GoKawiilAt Nango, we build open source infrastructure for product integrations.
With all the recent advancements in coding models, we wanted to see how far we can push an autonomous agent building integrations with external APIs.
TL;DR: Our background agent isn’t perfect, but it reliably generates ~200 integrations across five APIs (Google Calendar, Drive, Sheets, HubSpot, and Slack) in 15 minutes and less than $20 in token costs.
Previously, this would have taken an engineer about a week.
This post is about what it took to get there, what broke along the way, and what we learned building a background coding agent for API integrations.
Try it yourself: Our Nango AI builder lets you build custom API integrations with the skills from this article.
Our setup
The pipeline is pretty simple:
We define a list of interactions to build, for example create-calendar-event , sync-files , or send-slack-message Our orchestrator prepares one workspace per interaction with the right Nango integrations scaffolding generated by our CLI We spawn one OpenCode agent per interaction Each agent independently builds its interaction, tests it with the external API (the agent has access to a test account), and iterates until it works Once all agents finish, the orchestrator checks their work and assembles the individual interactions into one Nango integration per API
To make our learnings reusable for customers, we rely heavily on skills. They are easy to publish, work across agents, and adapt to different use cases through a prompt that references them.
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