SendGrid API Key Regex for Go

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching sendgrid api key, ported and verified for Go. In security-sensitive code, using an unverified regex can open the door to both false positives and denial-of-service attacks. The snippet below is ready to drop into your Go project — whether you're validating in a Gin handler, a gRPC service, or a command-line tool.

Go Implementation

// SendGrid API Key
// ReDoS-checked | RegexVault — Security > API Keys & Tokens

package validation

import "regexp"

var sendgridApiKeyRe = regexp.MustCompile(`^SG\.[A-Za-z0-9_\-.]{30,100}$`)

func ValidateSendgridApiKey(s string) bool {
    return sendgridApiKeyRe.MatchString(s)
}

// Example
// fmt.Println(ValidateSendgridApiKey("SG.aBcDeFgHiJkLmNoPqRsTuVw.aBcDeFgHiJkLmNoPqRsTuVwXyZ0123456789aBcDeFg")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Security > API Keys & Tokens category and has been checked for ReDoS risk. That matters for Go developers because Go's RE2 engine is inherently safe from catastrophic backtracking, but this pattern has been additionally verified for correctness. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

SendGrid API keys: SG. + 22-char API key ID + . + 43-char token. Three-part structure, always 69 characters after the SG. prefix. Can be scoped to specific mail operations (send, read stats, manage contacts).