Verity Backend

Backend API, Horizon integration, and KYC verifier service for Verity — self-sovereign identity on Stellar.

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What is Verity?

Verity is a decentralized identity protocol built on Stellar and Soroban. This backend service handles:

• DID Resolution API — resolves a DID to its verification status
• KYC Verifier Service — receives documents, passes to external KYC provider, issues credentials on-chain, immediately deletes documents
• OAuth Authorization Service — manages the "Verify with Verity" popup flow for third-party apps
• Indexer Service — listens to Horizon events and indexes DID creation, credential issuance, and revocation into PostgreSQL

The backend never stores user documents. It mediates between the frontend, external KYC providers, and the Stellar blockchain.

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                        verity-backend                           │
│                                                                 │
│  ┌──────────────┐  ┌──────────────┐  ┌──────────────────────┐  │
│  │  DID Module   │  │  Auth Module  │  │  KYC Module          │  │
│  │  ─────────── │  │  ──────────  │  │  ──────────────────  │  │
│  │  Create DIDs  │  │  OAuth flow   │  │  Document upload     │  │
│  │  Wallet mgmt  │  │  Sessions     │  │  KYC provider call   │  │
│  │  Resolution   │  │  Token verify │  │  Credential issue    │  │
│  └──────┬───────┘  └──────┬───────┘  └──────────┬───────────┘  │
│         │                  │                     │               │
│  ┌──────┴──────────────────┴─────────────────────┴───────────┐  │
│  │                    Stellar Service                         │  │
│  │  Horizon API calls, Soroban RPC, transaction building     │  │
│  └──────────────────────────┬────────────────────────────────┘  │
│                             │                                   │
│  ┌──────────────────────────┴────────────────────────────────┐  │
│  │               PostgreSQL (TypeORM)                         │  │
│  │  did, wallets, credentials, issuers, nullifiers,          │  │
│  │  authorization_sessions, connected_apps, indexer_events    │  │
│  └───────────────────────────────────────────────────────────┘  │
└─────────────────────────────────────────────────────────────────┘

Modules

Module	Purpose	Key Endpoints
did	DID creation, wallet management, resolution	POST /did, GET /did/:id, POST /did/:id/wallets
credential	Credential issuance, revocation, validation	POST /credentials, POST /credentials/:did/:type/revoke
auth	OAuth-style "Verify with Verity" popup flow	POST /auth/sessions, POST /auth/sessions/:token/approve
kyc	Document submission and KYC provider integration	POST /kyc/submit, GET /kyc/status/:id
stellar	Stellar SDK integration, Horizon API helpers	(service only, no HTTP endpoints)
issuer	Admin registry of approved KYC providers	GET /issuers, POST /issuers
indexer	Horizon event listener, indexing into PostgreSQL	GET /events, POST /indexer/sync

API Endpoints

All endpoints are prefixed with /api/v1.

DID

Method	Path	Description
POST	/did	Create a new DID
GET	/did/:identifier	Resolve a DID to its verification status
GET	/did/:identifier/wallets	List all linked wallets
POST	/did/:identifier/wallets	Link a new wallet
DELETE	/did/:identifier/wallets/:address	Remove a wallet
PATCH	/did/:identifier/verification	Set verification status (admin)

Credential

Method	Path	Description
POST	/credentials	Issue a credential (issuer only)
GET	/credentials/:did	List all credentials for a DID
GET	/credentials/:did/:type	Get a specific credential
POST	/credentials/:did/:type/revoke	Revoke a credential

Auth (OAuth Popup Flow)

Method	Path	Description
POST	/auth/sessions	Create authorization session
GET	/auth/sessions/:token	Get session status
POST	/auth/sessions/:token/approve	User approves
POST	/auth/sessions/:token/deny	User denies
POST	/auth/tokens/verify	Exchange token for verified signal

KYC

Method	Path	Description
POST	/kyc/submit	Submit document for verification
GET	/kyc/status/:submissionId	Check verification status

Issuer (Admin)

Method	Path	Description
GET	/issuers	List all approved issuers
POST	/issuers	Register a new issuer
DELETE	/issuers/:address	Remove an issuer

Indexer

Method	Path	Description
GET	/events	List indexed Stellar events
POST	/indexer/sync	Trigger manual sync

Health

Method	Path	Description
GET	/health	Health check

Getting Started

Prerequisites

• Node.js 22+
• pnpm
• PostgreSQL 16+
• Docker (optional)

Install

git clone https://github.com/verity-stellar/verity-backend.git
cd verity-backend
cp .env.example .env
pnpm install

Run Locally

# With Docker Compose (recommended)
docker compose up -d

# Or manually
pnpm run migration:run
pnpm run start:dev

Run Migrations

pnpm run migration:run

Environment Variables

Variable	Description	Required	Default
NODE_ENV	development, production, or test	No	development
PORT	Server listen port	No	3000
DB_HOST	PostgreSQL host	Yes	localhost
DB_PORT	PostgreSQL port	No	5432
DB_USERNAME	PostgreSQL user	Yes	—
DB_PASSWORD	PostgreSQL password	Yes	—
DB_NAME	PostgreSQL database	Yes	—
STELLAR_NETWORK	standalone, testnet, or mainnet	Yes	testnet
STELLAR_HORIZON_URL	Horizon API base URL	Yes	—
STELLAR_RPC_URL	Soroban RPC endpoint	Yes	—
STELLAR_PASSPHRASE	Network passphrase	Yes	—
KYC_PROVIDER_API_URL	External KYC provider base URL	Yes	—
KYC_PROVIDER_API_KEY	External KYC provider API key	Yes	—
CORS_ORIGIN	Allowed CORS origin(s)	No	*
SESSION_EXPIRY_MINUTES	OAuth session token lifetime	No	5

Testing

pnpm test           # Unit tests
pnpm run test:e2e   # E2E tests
pnpm run test:cov   # Coverage report

Project Structure

verity-backend/
├── src/
│   ├── main.ts                  # Bootstrap, global pipes/filters, Swagger setup
│   ├── app.module.ts            # Root module
│   ├── app.controller.ts        # Health check endpoint
│   ├── common/
│   │   ├── constants/           # Shared constants
│   │   ├── decorators/          # Custom decorators (@Public)
│   │   ├── filters/             # Exception filters
│   │   └── interceptors/        # Response transformation
│   ├── config/                  # Environment validation, configuration
│   ├── database/                # TypeORM config, migrations
│   └── modules/
│       ├── did/                 # DID management (reference implementation)
│       ├── credential/          # Credential lifecycle (stubs)
│       ├── auth/                # OAuth popup flow (stubs)
│       ├── kyc/                 # KYC verification (stubs)
│       ├── stellar/             # Stellar SDK integration (stubs)
│       ├── issuer/              # KYC provider registry (stubs)
│       └── indexer/             # Horizon event indexing (stubs)
├── test/                        # E2E tests
├── Dockerfile                   # Multi-stage Docker build
├── docker-compose.yml           # Local dev with PostgreSQL 16
├── .github/                     # CI, issue templates, PR template
└── package.json                 # pnpm, NestJS 11, TypeORM

Contributing

See CONTRIBUTING.md.

License

MIT License — see LICENSE.