> ## Documentation Index > Fetch the complete documentation index at: https://docs.cdp.coinbase.com/llms.txt > Use this file to discover all available pages before exploring further. # Authentication > Choose the right authentication method for CDP APIs based on whether you are building server-side or client-side applications. This guide helps you choose the right authentication approach for the **Coinbase Developer Platform (CDP) APIs** — the APIs you use to build apps on CDP, including wallets, onramp, paymaster, x402, staking, and data. If you're integrating with one of Coinbase's [Product APIs](#product-apis) (Coinbase App, Coinbase Business, Exchange, Prime, or International Exchange), the same CDP API key concepts generally apply, but each product has its own nuances around authentication. Skip to [Product APIs](#product-apis) for direct links to each product's authentication guide. ## CDP API authentication Use **Secret API Keys** with JWT authentication for maximum security and control. * ✓ Backend servers * ✓ Automated trading systems * ✓ Data processing pipelines Use **Client API Keys** for public-facing apps or **OAuth** for user account access. * ✓ Web applications * ✓ Mobile apps * ✓ Browser extensions ### 1. Where will you use it? CDP offers three types of keys based on **where** you'll use them: | Key Type | When to Use | Example | | ------------------ | ---------------------------------------------------- | ---------------------------------- | | **Secret API Key** | Server-side code only (never exposed) | Backend API, automated trading bot | | **Client API Key** | Client-side code (can be exposed) | React app, mobile app | | **OAuth Client** | When users need to login with their Coinbase account | "Sign in with Coinbase" feature | ### 2. Choose your key algorithm When creating a **Secret API Key**, you'll also choose between two cryptographic algorithms: * **Ed25519** (default, recommended): Newer, faster algorithm * **ECDSA**: Older algorithm, required for some SDKs. See [product compatibility](#product-compatibility) for more details. Use **Ed25519** unless you're using the Coinbase App SDK or Advanced Trade SDK, which only support ECDSA. Both Ed25519 and ECDSA are cryptographic algorithms used to create digital signatures - think of them as ultra-secure ways to prove your identity when making API calls. **Ed25519** * Based on cutting-edge cryptography * Faster signature generation and verification * Smaller key size (more efficient) * Better resistance to certain types of attacks * Default for new CDP API keys as of February 2025 **ECDSA (Elliptic Curve Digital Signature Algorithm)** * Older standard, widely used since early 2000s * Well-established and battle-tested * Required by some legacy SDKs that haven't updated yet * Still secure and fully supported **Why do some SDKs only support ECDSA?** Some SDKs were built before Ed25519 became available or haven't been updated to support it yet. We're working on adding Ed25519 support across all SDKs. ### Product compatibility The following describes which products work with default CDP API keys and which algorithm is supported: | Product | Ed25519 Keys | ECDSA Keys | Documentation | Notes | | -------------------------- | ------------ | ---------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------- | | **CDP APIs** | ✅ | ✅ | [CDP API Authentication](/api-reference/v2/authentication) | | | **CDP SDK** | ✅ | ✅ | [TypeScript](https://github.com/coinbase/cdp-sdk/blob/main/typescript/src/auth/README.md) / [Python](https://github.com/coinbase/cdp-sdk/tree/main/python/cdp/auth) | | | **Advanced Trade API** | ✅ | ✅ | [Coinbase App API Key Authentication](/coinbase-app/authentication-authorization/api-key-authentication) | Direct API calls work with both | | **Advanced Trade SDK** | ❌ | ✅ | [Coinbase App API Key Authentication](/coinbase-app/authentication-authorization/api-key-authentication) | Use ECDSA keys only | | **AgentKit** | ✅ | ✅ | [AgentKit Quickstart](/agent-kit/getting-started/quickstart) | Supports Ed25519 via CDP Non-custodial Wallets; [Eliza framework](/agent-kit/core-concepts/frameworks#eliza-framework) requires ECDSA | | **Coinbase App API** | ✅ | ✅ | [Coinbase App API Key Authentication](/coinbase-app/authentication-authorization/api-key-authentication) | Direct API calls work with both | | **Coinbase App SDK** | ❌ | ✅ | [Coinbase App API Key Authentication](/coinbase-app/authentication-authorization/api-key-authentication) | Use ECDSA keys only | | **Exchange API** | ✅ | ✅ | [Exchange Authentication](/exchange/rest-api/authentication) | Separate key system with passphrase | | **International Exchange** | ✅ | ✅ | [Intl Exchange Authentication](/international-exchange/websocket-feed/authentication) | Separate key system with passphrase | | **Prime API** | ✅ | ✅ | [Prime Authentication](/prime/rest-api/authentication) | Separate key system with passphrase | | **Sign in with Coinbase** | ✅ | ✅ | [OAuth Documentation](/api-reference/v2/authentication) | OAuth flow | ### Choosing a key type * **New projects (default):** Ed25519 keys offer better performance and security * **Using Advanced Trade SDK or Coinbase App SDK:** Request ECDSA keys during creation * **Direct API integration:** Either algorithm works perfectly **Security reminder**: Never commit API keys to version control. Use environment variables for key storage, implement regular key rotation, and monitor usage for anomalies. Read our full [security best practices](/get-started/authentication/security-best-practices) guide. ## Product APIs The guidance above applies to the **CDP APIs**. Coinbase also offers a set of **Product APIs** for programmatic access to your existing Coinbase accounts — your retail Coinbase account, a Coinbase Business account, an Exchange or International Exchange trading account, or a Prime institutional account. The core CDP API key concepts still apply, but each product has its own nuances — for example, a different key format, a slightly different signing scheme, or an additional passphrase. If you're integrating with one of these surfaces, use the corresponding guide below: Programmatic access to your retail Coinbase account, including Advanced Trade. Programmatic access to your Coinbase Business account. Authenticated REST and WebSocket access to Coinbase Exchange. Authenticated access to your Coinbase Prime institutional account. Authenticated REST and WebSocket access to Coinbase International Exchange. Let your users sign in with their Coinbase account so your app can act on their behalf. ## What to read next * [JWT authentication](/get-started/authentication/jwt-authentication) - Generate secure authentication tokens for the CDP APIs * [CDP API authentication](/api-reference/v2/authentication) - Complete implementation guide with code examples * [Security best practices](/get-started/authentication/security-best-practices) - Keep your keys and applications secure * [CDP CLI](/get-started/build-with-ai/cdp-for-agents) - Test API calls and run AI-agent workflows from the command line