compare · Go
fastC vs Go
Go is a 2010s memory-safe language with a GC, goroutines, and one of the best standard libraries in any language. fastC and Go disagree on memory management, async, capability typing, and binary size.
Go is a 2010s-vintage memory-safe language with a GC, goroutines, and one of the best standard libraries in any language. fastC and Go disagree on memory management (GC vs no-GC), on async (Go has CSP first-class, fastC defers), on capability typing (Go has none), and on binary size (Go's hello world is 40× larger). The choice between them is mostly a choice between Go's ergonomic productivity wedge and fastC's structural-safety wedge.
Row by row
| Dimension | fastC | Go | Note |
|---|---|---|---|
| Memory safety without GC | Yes — runtime traps + contracts | Yes — GC handles memory | Go's GC is the trade; fastC keeps the C runtime model. |
| Capability-typed I/O | Yes — caps flow through signatures | No — any goroutine can call os.Open / net.Dial | fastC's structural wedge over Go. |
| Mandatory contracts on public APIs | Yes — @requires / @ensures, three-tier discharge | No — `panic` is the closest thing | Go's design intentionally avoids contract syntax. |
| No executable build scripts | Yes — declarative manifest only | Yes — `go generate` exists but is not required | Roughly tied; Go's default story is clean. |
| Stripped 'hello' binary | 53 KB | 2.4 MB | fastC ~45× smaller — Go ships GC + runtime in every binary. |
| Compile speed | Fast — ~30% faster than Rust release | Very fast — Go's compile speed is its design wedge | Go wins; the compiler was built around incremental builds. |
| Cross-compile setup | 8 presets via `zig cc` | GOOS / GOARCH, ~40 target combinations natively | Go wins on breadth; fastC's list is smaller but works out of the box. |
| Goroutines + channels | No — async deferred to stage 2.3 | Yes — CSP first-class | Go wins for I/O-heavy server code today. |
| Ecosystem size | 11 curated fastc-core packages | Broad stdlib + the Go module ecosystem | Go wins on breadth; fastC's list is curated. |
| Supply chain | sha256 + cosign + SLSA L3 | Yes — go.sum + module proxy + checksum DB | Roughly tied — Go's supply-chain story is among the best. |
| Audit-by-disassembly | Yes — 53 KB stripped binary | No — 2 MB+ GC + runtime is opaque | fastC wins on the disassemble-and-read story. |
| Readability for new contributors | C-shaped — anyone with C/Rust/Zig taste can read it | A different shape entirely — gofmt + interface{} idioms | Trade-off, not strict win for either. |
Where fastC wins
fastC wins where binary size, capability auditing, and structural safety against agent-written code matter. It wins on the audit-by-disassembly story (53 KB vs 2.4 MB) and on the cap-typed I/O wedge. For systems-language work where every binary needs to be inspectable, fastC is the better fit.
Where Go wins
Go wins on ergonomics, ecosystem maturity, async, and compile speed. Go is the right answer when your team already speaks Go, when you need goroutines for I/O-heavy server work, or when 2.4 MB binaries are fine for the deployment target. Go's stdlib is one of the best in any language; fastc-core is 11 packages.
The honest framing
Go's goroutines are a real productivity win for I/O-heavy server code. fastC's async story is deferred to stage 2.3 and is unlikely to ship the same shape — capability-typed `async = caps(net | time)` is a different model than CSP. The honest read: if your service is goroutine-shaped, Go wins ergonomically until fastC has its own async answer.