api-specifications

Guidance for Splits Network REST API design, implementation, and documentation

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API Specifications Skill

This skill provides guidance for designing, implementing, and documenting REST APIs in the Splits Network platform.

Purpose

Help developers create consistent, well-documented REST APIs that follow Splits Network standards:

V2 Architecture: Standardized 5-route CRUD pattern
Response Format: Consistent { data, pagination } envelope
Access Control: Role-based filtering via shared access context
Event Publishing: Domain events for state changes
Documentation: Clear endpoint specs and examples

When to Use This Skill

Use this skill when:

Creating new REST API endpoints
Migrating V1 endpoints to V2 architecture
Documenting API contracts
Implementing pagination, filtering, or search
Adding validation or error handling
Publishing domain events

V2 API Architecture Standards

1. Standardized 5-Route Pattern

Every V2 resource follows this exact pattern:

// 1. LIST - Role-scoped collection
GET /api/v2/:resource?search=X&status=Y&sort_by=Z&page=1&limit=25
Response: { data: [...], pagination: { total, page, limit, total_pages } }

// 2. GET BY ID - Single resource
GET /api/v2/:resource/:id?include=related1,related2
Response: { data: {...} }

// 3. CREATE - New resource
POST /api/v2/:resource
Body: { field1: value1, field2: value2, ... }
Response: { data: {...} }

// 4. UPDATE - Single method handles ALL updates
PATCH /api/v2/:resource/:id
Body: { field1: newValue1, status: newStatus, ... }
Response: { data: {...} }

// 5. DELETE - Soft delete
DELETE /api/v2/:resource/:id
Response: { data: { message: 'Deleted successfully' } }

2. Response Format Standard

ALL responses MUST use the wrapped envelope:

// Success response
reply.send({ data: <payload> })

// List response with pagination
reply.send({
  data: [...],
  pagination: { total, page, limit, total_pages }
})

// Error response
reply.code(400).send({
  error: { code: "ERROR_CODE", message: "..." }
})

NEVER return unwrapped data: reply.send(payload) is incorrect.

3. Domain-Based Folder Structure

services/<service>/src/v2/
├── shared/                 # Shared V2 utilities
│   ├── events.ts           # EventPublisher class
│   ├── helpers.ts          # requireUserContext, validation
│   └── pagination.ts       # PaginationParams, PaginationResponse
├── <domain>/               # Domain folder (e.g., jobs, candidates)
│   ├── types.ts            # Domain-specific types
│   ├── repository.ts       # Data access with role-based filtering
│   └── service.ts          # Business logic, validation, events
└── routes.ts               # All V2 routes (imports from domains)

4. Repository Pattern with Access Context

import { resolveAccessContext } from "@splits-network/shared-access-context";

export class ResourceRepository {
    constructor(private supabase: SupabaseClient) {}

    async list(clerkUserId: string, filters: ResourceFilters) {
        const context = await resolveAccessContext(clerkUserId, this.supabase);

        const query = this.supabase.from("resources").select("*");

        // Apply role-based filtering from access context
        if (context.role === "recruiter") {
            query.eq("user_id", context.userId);
        } else if (context.role === "company_admin") {
            query.in("company_id", context.accessibleCompanyIds);
        }
        // Platform admins see everything (no filter)

        // Apply search/sorting filters
        if (filters.search) {
            query.ilike("name", `%${filters.search}%`);
        }
        if (filters.sort_by) {
            query.order(filters.sort_by, {
                ascending: filters.sort_order !== "desc",
            });
        }

        return query;
    }
}

5. Service Layer with Events

export class ResourceServiceV2 {
    constructor(
        private repository: ResourceRepository,
        private events: EventPublisher,
    ) {}

    async create(clerkUserId: string, data: ResourceCreate) {
        // Validate input
        this.validateResourceData(data);

        // Create via repository
        const resource = await this.repository.create(clerkUserId, data);

        // Publish event after successful creation
        await this.events.publish("resource.created", {
            resourceId: resource.id,
            createdBy: clerkUserId,
        });

        return resource;
    }

    async update(id: string, clerkUserId: string, updates: ResourceUpdate) {
        // Smart validation based on what's being updated
        if (updates.status) {
            this.validateStatusTransition(updates.status);
        }

        const updated = await this.repository.update(id, clerkUserId, updates);

        // Publish event
        await this.events.publish("resource.updated", {
            resourceId: id,
            changes: Object.keys(updates),
            updatedBy: clerkUserId,
        });

        return updated;
    }
}

6. Route Implementation

import { FastifyInstance } from "fastify";

export async function resourceRoutes(
    app: FastifyInstance,
    service: ResourceServiceV2,
) {
    // LIST
    app.get("/api/v2/resources", async (request, reply) => {
        const clerkUserId = request.headers["x-clerk-user-id"] as string;
        const {
            search,
            status,
            sort_by,
            sort_order,
            page = 1,
            limit = 25,
        } = request.query as any;

        const result = await service.list(clerkUserId, {
            search,
            status,
            sort_by,
            sort_order,
            page,
            limit,
        });

        return reply.send(result); // Service returns { data, pagination }
    });

    // GET BY ID
    app.get("/api/v2/resources/:id", async (request, reply) => {
        const clerkUserId = request.headers["x-clerk-user-id"] as string;
        const { id } = request.params as { id: string };
        const { include } = request.query as { include?: string };

        const resource = await service.getById(id, clerkUserId, include);
        return reply.send({ data: resource });
    });

    // CREATE
    app.post("/api/v2/resources", async (request, reply) => {
        const clerkUserId = request.headers["x-clerk-user-id"] as string;
        const data = request.body as ResourceCreate;

        const resource = await service.create(clerkUserId, data);
        return reply.code(201).send({ data: resource });
    });

    // UPDATE
    app.patch("/api/v2/resources/:id", async (request, reply) => {
        const clerkUserId = request.headers["x-clerk-user-id"] as string;
        const { id } = request.params as { id: string };
        const updates = request.body as ResourceUpdate;

        const resource = await service.update(id, clerkUserId, updates);
        return reply.send({ data: resource });
    });

    // DELETE
    app.delete("/api/v2/resources/:id", async (request, reply) => {
        const clerkUserId = request.headers["x-clerk-user-id"] as string;
        const { id } = request.params as { id: string };

        await service.delete(id, clerkUserId);
        return reply.send({ data: { message: "Deleted successfully" } });
    });
}

Query Parameters

List Endpoints

Standard query parameters for list endpoints:

interface StandardListParams {
    page?: number; // Page number (1-based)
    limit?: number; // Items per page (default 25, max 100)
    search?: string; // Search term (service-specific fields)
    sort_by?: string; // Field to sort by
    sort_order?: "asc" | "desc"; // Sort direction
    filters?: Record<string, any>; // Domain-specific filters
    include?: string; // Comma-separated related resources
}

Examples:

/api/v2/jobs?page=1&limit=25&search=engineer&status=active
/api/v2/applications?candidate_id=123&stage=screen&sort_by=created_at&sort_order=desc
/api/v2/candidates?include=documents,applications

Get By ID Endpoints

Support include parameter for related data:

// GET /api/v2/applications/:id?include=candidate,job,ai_review
if (includes.includes("candidate")) {
    application.candidate = await this.getCandidateData(
        application.candidate_id,
    );
}

Pagination

All list endpoints must return pagination metadata:

interface PaginationResponse {
  total: number;        // Total items across all pages
  page: number;         // Current page number (1-based)
  limit: number;        // Items per page
  total_pages: number;  // Total number of pages
}

// Example response
{
  "data": [...],
  "pagination": {
    "total": 1000,
    "page": 1,
    "limit": 25,
    "total_pages": 40
  }
}

Error Handling

Return structured error responses:

// 400 Bad Request - Validation error
reply.code(400).send({
    error: {
        code: "VALIDATION_ERROR",
        message: "Invalid input data",
        details: { field: "email", reason: "Invalid email format" },
    },
});

// 401 Unauthorized - Missing/invalid auth
reply.code(401).send({
    error: {
        code: "UNAUTHORIZED",
        message: "Authentication required",
    },
});

// 403 Forbidden - Insufficient permissions
reply.code(403).send({
    error: {
        code: "FORBIDDEN",
        message: "Insufficient permissions to access this resource",
    },
});

// 404 Not Found - Resource doesn't exist
reply.code(404).send({
    error: {
        code: "NOT_FOUND",
        message: "Resource not found",
        details: { resourceId: id },
    },
});

// 409 Conflict - Duplicate or constraint violation
reply.code(409).send({
    error: {
        code: "CONFLICT",
        message: "Resource already exists",
        details: { constraint: "unique_email" },
    },
});

// 500 Internal Server Error - Unexpected error
reply.code(500).send({
    error: {
        code: "INTERNAL_ERROR",
        message: "An unexpected error occurred",
    },
});

Event Publishing

Publish domain events for significant state changes:

// After successful create
await this.events.publish("resource.created", {
    resourceId: resource.id,
    companyId: resource.company_id,
    createdBy: clerkUserId,
});

// After successful update
await this.events.publish("resource.updated", {
    resourceId: id,
    changes: Object.keys(updates),
    updatedBy: clerkUserId,
});

// After successful delete
await this.events.publish("resource.deleted", {
    resourceId: id,
    deletedBy: clerkUserId,
});

// Domain-specific events
await this.events.publish("application.stage_changed", {
    applicationId: id,
    oldStage: oldStage,
    newStage: newStage,
    changedBy: clerkUserId,
});

API Documentation

Document each endpoint with:

Purpose: What the endpoint does
Path: Full path with parameters
Method: HTTP method (GET, POST, PATCH, DELETE)
Auth: Required authentication (Clerk JWT)
Access: Who can access (roles, scoping rules)
Query Params: Optional parameters
Request Body: Expected payload structure
Response: Success response format
Errors: Possible error codes and meanings
Example: Full request/response example

Example Documentation

### List Jobs

Returns a paginated list of jobs based on role-based access control.

**Endpoint**: `GET /api/v2/jobs`

**Authentication**: Required (Clerk JWT)

**Access Control**:

- **Recruiters**: See assigned jobs only
- **Company Users**: See jobs from their organization
- **Platform Admins**: See all jobs

**Query Parameters**:

- `page` (number, optional): Page number (default: 1)
- `limit` (number, optional): Items per page (default: 25, max: 100)
- `search` (string, optional): Search in job title
- `status` (string, optional): Filter by status (active, paused, closed)
- `company_id` (uuid, optional): Filter by company
- `sort_by` (string, optional): Sort field (created_at, title)
- `sort_order` (string, optional): Sort direction (asc, desc)

**Response**: `200 OK`

```json
{
    "data": [
        {
            "id": "123e4567-e89b-12d3-a456-426614174000",
            "title": "Senior Software Engineer",
            "company_id": "123e4567-e89b-12d3-a456-426614174001",
            "status": "active",
            "location": "San Francisco, CA",
            "created_at": "2026-01-13T10:00:00Z"
        }
    ],
    "pagination": {
        "total": 100,
        "page": 1,
        "limit": 25,
        "total_pages": 4
    }
}
```

Errors:

401 Unauthorized: Missing or invalid authentication
403 Forbidden: Insufficient permissions
500 Internal Server Error: Server error

Example Request:

curl -X GET "https://api.splits.network/api/v2/jobs?page=1&limit=25&status=active" \
  -H "Authorization: Bearer <clerk-jwt>"


## Common Patterns

### Current User Access Pattern

For user-specific singleton resources, use the `/me` alias pattern:

```typescript
// ✅ RECOMMENDED - Use /me alias on existing GET by ID endpoint
GET /api/v2/candidates/me
// Resolves to user's actual ID, returns { data: {...} }

// Implementation in route handler
app.get('/api/v2/candidates/:id', async (request, reply) => {
  const clerkUserId = request.headers['x-clerk-user-id'] as string;
  let { id } = request.params;

  // Resolve "me" to actual user ID
  if (id === 'me') {
    const context = await resolveAccessContext(clerkUserId, supabase);
    id = context.userId; // Actual UUID
  }

  // Standard getById logic - no special handling needed
  const candidate = await service.getById(id, clerkUserId);
  return reply.send({ data: candidate });
});

Benefits:

Intuitive: Clear what /me means
Performant: Direct ID lookup (not filtered list query)
Correct Shape: Returns { data: {...} } (singleton, not array)
No New Endpoint: Just an alias within existing GET by ID route
Still Secure: Access context validates user can access resolved ID

Single Update Method

One update method handles ALL updates with smart validation:

// ❌ WRONG - Multiple update endpoints
PATCH /api/v2/jobs/:id/status
PATCH /api/v2/jobs/:id/title
PATCH /api/v2/jobs/:id/close

// ✅ CORRECT - Single update endpoint
PATCH /api/v2/jobs/:id
Body: { status: "closed" } or { title: "New Title" } or any field

Include Parameters vs Child Endpoints

Use include parameters for related data, NOT child endpoints:

// ❌ WRONG - Child endpoints
GET /api/v2/applications/:id/documents
GET /api/v2/applications/:id/ai-review

// ✅ CORRECT - Include parameters
GET /api/v2/applications/:id?include=documents,ai_review
GET /api/v2/documents?application_id=:id
GET /api/v2/ai-reviews?application_id=:id

Data Enrichment with JOINs

Services share the same database (all tables in public schema) and can enrich data with JOINs:

// Enrich applications with candidate and job data
const enrichedApplications = await this.supabase.from("applications").select(`
    *,
    candidate:candidates(*),
    job:jobs(*),
    recruiter:recruiters(*)
  `);

// Note: All domain tables (applications, candidates, jobs, recruiters, etc.)
// are in the public schema. No cross-schema queries needed.

References

API Response Format: docs/guidance/api-response-format.md
Pagination Standard: docs/guidance/pagination.md
V2 Architecture Guide: docs/migration/v2/V2-ARCHITECTURE-IMPLEMENTATION-GUIDE.md
Service Architecture: docs/guidance/service-architecture-pattern.md
Access Context: packages/shared-access-context/README.md

Examples from Production

V2 Services:

Identity Service: services/identity-service/src/v2/
ATS Service: services/ats-service/src/v2/
Network Service: services/network-service/src/v2/
Billing Service: services/billing-service/src/v2/
Notification Service: services/notification-service/src/v2/

API Gateway Routes:

Gateway V2 Proxy: services/api-gateway/src/routes/v2/

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npx -y skills add https://github.com/diegosouzapw/awesome-omni-skill --skill api-specifications

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skills/development/api-specifications/SKILL.md