders(first, after, ctx),
  },
  Order: {
    items: (order, _, ctx) => ctx.dataloaders.itemsByOrder.load(order.id),
  },
};

gRPC service (proto3)

syntax = "proto3";
package orders.v1;

service OrderService {
  rpc Get(GetRequest) returns (Order);
  rpc List(ListRequest) returns (stream Order);  // server streaming
  rpc Watch(WatchRequest) returns (stream OrderEvent);  // bidi-friendly
}
message Order {
  string id = 1;
  OrderStatus status = 2;
  google.protobuf.Timestamp created_at = 3;
}

tRPC procedure

import { router, publicProcedure } from "./trpc";
import { z } from "zod";

export const orderRouter = router({
  get: publicProcedure
    .input(z.object({ id: z.string() }))
    .query(({ input, ctx }) => ctx.db.order.findUnique({ where: { id: input.id } })),

  create: publicProcedure
    .input(z.object({ items: z.array(z.string()).min(1) }))
    .mutation(({ input, ctx }) => ctx.db.order.create({ data: { items: input.items } })),
});
// Client gets full type inference: trpc.order.get.useQuery({id}) typed

RFC 7807 error

{
  "type": "https://api.example.com/errors/insufficient-funds",
  "title": "Insufficient funds",
  "status": 402,
  "detail": "Account 12345 has balance $5, requested $50",
  "instance": "/orders/abc"
}

매 결정 기준

상황 Style
Public 3rd-party API REST + OpenAPI 3.1
Mobile/web with diverse query needs GraphQL
Internal microservices, low latency gRPC
TypeScript monorepo (Next.js) tRPC
Real-time bidirectional streams gRPC streaming or WebSocket
Async events AsyncAPI + Kafka/NATS

기본값: 매 REST + OpenAPI 의 public, 매 gRPC 의 internal, 매 tRPC 의 TS monorepo.

🔗 Graph

🤖 LLM 활용

언제: 매 cross-system contract 의 design, 매 client/server 매 separated, 매 versioned interface 필요. 언제 X: 매 internal function call (just call it), 매 single process, 매 < 100 lines glue script.

안티패턴

  • GET with side effects: 매 cache poisoning, 매 idempotency violation.
  • HTTP 200 with {error: ...} body: 매 status code semantics 의 ignore.
  • Versioning by minor change: 매 v1/v2/v3 explosion. 매 additive evolution 의 prefer.
  • Chatty API: 매 N+1 client roundtrips. 매 batch endpoint or GraphQL.
  • No pagination: 매 unbounded list → OOM at scale.

🧪 검증 / 중복

  • Verified (RFC 7231 HTTP, RFC 7807 problem+json, gRPC docs, GraphQL spec, tRPC docs).
  • 신뢰도 A.

🕓 Changelog

날짜 변경
2026-05-08 Phase 1
2026-05-10 Manual cleanup — full content (REST/GraphQL/gRPC/tRPC fundamentals)