API Sections

BRRR's APIs are organised into four independent products. Each section below shows what it does, the integration flow (where applicable), and a list of its endpoints.

Web3 API

BRRR provides a number of blockchain-related API methods for partners to create better user experiences and rich interfaces: with tokens metadata, balances, price charts, etc.

These endpoints are read-only and do not modify any BRRR or on-chain state. They are intended for client-side display and UX calculations.

Endpoints

Endpoint	Purpose
`POST /v4/web3/tag-info`	Resolve a holytag to its public display info (avatar, name).
`GET /v4/web3/token-info/{network}/{address}`	Token metadata + current price for a single token.
`POST /v4/web3/token-metadata`	Extended market data for a token (ranges, supply, market cap).
`POST /v4/web3/token-chart`	Historical price chart data for a token.
`POST /v4/web3/evm-balances`	All EVM token balances for a wallet across supported networks.
`POST /v4/web3/solana-balances`	All Solana token balances for a wallet.
`GET /v4/web3/solana-priority-fee`	Recommended Solana priority fee for transactions.

OTC API

This API provides a simple crypto to fiat and fiat to crypto settlement for a BRRR partner.

OTC orders settle directly between a registered IBAN and a chosen crypto wallet — unlike the Card API flows, which settle into a Holyheld customer's card balance.

Who can use OTC

OTC access is granted through direct conversations with Holyheld. Approved OTC customers receive:

An API key scoped to the OTC API
Access to the Holyheld OTC web application
One or more registered IBANs on file

No self-serve onboarding is available for OTC — contact Holyheld to discuss your use case.

Sell Crypto → EUR on IBAN

  POST /api/v4/otc/sell-crypto/quote
  { network, token, amount, amountType }
           │
           ▼
  Quote returned (quoteId, rate, fiatAmount, confirmDeadline)
           │
           ▼ (before confirmDeadline)
  POST /api/v4/otc/sell-crypto/execute
  { quoteId, ibanId, reference? }
           │
           ▼
  Order created (orderId, receiveAddress)
  → Customer sends tokenAmount to receiveAddress
  → BRRR sends fiatAmount to the IBAN via SEPA

Buy EUR on IBAN → Crypto

  POST /api/v4/otc/buy-eur/quote
  { network, token, amount, amountType }
           │
           ▼
  Quote returned
           │
           ▼ (before confirmDeadline)
  POST /api/v4/otc/buy-eur/execute
  { quoteId, ibanId, reference? }
           │
           ▼
  Order created (orderId, BRRR collection IBAN returned)
  → Customer sends fiatAmount via SEPA from the registered IBAN
  → BRRR delivers tokenAmount to the customer's wallet

Endpoints

Endpoint	Description
`POST /api/v4/otc/sell-crypto/quote`	Quote for selling crypto into EUR
`POST /api/v4/otc/buy-eur/quote`	Quote for buying crypto with EUR
`POST /api/v4/otc/sell-crypto/execute`	Confirm a sell-crypto quote
`POST /api/v4/otc/buy-eur/execute`	Confirm a buy-EUR quote
`GET /api/v4/otc/order/status/{orderId}`	Poll order status

Quotes are valid until their confirmDeadline (typically 10–15 minutes). Attempting to execute an expired quote returns an error — fetch a fresh quote and retry.

Base URL: https://api.brrr.network · Auth: X-Api-Key header

Multi-tenant Settlement API

This API provides capability to BRRR partners to settle crypto to EUR bank account of BRRR partners and their customers. Risk scanning and processing is integrated into a seamless flow, supporting all networks that are supported by BRRR.

Integration flow overview

The complete integration lifecycle follows this sequence:

┌──────────────────────────────────┐
│           PARTNER SYSTEM         │
└─────────────────┬────────────────┘
                  │
┌─────────────────▼────────────────┐
│ 1. Register customer             │ POST /partner/customer/register
│    + link EVM wallet address     │ POST /partner/customer/add-address
│    + (optional) register IBAN    │ POST /partner/customer/add-iban
└────────────────┬─────────────────┘
                 │
┌────────────────▼─────────────────┐
│ 2. BRRR monitors the address     │ (automatic — no API call needed)
│    for on-chain activity         │
└────────────────┬─────────────────┘
                 │ on-chain activity detected
┌────────────────▼─────────────────┐
│ 3. Retrieve risk assessment      │ RISK_ASSESSMENT webhook → Partner
│    Receive webhook or poll       │ GET /partner/risk/by-customer/{customerId}
│    current risk level            │ GET /partner/risk/by-address/{addressEVM}
└────────────────┬─────────────────┘
                 │ risk is LOW or MEDIUM
┌────────────────▼─────────────────┐
│ 4. Create settlement quote       │ POST /partner/settlement/quote
│    (valid for 15 minutes)        │
└────────────────┬─────────────────┘
                 │
┌────────────────▼─────────────────┐
│ 5. Execute settlement            │ POST /partner/settlement/execute
│    (optional: ibanId, reference) │ → Partner sends tokens on-chain
│    Partner sends token transfer  │
│    to receiveAddress             │
└────────────────┬─────────────────┘
                 │
┌────────────────▼─────────────────┐
│ 6. Poll status / receive webhook │ GET /partner/settlement/status/{quoteId}
│    CREATED → CONFIRMED →         │ SETTLEMENT_STATUS_CHANGE webhook
│    PROCESSING → SENT → FINISHED  │
└──────────────────────────────────┘

Functional areas

Customer onboarding — register customers, link blockchain addresses, attach IBANs
Customer info — retrieve a customer's registered addresses and IBANs
Customer offboarding — remove customers, addresses, or IBANs
Risk assessment — retrieve risk scores for customer addresses
Monitoring — track blockchain activity for registered addresses
Settlement quote — request a settlement quote (valid 15 minutes)
Settlement execution — confirm, execute, and poll settlement status
Rates — retrieve exchange rates for supported tokens and networks

Prerequisites

Customers must complete KYC verification through SumSub with a GREEN status before they can be registered. BRRR will not begin monitoring or risk-assessing addresses until this status is confirmed.

Base URL: https://api.brrr.network · Auth: X-Api-Key header

Card API

This API provides integration with a Holyheld customers, allowing to process crypto to fiat and fiat to crypto payments using customers cards and accounts.

2FA confirmation required

Providing operations on behalf of a Holyheld customer requires 2FA confirmation by the customer from the Holyheld App. Your integration must surface the Holyheld-App prompt to the user and wait for confirmation before polling status.

Deposit flow (crypto → card / SEPA)

┌──────────────────────────────────┐
│           INTEGRATOR             │
└─────────────────┬────────────────┘
                  │
┌─────────────────▼────────────────┐
│ 1. Resolve destination           │
│    (A) Crypto to card:           │ POST /v5/offramp/crypto-to-card/tag-hash
│        fetch one-time tagHash    │
│    (B) Crypto to SEPA:           │ POST /v5/offramp/sepa/estimate-fee
│        estimate fee, then        │ POST /v5/offramp/sepa/create-transfer
│        create transfer → tagHash │
└────────────────┬─────────────────┘
                 │
┌────────────────▼─────────────────┐
│ 2. Estimate amounts              │ POST /v5/offramp/crypto-to-card/evm-*
│    (choose EVM or Solana)        │ POST /v5/offramp/crypto-to-card/solana-*
└────────────────┬─────────────────┘
                 │
┌────────────────▼─────────────────┐
│ 3. Execute                       │
│    (A) Calldata for wallet:      │ POST /v5/offramp/crypto-to-card/transaction-data
│    (B) Gasless on customer's     │ POST /v5/offramp/crypto-to-card/execute-gasless
│        behalf → HHTXID           │
└────────────────┬─────────────────┘
                 │
┌────────────────▼─────────────────┐
│ 4. Poll status                   │ POST /v5/offramp/status
│    (by tagHash, tx hash, or      │ OFFRAMP_STATUS_CHANGE webhook
│    HHTXID)                       │
└──────────────────────────────────┘

Withdraw flow (EUR card balance → crypto)

┌──────────────────────────────────┐
│           INTEGRATOR             │
└─────────────────┬────────────────┘
                  │
┌─────────────────▼────────────────┐
│ 1. List available tokens         │ POST /v5/onramp/tokens
│    for the target network        │
└────────────────┬─────────────────┘
                 │
┌────────────────▼─────────────────┐
│ 2. Estimate amounts              │ POST /v5/onramp/eur-amount
│    (token→EUR or EUR→token)      │ POST /v5/onramp/token-amount
└────────────────┬─────────────────┘
                 │
┌────────────────▼─────────────────┐
│ 3. Simulate gas + feasibility    │ POST /v5/onramp/estimate
└────────────────┬─────────────────┘
                 │
┌────────────────▼─────────────────┐
│ 4. Execute                       │ POST /v5/onramp/execute
│    (customer confirms in app)    │ → returns HHTXID
└────────────────┬─────────────────┘
                 │
┌────────────────▼─────────────────┐
│ 5. Poll status                   │ POST /v5/onramp/status
│    (by HHTXID)                   │ ONRAMP_STATUS_CHANGE webhook
└──────────────────────────────────┘

Sub-sections

Sub-section	Contents
Config & Info	Configuration bundle, address validity, FX rates
Offramp — Crypto to Card	Tag Hash, conversion estimates, Transaction Data, Gasless Execution
Offramp — SEPA Transfers	SEPA fee estimation, transfer creation
Offramp — Status	Unified offramp status polling
Buy Crypto (Onramp)	Token listing, amount estimation, execution, status

API Sections ​

Web3 API ​

Endpoints ​

OTC API ​

Who can use OTC ​

Sell Crypto → EUR on IBAN ​

Buy EUR on IBAN → Crypto ​

Endpoints ​

Multi-tenant Settlement API ​

Integration flow overview ​

Functional areas ​

Prerequisites ​

Card API ​

Deposit flow (crypto → card / SEPA) ​

Withdraw flow (EUR card balance → crypto) ​

Sub-sections ​

API Sections

Web3 API

Endpoints

OTC API

Who can use OTC

Sell Crypto → EUR on IBAN

Buy EUR on IBAN → Crypto

Endpoints

Multi-tenant Settlement API

Integration flow overview

Functional areas

Prerequisites

Card API

Deposit flow (crypto → card / SEPA)

Withdraw flow (EUR card balance → crypto)

Sub-sections