REST API Overview

Score CRM has a real-time API for creating and updating contacts from your own backend, landing pages, or CRM — the moment something happens, instead of waiting for a CSV export.

https://api.scorehq.co

This is a separate host from your dashboard (app.scorehq.co or wherever you log in). It's built specifically for server-to-server traffic — every request is authenticated with an API key, never a user session, and it's designed to be called from your backend, not from a browser.

What it's for

The API exposes two endpoints for the same create-or-update operation, differing only in how many contacts one request carries:

Endpoint	Use for
POST /api/v2/contacts	One contact per call — the common case for real-time sync. Returns a real HTTP status (201/200/409/etc.) for that one outcome.
POST /api/v2/contacts/batch	Up to 50 contacts per call. Always returns 200, with a per-contact result inside results[], since a batch's outcomes can't collapse into one status code.

Use either one whenever something happens in your own systems that should be reflected in Score right away — a signup, a plan change, a form submission — without you having to batch it into a CSV later.

Use this API for...	Use CSV import for...
Real-time sync as events happen (signups, form fills, status changes)	One-time or periodic bulk imports of existing contact lists
Small, frequent updates (one contact, or a handful at a time)	Large historical imports (thousands of rows at once)
Keeping Score in sync with a system of record you already have	Migrating from another platform

Start here

If you're integrating for the first time, read Authentication next to get your API key, then Create or Update a Contact (one at a time) or Sync a Contact Batch (up to 50) for the actual request/response shapes.

What you can do today

• Create a new contact and add them to one or more lists.
• Update an existing contact's fields — but only if you explicitly say so (see overwrite in the Create or Update a Contact guide). Nothing is ever overwritten by accident.
• Add an existing contact to additional lists, which can enroll them in any journey that's watching for new members on that list.
• Send up to 50 contacts in a single request to the batch endpoint, with a per-contact result for each one.

What it doesn't do (by design)

• It can't re-subscribe someone. If a contact has bounced, complained, or unsubscribed, this API can still update their name, phone, or custom fields — but it will never restore their ability to receive email. That protection can't be bypassed from either endpoint.
• It never removes a contact from a list. This API only adds — removing list membership isn't something it does.
• It's not built for bulk historical imports. Batches are capped at 50 contacts per request. For a one-time import of your existing contact base, use CSV import instead.

What's next

• Authentication — how to get and use your API key
• Rate Limits & Retries — how many requests you can make, and how to handle being throttled
• Create or Update a Contact — single-contact endpoint, full request/response reference
• Sync a Contact Batch — batch endpoint, full request/response reference
• Error Codes — every error you might see, and what to do about it