The 3 Best ACI.dev Alternatives in 2026

Composio lets an agent act inside apps such as Gmail, Slack, GitHub, Salesforce and Notion on behalf of each end user. It runs the OAuth flows, stores and refreshes tokens, and exposes each app as ready-made tools for any framework or MCP client, plus triggers that push app events back to the agent. It states SOC 2 Type II and ISO 27001. The SDK is MIT-licensed; the platform is hosted. Pricing changed for signups from August 15, 2026: Hobby is free with 100,000 tool calls and 50,000 trigger events a month (usage pauses at the cap), Pro is $29/month including $29 of usage, then $0.0003 per tool call and $0.003 per trigger event, and Enterprise is custom with SSO, BAA and zero data retention included. Existing customers keep their old plan until December 31, 2026.

• Largest catalog: 1,500+ apps with managed OAuth
• Generous free tier (100K tool calls)
• SOC 2 Type II and ISO 27001

Arcade.dev runs the tools an agent calls and handles user sign-in for each one, so the agent acts as the authenticated user rather than a shared service account. Every call is limited to what both the user and the agent are allowed to do, and pre- and post-call hooks let you block actions or redact data without forking the runtime. Arcade says its team wrote the MCP tool authorization specification. Custom tools are built with its open-source Python or JavaScript framework (arcade-mcp, MIT). It states SOC 2 compliance, and Enterprise can run in your VPC or fully air-gapped. Free includes 2,000 authorization events and 2,000 tool calls a month; Team is $25/month plus $0.10 per authorization event and $0.01 per tool call; Enterprise is an annual bundle.

• Per-call authorization scoped to user and agent
• Policy hooks to block or redact without forking
• Self-host in your VPC or air-gapped on Enterprise

Nango handles OAuth, API keys and token refresh for 1,000+ APIs and lets you expose any integration as a tool through its MCP server. Unlike tool-calling-only platforms it also runs incremental data syncs and verified webhooks, so the same integration can feed RAG and trigger agents. Integrations are written as code, which coding agents can generate. The code is on GitHub under the Elastic License 2.0: source-available, free to self-host and embed, but not open source by the OSI definition and not resellable as a hosted service. The free self-hosted build covers auth and the proxy; syncs, tool calls and the MCP server need a paid plan or Enterprise self-hosting. Cloud: Free (10 connections, hard-capped), Pay-as-you-go $50/month including $50 of credit ($0.29 per connection, $0.72 per compute hour, $0.50 per GB), Enterprise custom with BYOC.

• 1,000+ APIs with managed OAuth
• Syncs and webhooks as well as tool calls
• Source on GitHub; free self-host for auth