parashield-backend

NestJS API server for Parashield — a decentralized parametric insurance protocol on Stellar Soroban.

Two responsibilities: serve the REST API consumed by the frontend, and run the keeper daemon that submits oracle data and triggers claims automatically.

Architecture

ParaShield backend is built around four modules:

Module	Role
Policy Engine (`src/policy/`)	Product catalog, policy purchase, premium calculation, coverage validation
Claims Processor (`src/claims/`)	Manual and automatic claim submission, duplicate claim prevention, claim history
Oracle Worker (`src/oracle/`)	Fetches real-world data (rainfall, temperature, flight delays) from external APIs and persists to DB
Stellar Bridge (`src/stellar/`)	Builds, simulates, and submits Soroban transactions. Manages the keeper keypair

Supporting infrastructure:

PrismaService — PostgreSQL integration for policy and oracle data storage
AuthModule — Stellar wallet signature verification + JWT issuance
LoggingInterceptor — Request/response duration logging
ThrottleGuard — IP-based rate limiting (60 req/min)
Vault bootstrap — optional HashiCorp Vault KV loading before Nest validates env vars
OpenTelemetry — optional distributed tracing when OTEL packages are installed/configured

Authentication

ParaShield supports two authentication schemes:

JWT bearer auth: the primary frontend flow. Clients request /api/v1/auth/challenge, sign the nonce, call /api/v1/auth/login, then send Authorization: Bearer <token>. JwtAuthGuard verifies the token and sets req.wallet from the token payload.
Wallet-header auth: a legacy request-signature flow for protected API routes. Clients send x-wallet-address, x-wallet-message, and x-wallet-signature; AuthMiddleware verifies the Stellar signature and sets req.wallet.

Operator-only oracle fetch endpoints require either x-api-key: <ORACLE_OPERATOR_API_KEY> or an admin JWT. Public endpoints such as /api/v1/products, /api/v1/oracle/latest/:key, /api/v1/health, and /docs do not run wallet-header middleware.

API key rotation

Operator/admin API keys can be rotated without downtime:

Set the new key on ORACLE_OPERATOR_API_KEY (or ADMIN_API_KEY) and move the outgoing key to ORACLE_OPERATOR_API_KEY_PREVIOUS (or ADMIN_API_KEY_PREVIOUS), then restart.
Both keys authenticate during the grace window — requests using the old key are logged as warnings.
Once all clients have migrated, remove the *_PREVIOUS variables.

The overlap is bounded by API_KEY_ROTATION_GRACE_MINUTES (default 1440 = 24 hours, measured from process start). Setting it to 0 disables previous keys immediately.

API Endpoints

All endpoints are prefixed with /api/v1. Swagger docs available at /docs.

Policy

Method	Route	Description
`GET`	`/api/v1/products`	List all active insurance products
`GET`	`/api/v1/policies/me?wallet=<address>`	Get policies for a wallet address
`GET`	`/api/v1/policies/:id`	Get a single policy by UUID
`POST`	`/api/v1/policies/buy`	Calculate premium and get a purchase quote

Claims

Method	Route	Description
`POST`	`/api/v1/claims/submit`	Submit a manual claim
`POST`	`/api/v1/claims/:policyId/auto`	Trigger automatic claim evaluation (keeper only)
`GET`	`/api/v1/claims/:id`	Get claim details by ID
`GET`	`/api/v1/claims/history/:wallet`	Get all claims for a wallet address

Oracle

Method	Route	Description
`GET`	`/api/v1/oracle/latest/:key`	Get the latest reading for an oracle key
`POST`	`/api/v1/oracle/fetch/rainfall`	Operator-only: fetch rainfall data from Open-Meteo
`POST`	`/api/v1/oracle/fetch/temperature`	Operator-only: fetch temperature data from Open-Meteo
`GET`	`/api/v1/oracle/rainfall`	Legacy: fetch rainfall via query params
`GET`	`/api/v1/oracle/flight`	Fetch flight delay from AviationStack

Auth & Health

Method	Route	Description
`POST`	`/api/v1/auth/login`	Verify Stellar wallet signature and issue JWT
`GET`	`/api/v1/health`	Service health check (includes DB ping)

All responses follow the shape: { success: boolean, data?: any, error?: string }. Values are returned in 7-decimal fixed point as strings (matching Stellar asset precision).

Local Setup

# 1. Clone and install dependencies
git clone <repo-url>
cd parashield-backend
npm install

# 2. Start PostgreSQL and Redis via Docker
docker-compose up -d

# 3. Configure environment
cp .env.example .env
# Edit .env with your KEEPER_SECRET_KEY and contract addresses

# 4. Run database migrations
npx prisma migrate dev

# 5. Start in development mode
npm run start:dev

The API will be available at http://localhost:3001/api/v1. Swagger docs at http://localhost:3001/docs.

Production build

npm run build
npm run start:prod

CORS configuration

CORS is enabled in src/main.ts and controlled entirely via environment variables (see .env.example):

Variable	Required	Default	Description
`CORS_ORIGIN`	Yes	—	Allowed origin(s). Single origin or comma-separated list, e.g. `https://app.example.com,https://staging.example.com`. The server refuses to start without it. Wildcards (`*`) are not accepted — production must name explicit domains.
`CORS_METHODS`	No	`GET,POST,PUT,DELETE,OPTIONS`	Comma-separated list of allowed HTTP methods.
`CORS_ALLOWED_HEADERS`	No	`Content-Type,Authorization,x-wallet-address,x-wallet-signature,x-wallet-message,x-api-key,x-admin-api-key`	Comma-separated list of allowed request headers.
`CORS_CREDENTIALS`	No	`false`	Set to `true` to send `Access-Control-Allow-Credentials` (needed only for cookie-based clients; the API itself authenticates via headers).

The defaults reproduce the previously hardcoded configuration, so no behavior changes unless the variables are set.

Production CORS example

# .env (production)
CORS_ORIGIN=https://app.parashield.io,https://staging.parashield.io

Multiple origins are comma-separated. The server logs the active origin list at startup so you can confirm the value was parsed correctly.

Error handling

All error responses follow the same envelope shape regardless of endpoint:

{
  "success": false,
  "errorCode": "NOT_FOUND",
  "error": "Policy not found",
  "statusCode": 404,
  "path": "/api/v1/policies/abc123",
  "timestamp": "2024-01-15T10:30:00.000Z"
}

Field	Type	Description
`success`	`boolean`	Always `false` for errors.
`errorCode`	`string`	Stable machine-readable code (see table below). Key off this, not `error`.
`error`	`string` \| `object`	Human-readable message, or NestJS validation error details for 400s. May change between versions.
`statusCode`	`number`	Mirrors the HTTP status code.
`path`	`string`	The request path that produced the error.
`timestamp`	`string`	ISO-8601 UTC timestamp.

Error codes

`errorCode`	HTTP status	When it occurs
`VALIDATION_ERROR`	400	Request body fails class-validator rules (missing/invalid fields, wrong types). The `error` field contains an array of violation objects.
`UNAUTHORIZED`	401	Missing or invalid JWT / wallet signature. Include `Authorization: Bearer <token>` or valid wallet headers.
`FORBIDDEN`	403	Authenticated but not allowed (e.g. accessing another wallet's policy, calling an operator-only endpoint without an API key).
`NOT_FOUND`	404	Resource does not exist (policy ID, claim ID, oracle key, etc.).
`CONFLICT`	409	Duplicate resource (e.g. submitting a claim when one is already active for the same policy).
`GONE`	410	Resource existed but is no longer accessible (e.g. an expired policy).
`TOO_MANY_REQUESTS`	429	Rate limit exceeded (60 requests per minute per IP). Back off and retry after the `Retry-After` header value.
`SERVICE_UNAVAILABLE`	503	Downstream dependency unavailable (database, Redis, Stellar RPC).
`BAD_REQUEST`	400	Generic bad request not covered by validation (malformed path param, unsupported value, etc.).
`INTERNAL_ERROR`	500	Unexpected server-side failure. The error is logged server-side; the response body intentionally omits internal details.

Handling validation errors (400)

When class-validator rejects a request body the error field is an array of NestJS constraint objects:

{
  "success": false,
  "errorCode": "VALIDATION_ERROR",
  "error": {
    "message": ["wallet must be a string", "productId should not be empty"],
    "error": "Bad Request",
    "statusCode": 400
  },
  "statusCode": 400,
  "path": "/api/v1/policies/buy",
  "timestamp": "2024-01-15T10:30:00.000Z"
}

Check each entry in error.message for the field name and violated constraint.

Rate limiting (429)

The global throttle allows 60 requests per minute per IP. When exceeded the response includes a Retry-After header with the number of seconds until the window resets. Clients should respect this header rather than retrying immediately. Successful responses from guarded routes also include:

X-RateLimit-Limit
X-RateLimit-Remaining
X-RateLimit-Reset

Those values let clients and gateways track quota without waiting for a 429.

Secrets management

If you want to source secrets from HashiCorp Vault instead of environment variables, set:

VAULT_ADDR
VAULT_TOKEN
VAULT_KV_PATH

When all three are present, the server fetches the KV secret before Nest bootstraps and merges the returned key/value pairs into process.env. The Vault payload should use the standard KV v2 shape (data.data).

OpenTelemetry tracing

Tracing is enabled when the OpenTelemetry packages are installed and the following variables are set:

OTEL_SERVICE_NAME
OTEL_EXPORTER_OTLP_ENDPOINT
OTEL_EXPORTER_OTLP_HEADERS if your collector requires auth headers

Set OTEL_SDK_DISABLED=true to turn tracing off without changing code.

Load testing

A basic k6 scenario lives at loadtest/k6/smoke.js. Run it with:

npm run test:load

Override the target with:

BASE_URL=http://localhost:3001/api/v1 npm run test:load

Success response shape

For reference, successful responses use the complementary envelope:

{
  "success": true,
  "data": { ... }
}

Monetary values are returned as strings in 7-decimal fixed-point format matching Stellar asset precision (e.g. "10.0000000").

Security & database configuration notes

Input sanitization: a global middleware (InputSanitizationMiddleware, registered in src/main.ts) trims every string in JSON/urlencoded request bodies and escapes </> before validation and persistence, so markup cannot survive into stored values or reflected responses.
Connection pooling: Prisma pool sizing is applied at runtime to the datasource URL (connection_limit=10, pool_timeout=10, connect_timeout=5). Override each value with DATABASE_CONNECTION_LIMIT, DATABASE_POOL_TIMEOUT, DATABASE_CONNECT_TIMEOUT, or by putting the parameter directly in DATABASE_URL.

Oracle data sources

Data	Source	Key required
Rainfall, temperature, wind	Open-Meteo	No
Flight delay	AviationStack	Yes (`AVIATIONSTACK_API_KEY`)
DeFi exploit	Stellar RPC event stream	No

Project layout

src/
├── main.ts                          bootstrap, Swagger, global middleware
├── app.module.ts                    root module
├── stellar/
│   ├── stellar.module.ts
│   └── stellar.service.ts           keeper keypair, RPC wrapper, tx builder, retry logic
├── oracle/
│   ├── oracle.service.ts            fetch external data, persist to DB
│   ├── oracle.worker.ts             @Cron hourly poll + on-chain submit stub
│   ├── oracle.controller.ts         REST endpoints
│   └── dto/oracle-reading.dto.ts
├── policy/
│   ├── policy.service.ts            premium calculation, DB reads/writes
│   ├── policy.controller.ts         REST endpoints
│   ├── policy.module.ts
│   ├── policy-status.machine.ts     state machine for valid policy transitions
│   └── dto/
│       ├── buy-policy.dto.ts
│       └── policy-response.dto.ts
├── claims/
│   ├── claims.service.ts            claim submission, duplicate guard, auto-process
│   ├── claims.worker.ts             @Cron hourly scan of expiring policies
│   ├── claims.controller.ts         REST endpoints
│   ├── claims.module.ts
│   └── dto/submit-claim.dto.ts
├── auth/
│   ├── auth.middleware.ts           Stellar signature verification
│   ├── auth.controller.ts           POST /auth/login
│   ├── auth.module.ts
│   └── jwt.service.ts               JWT sign/verify
├── health/
│   ├── health.controller.ts         GET /health
│   └── health.module.ts
├── prisma/
│   ├── prisma.service.ts
│   └── prisma.module.ts
└── common/
    ├── filters/
    │   └── http-exception.filter.ts  structured error responses
    ├── interceptors/
    │   └── logging.interceptor.ts    request duration logging
    └── guards/
        └── throttle.guard.ts         IP-based rate limiting

Keeper account

The keeper is a Stellar account (KEEPER_SECRET_KEY) that signs:

oracle-verifier.submit_data(...) — one tx per oracle reading per hour
claims-processor.auto_process(policy_id) — one tx per active policy per hour

Fee per tx: ~0.00001 XLM. Fund via stellar keys fund <address> --network testnet on testnet.

v2 roadmap

Full Soroban SDK transaction builder for all write paths (currently stubbed with // TODO markers)
WebSocket subscription for real-time policy/claim status updates
Redis-backed rate limiting for multi-instance deployments

Name		Name	Last commit message	Last commit date
.github/workflows		.github/workflows
loadtest/k6		loadtest/k6
prisma		prisma
src		src
.dockerignore		.dockerignore
.env.example		.env.example
.gitignore		.gitignore
Dockerfile		Dockerfile
PULL_REQUEST_TEMPLATE.md		PULL_REQUEST_TEMPLATE.md
README.md		README.md
SECURITY_FIXES_313_324_325.md		SECURITY_FIXES_313_324_325.md
docker-compose.yml		docker-compose.yml
entrypoint.sh		entrypoint.sh
package-lock.json		package-lock.json
package.json		package.json
tsconfig.build.json		tsconfig.build.json
tsconfig.json		tsconfig.json

Navigation Menu

Uh oh!

Repository files navigation

parashield-backend

Architecture

Authentication

API key rotation

API Endpoints

Policy

Claims

Oracle

Auth & Health

Local Setup

Production build

CORS configuration

Production CORS example

Error handling

Error codes

Handling validation errors (400)

Rate limiting (429)

Secrets management

OpenTelemetry tracing

Load testing

Success response shape

Security & database configuration notes

Oracle data sources

Project layout

Keeper account

v2 roadmap

Related

About

Releases

Packages

Contributors

Languages

Uh oh!

Latest commit

History

Folders and files

Repository files navigation

parashield-backend

Architecture

Authentication

API key rotation

API Endpoints

Policy

Claims

Oracle

Auth & Health

Local Setup

Production build

CORS configuration

Production CORS example

Error handling

Error codes

Handling validation errors (400)

Rate limiting (429)

Secrets management

OpenTelemetry tracing

Load testing

Success response shape

Security & database configuration notes

Oracle data sources

Project layout

Keeper account

v2 roadmap

Related

About

Resources

Stars

Watchers

Forks

Releases

Packages

Contributors

Languages