HTTP clients

Canonical guidance

• reuse http.Client instances
• bind requests to context when request-scoped
• configure timeouts and transport behavior intentionally
• close response bodies promptly

Use when

• service-to-service HTTP
• external API integrations
• request-scoped outbound calls

Avoid

• creating a new client for every request
• no timeout strategy
• reading only part of a response and leaking the body

Preferred pattern

req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
if err != nil {
	return err
}
resp, err := client.Do(req)
if err != nil {
	return err
}
defer resp.Body.Close()

Anti-pattern

• default-zero client creation scattered across the codebase with no shared policy

Explanation: This anti-pattern is tempting in small helpers, but ad hoc clients and missing body cleanup quietly waste connections and increase latency.

Why

• outbound HTTP is a major source of latency and resource leaks in Go services