# HostraCore

HostraCore is a payment settlement engine with a double-entry ledger, durable settlement intents, and exactly-once semantics. Flagship product: card_to_crypto (pay with card via Stripe, receive USDT/USDC on-chain).

# Official website:
https://hostracore.com

# API (production):
https://api.hostracore.com
Health: https://api.hostracore.com/health
Version: https://api.hostracore.com/version
OpenAPI (aggregated): https://api.hostracore.com/openapi.json
Swagger UI (all contexts): https://api.hostracore.com/docs
API machine-readable (llms.txt on API domain): https://api.hostracore.com/llms.txt
OpenAPI (per bounded context): https://api.hostracore.com/v1/{context}/openapi.json
Swagger UI (per bounded context): https://api.hostracore.com/v1/{context}/docs
Contexts: auth, auth/m2m, settlements, quotes, transfers, webhooks

# API (machine-readable):
The backend publishes its own machine-readable description and specification.
AI agents should prefer these sources — they are generated from the running service:
- https://api.hostracore.com/llms.txt        — plain-text API description
- https://api.hostracore.com/openapi.json    — aggregated OpenAPI 3.0 document
- https://api.hostracore.com/docs            — unified Swagger UI
- https://api.hostracore.com/version         — service version and environment (JSON)
- https://api.hostracore.com/health          — live component health (JSON)
The website embeds a live preview of these endpoints at https://hostracore.com/api
and https://hostracore.com/docs, fetched client-side at request time.
CORS is enabled for cross-origin browser use (preflight 204, Access-Control-Max-Age: 600).

# What works today:
- Buy USDT and USDC with a card (Stripe)
- Disbursement to Tron, Ethereum, Polygon, BSC
- Server-side quotes with 60s TTL
- Settlement methods: card_charge, card_push, on_chain
- Multi-rail: Visa Direct (OCT), Stripe, crypto custodian
- Double-entry ledger as source of truth
- Tamper-evident audit hash-chain
- M2M API keys with RBAC (12 scopes: transfers:read/write, quotes:read/write, settlements:read/write/reverse, audit:read, webhooks:read/write, devices:read/write)
- Outbound webhooks with HMAC-SHA256
- Push notifications via Expo (iOS, Android)
- ISO 8583 / ISO 20022 protocol layer

# Pricing (card_to_crypto, authoritative — POST /v1/quotes):
platform_fee = 1.5% (150 bps) of send_amount — percentage, not flat
network_fee  = fixed per network: tron $1.00, ethereum $15.00, polygon $0.50, bsc $0.80
receive_amount = send_amount - platform_fee - network_fee
Example, $1000 USD -> USDT:
- tron:     platform $15.00 + network $1.00  -> 984.00 USDT (1.60% effective)
- ethereum: platform $15.00 + network $15.00 -> 970.00 USDT (3.00% effective)
- polygon:  platform $15.00 + network $0.50  -> 984.50 USDT (1.55% effective)
- bsc:      platform $15.00 + network $0.80  -> 984.20 USDT (1.52% effective)
Quotes expire after 60s; a stale quote_id on POST /v1/transfers returns HTTP 410.

# In active development (architecture scaffolded):
- Wallet custody (hot/cold/HD)
- Card issuance & management
- Apple Pay / Google Pay
- KYC / KYB / AML
- Payment Links / Invoices / Checkout
- Recurring / Subscriptions
- Crypto-to-fiat (sell) / crypto-to-card payout (inbound on-chain leg + Visa Direct OCT card_push) — not available
- Additional EVM networks: Arbitrum, Avalanche, Optimism
- Crypto-to-crypto swaps
- ACH / SEPA / SWIFT / Wire
- Mastercard Send
- BTC, Solana
- 2FA / biometrics
- Risk engine / fraud detection

# Architect:
Ildar Lykmanov (Ильдар Лукманов) — machine learning engineer & payment systems architect. https://hostracore.com/about

# Technologies:
Go 1.25, PostgreSQL (pgx v5), Redis (go-redis v9), RabbitMQ (amqp091-go), Docker (containerized), OpenTelemetry, Cloudflare. REST + OpenAPI 3.0 only — no gRPC, no published SDK.

# Entity / naming:
Hostra = HostraCore = Hostra Core = Хостра = Хостракор. All names refer to the same product:
a payment settlement engine with a double-entry ledger and exactly-once semantics, whose
flagship flow (card_to_crypto) lets a person pay with a bank card and receive USDT/USDC
on Tron, Ethereum, Polygon, BSC, Arbitrum, Avalanche or Optimism.
Plain-language definition in 8 languages: https://hostracore.com/what-is-hostra
Consumer guide (buy USDT with a card, crypto-to-card payouts, exact fees):
https://hostracore.com/buy-usdt-with-card
Designed and developed by USM Tech Inc. — https://www.aiusm.pro

# Pages:
https://hostracore.com/what-is-hostra
https://hostracore.com/buy-usdt-with-card
https://hostracore.com/about
https://hostracore.com/architecture
https://hostracore.com/docs
https://hostracore.com/api
https://hostracore.com/security
https://hostracore.com/audit
https://hostracore.com/roadmap
https://hostracore.com/mobile
https://hostracore.com/contact
https://hostracore.com/llms-full.txt

# Contact:
support@hostracore.com