Composio vs Nango: Agent Tools vs API Auth Infrastructure
Two names keep coming up when developers build agent integrations. Composio and Nango both help you connect agents to external services. But they solve different problems at different layers of the stack.
Nango is plumbing. Composio is a finished product. Understanding where each one sits will save you from picking the wrong tool for the job.
Nango: auth infrastructure for APIs
Nango is a developer infrastructure product for API authentication. It handles OAuth flows, token refresh, credential storage, and proxy requests to third-party APIs.
Here is what Nango does well. You configure a connection to, say, the Google Calendar API. Nango walks your user through the OAuth consent screen, stores the tokens, refreshes them when they expire, and gives you a proxy endpoint that attaches the right credentials to every request. You never touch a refresh token.
Nango supports 250+ API integrations. But “integration” here means auth support, not pre-built functionality. Nango will get you a valid access token for Salesforce. It will not give you a “search Salesforce contacts” tool that your agent can call.
You build the tools yourself. Nango gives you the authenticated connection. You write the API calls, parse the responses, handle errors, and format the output for your agent.
This is a feature, not a limitation. If you want full control over how your agent interacts with an API, Nango gives you a clean auth layer without opinions about what you build on top of it.
Nango is open source with a hosted option. The self-hosted version is free. The cloud version charges based on connections.
Composio: pre-built agent tools
Composio takes a different approach. It provides 500+ pre-built integrations as ready-to-use agent tools.
Where Nango stops at auth, Composio goes further. A Composio integration with Google Calendar is not just an OAuth flow. It is a set of callable actions: create event, list events, update event, delete event. Each action has a defined input schema and output schema. Your agent calls the action, passes the parameters, and gets structured results.
Composio handles auth under the hood. When an action needs an OAuth token, Composio manages that. But the auth is not the product. The tools are the product.
The platform supports multiple agent frameworks. Composio provides SDKs for LangChain, CrewAI, OpenAI, and others. You import the toolkit, connect it to your agent, and the pre-built actions appear as tools your agent can call.
For teams that want to move fast, this removes a large chunk of integration work. You do not write API calls. You do not parse responses. You do not build error handling for each external service. Composio has already done that.
The tradeoff is flexibility. Pre-built tools make assumptions about what actions matter and how responses should look. If the Google Calendar integration does not expose the exact API field you need, you are limited to what Composio provides.
The distinction
Nango gives you auth primitives. You build the tools. Composio gives you tools pre-built. You configure and connect them.
Think of it this way. Nango is like getting a set of authenticated API clients. You still write the business logic. Composio is like getting a finished integration layer. You wire it into your agent and go.
This is not a quality judgment. It is a scope difference.
If you are building a product where you need precise control over how your agent calls external APIs, Nango makes sense. You own every request, every response transformation, every error path.
If you want to give your agent 50 integrations by next week and you do not need custom API behavior, Composio gets you there faster.
There is a third option worth mentioning. AgentPatch handles auth behind the scenes so you never think about it. You get pre-built tools (like Composio) but accessed through MCP, REST, or CLI with per-call micropayments. No OAuth flows for your users to complete, no token storage to manage. The tools just work when your agent calls them.
How to choose
Pick Nango if you are building a product that connects to user accounts and you need full control over the API interactions. Nango is infrastructure. It fits when you want to own the tool layer and just need someone to handle the auth mess.
Pick Composio if you want pre-built agent tools and you are working within a supported agent framework. Composio fits when speed matters more than customization, and when the pre-built actions cover your use cases.
Pick AgentPatch if you want hosted tools without managing auth for either yourself or your users. AgentPatch fits when your agent needs common capabilities (search, email, maps, image generation) and you want one API key instead of a dozen.
There is overlap between all three. You could use Nango for custom integrations with user-owned accounts, Composio for pre-built actions in an enterprise workflow, and AgentPatch for commodity tools that do not need user-specific auth. They can coexist.
Wrapping up
Composio and Nango occupy different layers. Nango is auth infrastructure. Composio is an agent tool platform. Picking between them depends on whether you want to build your own tools on top of authenticated connections or use tools someone else has already built.
Most teams do not need to choose just one. The agent tooling ecosystem is modular enough that you can mix and match based on what each integration requires.