On October 1, HellouOne published two things developers had been asking for: the public API documented as an OpenAPI 3.1 specification, and documentation for the HellouOne SDK in two languages. Neither changes what the API does. Both change how quickly a developer can go from reading about it to calling it, which for an integration project is most of the work.
Why OpenAPI 3.1 matters
OpenAPI is the standard way to describe an HTTP API: every endpoint, its parameters, its request and response shapes, and its authentication, in one machine-readable file. Version 3.1 aligns the schema language with JSON Schema, which makes the specification usable by the current generation of tooling. In practice, an OpenAPI 3.1 document gives a developer three things on day one:
Reference docs that are generated from the spec and therefore match the API, rather than a hand-written page that drifts.
Client code generation. Most languages have a generator that turns the spec into a typed client, so calling HellouOne from a backend becomes a matter of importing a package rather than hand-writing requests.
Contract testing and mocking. Teams can validate their integration against the spec before touching production, and mock the API in their own test suites.
There is a fourth, newer benefit. AI coding agents read OpenAPI specifications well. A developer working with an assistant can point it at the spec and get correct calls, which shortens the first afternoon of an integration considerably.
SDK docs in two languages
The HellouOne SDK wraps the API for developers who would rather call methods than build requests. Its documentation now exists in two languages, which reflects where HellouOne's customers are: development teams in Latin America and the United States, often working in Spanish and English on the same project. A developer in Bogotá and a developer in Miami can read the same guide in the language they think in, and share links to the same pages.
What developers typically build
The integrations that come up most often with HellouOne customers are practical ones. Syncing contacts and labels from a CRM or an internal customer database, so the inbox and the AI agents know who is writing. Pushing conversation outcomes back into a system of record, such as a booked appointment or a qualified lead. Triggering a WhatsApp template from an internal event, like an order shipping or a payment failing. And reporting: pulling conversation and sentiment data into the dashboards a business already uses. With a spec and an SDK, each of these is a well-defined task rather than a research project.
Documentation quality also changes who can do the integration. With a spec and a typed client, a small team without a dedicated integrations engineer can connect HellouOne to its CRM in an afternoon, and an agency that onboards several clients can reuse the same client code across accounts. The two-language SDK docs reduce the chance that a detail is lost in translation between a Spanish-speaking operations team and an English-speaking contractor, which is a common shape for projects in the region.
How to use it in HellouOne
Start with the OpenAPI 3.1 document at one.hellou.ai/docs, load it into your API tool of choice to browse the endpoints, and generate a client for your language if the SDK does not cover it. Read the SDK docs in whichever language your team prefers. Authenticate with your HellouOne API credentials from the admin, make a read-only call first, then wire up the write operations your integration needs. If you also use HellouOne's AI agent connectors, the API is the complement: connectors let the AI agent reach into your systems during a conversation, while the API lets your systems reach into HellouOne. Together they make HellouOne a part of your stack rather than a separate tool next to it.
