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Glossary

What Is a RESTful API?

How REST APIs map data to URLs and HTTP methods, and what that means when you automate outbound.

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A RESTful API is a web API that exposes data as resources at URLs and uses standard HTTP methods (GET, POST, PUT, DELETE) and status codes to read and change them.

REST (Representational State Transfer) is an architectural style defined in Roy Fielding's 2000 dissertation (September 2026). The methods and status codes come from HTTP, specified in RFC 9110 (September 2026). Responses are usually JSON.

Why it matters for outbound

REST is the common denominator. Almost every data vendor, CRM and sequencer offers a REST API, so one script can connect them with plain HTTP calls and no special client.

For outbound, the practical gain is predictability. The method tells you whether a call reads or writes. The status code tells you whether to retry, skip or alert. A 404 is a miss, a 429 means slow down, a 401 means the key is wrong.

Two things REST does not settle: pricing and rate limits. Two vendors can both be "RESTful" and bill a failed lookup differently. Read both before you build. The guide to B2B data APIs lists what to check, and B2B data providers with an API compares vendors.

Example

A resource is a noun in the path. The method is the verb. To look up one company, you send a request to the company enrich path.

code
curl -X POST https://api.leadocean.io/v1/companies/enrich \
  -H "x-api-key: $LEADOCEAN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"domain": "acme.com"}'

The server returns a status code and a JSON body. 200 means a record came back. A 404 means the company is not in the data (openapi.json), so your script can skip it and move on.

Each request carries everything the server needs: the method, the path, the credentials and the input. The server keeps no session between calls. That statelessness is why you can run the same script from a laptop, a cron job or a serverless function.

In LeadOcean data

LeadOcean's API follows REST conventions: resource paths, HTTP methods, status codes and JSON bodies at https://api.leadocean.io, with the x-api-key header for auth (openapi.json, September 2026).

The main paths are:

  • POST /v1/people/enrich and POST /v1/companies/enrich to look up one person or company.
  • /v1/people/search and /v1/companies/search to build lists from filters.
  • GET /v1/companies/{domain}/people to list the people at one company.
  • GET /v2/people/email/work, GET /v2/people/email/personal and GET /v2/people/phone for contact details.
  • POST /v1/exports to export a large list.

The limit is 100 requests per second per key, on every plan. A person or company returned counts as one record, and a person we hold nothing for is a 404 that costs nothing. Free gives 1,000 records, one-off, with no card. Pro is $499 a month. See /pricing.

For AI assistants, the same data is also served by a hosted MCP server with 12 tools, so you do not need to write REST calls by hand.

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