Fystack

Fystack is an enterprise-grade wallet-as-a-service (WaaS) platform that gives fintechs, payment processors, and digital-asset companies a complete custody stack without requiring them to build in-house web3 engineering teams. The platform bundles wallet APIs, a policy engine, treasury automation, compliance tooling, and MPC security into a single deployable solution that runs on Solana, Ethereum, Bitcoin, Tron, BNB Smart Chain, Base, and more than ten other networks.

Core Mechanism: MPCIUM Distributed Cluster

Fystack's security model is built around its open-source MPC (Multi-Party Computation) engine, called MPCIUM. Rather than storing a complete private key anywhere — on a server, in a database, or in an HSM — MPCIUM distributes cryptographic key shares across independent nodes in a cluster. Signing operations are computed jointly across those nodes so that a private key in its entirety never materializes in any single location or process. This eliminates the single point of failure that plagues traditional custodial wallets while preserving the ability for enterprises to apply granular policy controls to every outgoing transaction.

MPCIUM is published as an open-source repository on GitHub under a permissive license and has accumulated over 180 stars from the developer community. The repository is written in Go, reflecting a design emphasis on performance and concurrency suited to high-throughput payment operations. Fystack also open-sources a multichain transaction indexer (used to detect inbound deposits across chains), a TypeScript platform SDK for Node and browser environments, and a programmable policy engine described as "AWS-style Policy-as-code for Web3 wallets and treasuries."

Products and Use Cases

Fystack organizes its commercial offering around three primary use cases:

Stablecoin Payment Rails — Businesses can accept and send USDT and USDC at scale across multiple networks from a single API surface. Automated reconciliation, deposit detection via the multichain indexer, and configurable sweep thresholds mean that operations teams can manage high transaction volumes without manual intervention.

Treasury Management — Enterprises use Fystack's auto-sweep functionality and policy engine to automate fund collection from customer-facing wallets into treasury accounts. Configurable rules trigger consolidation transfers on a schedule or at defined balance thresholds, and role-based approval workflows gate large outgoing transfers behind multi-person authorization.

OTC Desk Solutions — Institutional trading desks can use Fystack as custody and settlement infrastructure, connecting wallet management to their existing OTC workflows through the REST API and SDK.

Key Features

Gas sponsorship is a notable developer-facing feature: end users of applications built on Fystack do not need to hold the native token of whichever chain they are transacting on, because Fystack abstracts gas payment behind the scenes. This is particularly relevant on Solana, where USDC flows are common but new users may not hold SOL for transaction fees.

Real-time monitoring integrates directly with Telegram and Slack, delivering webhook-driven alerts for deposits, withdrawals, policy triggers, and anomalies. The audit trail and role-based access control features are designed to satisfy the compliance requirements of regulated financial entities operating in jurisdictions that require segregation of duties and documented approval chains.

Deployment is available in two modes. The cloud (SaaS) option is a fully managed path, with tiered pricing from a free plan through a $499/month Growth plan, with volume-based outbound limits at each tier. The self-hosted path lets enterprises deploy the complete custody stack on their own infrastructure — AWS, Google Cloud, Azure, Hetzner, Alibaba Cloud, or on-premises hardware — using the published Docker and Kubernetes configurations. Enterprise custom pricing is available for organizations that require dedicated support or custom SLA terms.

Security and Audit

Fystack completed a full security audit with Adevar Labs, with the audit report made publicly available on the Fystack website. The scope of that review covered the MPC wallet infrastructure, the API layer, and deployment configurations. The company also publishes a developer security handbook as a standalone open-source resource covering threat modeling and security best practices for crypto infrastructure, which signals a stated commitment to security transparency beyond just the product itself.

The platform implements encryption at rest, in-memory runtime encryption, data tampering detection, KMS integration, and supply chain and container security hardening as documented in the technical documentation.

Solana Ecosystem Fit

Solana appears in Fystack's supported chain list alongside Bitcoin, Ethereum, Tron, BNB Smart Chain, and Base. For Solana specifically, the platform enables enterprises to receive and send USDC — Solana's highest-volume stablecoin — through the same unified API they use for other networks. The gas sponsorship feature is relevant in the Solana context because it allows businesses to onboard users who hold USDC but may not have SOL for transaction fees, a friction point that enterprise payment integrators routinely encounter.

Superteam, a Solana ecosystem grants and talent network, is listed among Fystack's production customers. This indicates that the platform's Solana integration has been used in a live production context within the Solana community specifically, not just as a supported chain in theory.

Team and History

Specific founding team member names are not documented in publicly available materials. The company lists a founding date of mid-2025 and positions itself as developer-first, with the open-source releases on GitHub serving as the primary public record of its engineering output. The 20+ production instances cited on the website — including Apescreener, Gaian, EXDT, Minepath, and PrimePay in addition to Superteam — suggest the platform reached early commercial traction relatively quickly after launch.

Fystack's open-source posture, with its MPCIUM engine, policy engine, multichain indexer, and security handbook all publicly available, differentiates it from closed custodial platforms like Fireblocks or Cobo, against which the company explicitly positions itself in its blog content. The self-hosted deployment option further distinguishes Fystack for enterprises with data sovereignty requirements that preclude using shared cloud custody infrastructure.