The execution and trust layer for AI agents — built on MCP and A2A, backed by a marketplace of verified, reusable functions. Every call audited. Every result provable.
What's under the hood
Precision infrastructure. Zero-trust execution.
Sandboxed Execution
Every function runs in an isolated gVisor container. No shared memory, no escape vectors, no trust assumed.
gVisor · runscExecution Receipts
Cryptographically signed receipts for every call. Immutable, timestamped, verifiable by any party downstream.
SHA-256 · SignedMCP + A2A Native
First-class Model Context Protocol and Agent-to-Agent support. Drop into any AI orchestration layer without rewiring.
MCP · A2ADeveloper Marketplace
Publish, discover, and monetize sandboxed functions. Every listing is a verified, execution-ready artifact.
MarketplaceAuth Proxy + Routing
Centralized auth and intelligent routing across agent calls. The most direct, secure path between your agents and the open internet.
Auth · RoutingRelay Message Bus
Async-first message bus for agent-to-agent coordination. Fire and forget, or await — your architecture, your rules.
Async · RelayLanguage Support
Your language. Your runtime. Our sandbox.
Wasm + WASI per-request sandbox. Every invocation gets its own clean execution environment.
Execution and routing with cryptographic verification. Zero-trust by default.
Who benefits most
Built for every stage. Trusted by all.
Indie SaaS Founder
Deploying your first app
You built an amazing product and now need trustworthy agent tooling without enterprise overhead.
- ✓ Python, Go, Rust, JS, WASM support
- ✓ Wasm + WASI sandbox isolation
- ✓ Trust scores and verification tiers
- ✓ Pay as you grow
Growing Startup
Scaling agent + API workloads
Your team is shipping fast and agents are calling more tools every week.
- ✓ Multi-level verification workflows
- ✓ Agent swarm orchestration
- ✓ Policy engine for safe execution
- ✓ Multi-provider routing
Enterprise
Governance and compliance
Your organization needs auditability, least-privilege access, and consistent trust policies.
- ✓ Firecracker MicroVMs
- ✓ Multi-level attestations
- ✓ Custom SLAs and audit logs
- ✓ Multi-team patterns
How it works
From code to trusted agent tool in 4 steps.
Write
Implement your function in Python, Go, Rust, JavaScript, or TypeScript. Your code runs in isolation — it cannot phone home or access the filesystem unless you grant capabilities explicitly.
Publish
Run ff check to verify your setup, then ff deploy. FunctionFly bundles your code, compiles it for the target runtime, signs the artifact, and runs multi-level verification checks.
Discover
Agents find your function through manifests and trust filters. Your function's trust score, verification tier, execution history, and capability declarations are all surfaced automatically.
Execute
Agents call your function over HTTPS. FunctionFly routes to the right backend, enforces policy limits, runs in a Wasm sandbox, and records every result for trust scoring.
Every call. Signed. Sealed. Provable.
When an AI agent executes a function through FunctionFly, it gets back more than a result. It gets a cryptographic receipt — a tamper-proof artifact that any downstream system can verify.
No more "did that really run?" No more trust gaps between agents. The receipt is the proof.
Protocol Support
Built for the agentic stack.
Model Context Protocol. Native tool registration, schema validation, and sandboxed handler execution.
Agent-to-Agent protocol. Structured inter-agent messaging with receipt-backed delivery guarantees.
Standard HTTP execution endpoints. Works with any agent framework, any language, any runtime.
High-throughput streaming execution for latency-sensitive agentic workloads at scale.
Ready for takeoff
Your agents deserve
better infrastructure.
Deploy your first sandboxed function in under 5 minutes. No credit card. Full receipt coverage from day one.