Tender

Tender is an API-first cryptocurrency payment infrastructure platform that enables merchants and developers to accept digital asset payments across multiple blockchain networks through a single integration. Built around a RESTful JSON API, Tender abstracts the complexity of multi-chain payment acceptance so that web stores, applications, and digital platforms can support crypto transactions without maintaining separate blockchain-specific integrations for each network.

Core Mechanism

Tender operates as a hosted payment gateway with a developer-facing API. Merchants create payment requests—denominated in either cryptocurrency or fiat currency—via the API, and the platform handles transaction monitoring, confirmation, and settlement. The production API endpoint (https://secureapi.tender.cash) uses dual authentication: HMAC-signed requests for sensitive merchant operations, while payment initiation and system data endpoints require only an access ID, simplifying the customer-facing side of integrations.

The platform delivers real-time payment and account event notifications through configurable webhooks, allowing merchants to react immediately to payment confirmations, failures, or other status changes. A sandbox environment mirrors the production API, enabling developers to test integrations end-to-end before going live.

Supported Networks and Assets

Tender's API documentation lists nine supported blockchain networks: Ethereum, Avalanche C-Chain, BNB Smart Chain, Polygon, Bitcoin, TRON, Solana, Aptos, and Movement. Native tokens alongside stablecoins—including USDC and USDT—are accepted across these networks, with the full currency list for each chain accessible through Tender's system endpoints rather than a static hardcoded list.

Solana is among the supported networks, positioning Tender as a practical integration point for Solana-native projects that need to serve customers paying from other chains without building separate gateways for each.

API Structure and Features

Tender organizes its API surface into four functional areas:

Payment APIs handle the core merchant flow: initiating payment requests, validating incoming transactions, and retrieving real-time exchange rates. Merchants can denominate payment requests in crypto or local fiat, with Tender applying current market rates to determine the crypto amount due.

Agent APIs provide hierarchical account management, enabling a primary merchant account to create and administer sub-business accounts ("agents"). This supports payment-facilitator-style business models where a platform operator manages multiple downstream merchants through a single Tender integration rather than requiring each merchant to onboard separately.

System APIs expose network and currency metadata, including the list of supported blockchains, tradable assets per chain, and live rate data. Applications can query these endpoints to surface dynamic, up-to-date payment options to customers at checkout.

Webhook APIs allow merchants to register notification endpoints for event delivery, with delivery logs available for monitoring and debugging.

Additional Financial Operations

Beyond standard payment acceptance, Tender supports a broader set of financial operations. Cryptocurrency conversion lets merchants swap assets between coins and chains. Fiat payout functionality allows merchants to withdraw balances to bank accounts. Bulk disbursement supports payroll and distribution use cases over the Stellar network using USDC and XLM.

A fiat-to-crypto on-ramp is also available: customers pay with local fiat currency and receive cryptocurrency directly to their wallet, lowering the friction for merchants who want to serve both crypto-native and traditional payment audiences. Merchants can additionally create subwallets for end-user account management under their primary account, enabling basic custody-like features within the platform.

Developer Tooling

Tender ships JavaScript and React SDKs, a WooCommerce plugin for e-commerce store integration, and an OpenAPI specification for API reference and code generation. The GitHub organization (github.com/Tender-cash) maintains public repositories including forks of the Jupiter Aggregator platform list for Solana and a backend facilitator for the x402 payment protocol, indicating active engagement with Solana ecosystem tooling and emerging agentic payment standards.

Security

All API communication is made over HTTPS. Merchant operations use HMAC cryptographic signatures to authenticate requests, binding each API call to verified credentials and preventing parameter tampering. The platform returns standard HTTP status codes, including 429 responses for rate-limited requests. No public third-party security audit has been identified at the time of writing.

Ecosystem Position

Tender competes in the crypto payment gateway segment with an offering built around network breadth, agent-level account hierarchy, and an integrated fiat on-ramp layer. For Solana-native projects and developers that need to support customers paying from Ethereum, BNB Chain, Bitcoin, or other networks, Tender provides a unified integration point without fragmenting the payment stack across chain-specific processors.