Why Git Protocol v2 Only?

nanogit speaks only Git Smart HTTP Protocol v2. It does not implement the legacy v1 protocol (neither the original "smart" v1 negotiation nor the "dumb" HTTP protocol), and it will not silently fall back to it. This is a deliberate design decision, not a missing feature:

• Stateless by design — Protocol v2 replaces v1's stateful, multi-round want/have negotiation with a command-oriented request model that completes in a single stateless HTTP round trip. That maps directly onto nanogit's stateless, serverless-friendly architecture. v1's negotiation assumes connection state that nanogit deliberately does not keep.
• Server-side ref filtering — v2's ls-refs command lets the client request only the references it needs (via ref-prefix). v1 dumps the entire ref advertisement on every info/refs request, which is wasteful for repositories with thousands of branches and tags — exactly the multitenant, large-repo case nanogit targets.
• Smaller surface area — Supporting both protocols would double the negotiation and parsing code paths. Minimal surface area is a core design principle: less code means fewer bugs and a smaller attack surface.
• Broad (not universal) provider support — Protocol v2 has been available since Git 2.18 (2018) and the default fetch protocol since Git 2.26 (2020). GitHub, GitLab, and Bitbucket all support it. The notable exception is Azure DevOps / Azure Repos, which only speaks protocol v1 — nanogit cannot talk to it, and there is no fallback. For nanogit's target audience (cloud-native services talking to modern hosted Git), the trade-off is worth it: v1 support would add complexity to serve a shrinking set of servers.

Fail fast, not degrade

When a server only speaks v1, nanogit fails fast rather than silently degrading:

• In code, IsServerCompatible (see protocol/client/compatibility.go) detects the server's protocol version up front and treats a v1-only server as incompatible.
• From the terminal, nanogit check reports the server as incompatible, and every operation fails with a clear error.

Always run the check against a new provider before integrating. See the Server Compatibility guide for how to verify support.

Related

• Architecture Overview — the design principles this decision serves
• Learn how Git works — the upstream protocol documentation, including the v2 specification