Reqwest form feature required

--- name: reqwest-form-feature-required description: | Fix for "no method named form found" or "use of unresolved method form" errors when using reqwest in Rust. Use when: (1) reqwest .form() method not found at compile time, (2) sending URL-encoded form data to APIs like OAuth token endpoints, (3) upgrading from older reqwest versions where form worked without feature flag. The form feature must be explicitly enabled in Cargo.toml for reqwest 0.11+. author: Claude Code version: 1.0.0 date: 2026-01-23 --- # reqwest Form Feature Required ## Problem When using reqwest to send form-encoded data (like OAuth token requests), the .form() method may not be available, causing confusing compiler errors that suggest the method doesn't exist. ## Context / Trigger Conditions Error messages you'll see: `` error[E0599]: no method named form found for struct RequestBuilder in the current scope ` or ` error[E0599]: no variant or associated item named form found help: there is a method or with a similar name ` **Common scenarios:** - Making OAuth2 token refresh/exchange requests - Submitting form data to APIs that expect application/x-www-form-urlencoded - Migrating code from reqwest < 0.11 where form was available by default - Using workspace dependencies where not all features are inherited ## Solution Add the form feature to your reqwest dependency in Cargo.toml: `toml # Single crate reqwest = { version = "0.13", features = ["form"] } # With other common features reqwest = { version = "0.13", features = ["json", "form", "rustls"] } # In workspace Cargo.toml [workspace.dependencies] reqwest = { version = "0.13", default-features = false, features = ["json", "form", "rustls", "http2"] } ` **Note:** In reqwest 0.11+, many methods are behind feature flags: - json - for .json() method - form - for .form() method - multipart - for multipart form uploads - cookies - for cookie jar support - stream - for streaming request/response bodies ## Verification After adding the feature, run cargo check and the error should be resolved: `bash cargo check # Should compile without the "no method named form" error ` ## Example **Before (fails to compile):** `rust let response = client .post("https://oauth2.googleapis.com/token") .form(&[ ("client_id", "xxx"), ("client_secret", "yyy"), ("grant_type", "refresh_token"), ]) .send() .await?; ` **Fix in Cargo.toml:** `toml [dependencies] reqwest = { version = "0.13", features = ["form"] } ` ## Notes - This is a common gotcha when using default-features = false with reqwest - The error message suggests or as an alternative method, which is misleading - When using workspace dependencies, ensure features are properly propagated to member crates - The form method serializes data as application/x-www-form-urlencoded - For file uploads, use multipart feature and .multipart()` method instead ## References - reqwest Crate Documentation - reqwest GitHub - Feature Flags - Rust Forum: Can't find method even though feature is in dependencies