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1stContact.ai API Documentation

1stContact.ai provides a comprehensive API platform that enables developers to build integrations, automations, and custom applications with the 1stContact.ai CRM and Marketplace. Our API includes REST endpoints for contacts, messaging, workflows, calendars, payments, webhooks, and more.

IMPORTANT: V1 APIs have reached end-of-support as of 31 December 2025.

Existing connections/integrations will continue to work; however, no support or updates will be provided for V1 APIs. To migrate from V1 to V2 (with a ton of new functionalities and security features), check out Private Integrations.

Older API documentation versions remain accessible for reference, allowing developers to continue supporting existing integrations while reviewing newer API versions when ready to upgrade.

1stContact.ai API Documentation

1stContact.ai API documentation is now available in your account under Developer → API Docs. If you previously used legacy documentation, please update your bookmarks.

1stContact.ai API documentation now supports versioned API references. Developers can use the version switcher inside the API documentation to view endpoints, schemas, parameters, and examples for a specific API version. This helps teams maintain stable integrations, reference older API versions when needed, and plan upgrades to newer versions with more confidence.

1stContact.ai is also working toward the next API milestone, v3, which is expected to introduce enhanced capabilities, improved performance, and new endpoints for advanced use cases. Continue checking the official API documentation for the latest available versions.

How to Use Versioned API Documentation

Versioned API documentation helps developers build and maintain integrations against a specific API version. This reduces the risk of referencing the wrong endpoint structure, request schema, or response format when maintaining production systems or planning migrations.

  1. Open the official 1stContact.ai API documentation.
  2. Use the version switcher in the documentation to select the API version you want to reference.
  3. Review the endpoints, request parameters, schemas, and response details for that selected version.
  4. Use older API versions when maintaining existing integrations.
  5. Review newer versions when planning upgrades or building new integrations.

Versioned documentation does not impact existing integrations. It is designed to make API references clearer and more stable for developers.

Agency Sub-Account

Agency Sub-Account support allows eligible agencies to identify and manage the primary sub-account used for onboarding and configuration.

  • Eligibility or plan scope
  • Read/update endpoint behavior
  • Audit implications if returned in API responses
  • Any uniqueness rules, such as whether only one Agency Sub-Account can exist per agency

How to Get Help or Support for the 1stContact.ai API

IMPORTANT: At this time, 1stContact.ai Support does NOT provide setup code auditing or developer consultative services on API-related topics. However, if your setup is complete and correct — yet an error persists — you may have encountered an API bug we need to fix.

Report a bug via our support form

For any questions relating to the 1stContact.ai API, reach out to our developer community and support team through the Contact page.

The 1stContact.ai team also hosts periodic Developer Council calls — find upcoming sessions on the events calendar.

Agent Studio also supports public APIs for managing agents programmatically. For Agent Studio-specific endpoints and usage guidance, refer to the dedicated Agent Studio API article.

How to Submit a New API-Related Idea to 1stContact.ai

Our API Docs list all available endpoints that are publicly available. If you don't see an endpoint, we recommend submitting your request through our support form.

Differences Between API Access Across Plan Levels

Basic API access is included with our Starter and Unlimited plans, while Advanced API access is available on our Agency Pro plan.

In addition to the future endpoints that will be released in our OAuth 2.0 API (which is only available in our Advanced API access), this tier unlocks the use of Agency API Keys, where lower plan levels only access Location API Keys.

Basic API Access
  • Included on Starter & Unlimited plans
  • Location API Keys
  • Core REST endpoints
Advanced API Access
  • Available on Agency Pro plan
  • Agency API Keys
  • OAuth 2.0 endpoints

What are the Rate Limits for API 2.0?

1stContact.ai has implemented rate limits on our public V2 APIs using OAuth to ensure optimal performance and stability. These limits have been adjusted to:

100
API requests per 10 seconds (burst limit) per Marketplace app per resource
200,000
API requests per day (daily limit) per Marketplace app per resource

These limits contribute to better overall performance and stability of our system.

To monitor your limited usage, refer to the following API response headers:

X-RateLimit-Limit-Daily — Your daily limit
X-RateLimit-Daily-Remaining — Remaining requests for the day
X-RateLimit-Interval-Milliseconds — Time interval for burst requests
X-RateLimit-Max — Max request limit in the interval
X-RateLimit-Remaining — Remaining requests in current interval

Frequently Asked Questions

Q.What is the 1stContact.ai API used for?

The 1stContact.ai API allows developers to build custom integrations, automate workflows, and connect external applications with the 1stContact.ai platform. It provides REST endpoints for contacts, conversations, calendars, workflows, payments, and more.

Q.Does 1stContact.ai still support API V1?

No. 1stContact.ai API V1 has reached end-of-support. While existing integrations may continue to function, no updates or technical support are provided. Developers should migrate to API V2 for ongoing support and new features.

Q.What authentication methods does the 1stContact.ai API support?

1stContact.ai supports:
  • Private Integration Tokens for internal or single-location integrations
  • OAuth 2.0 for public integrations and Marketplace apps requiring user authorization

Q.When should I use OAuth 2.0 instead of a Private Integration Token?

Use OAuth 2.0 when building a public or Marketplace app, accessing multiple locations or accounts, or requiring secure, user-approved access. Private Integration Tokens are best for internal tools or single-account use cases.

Q.What are the API rate limits in 1stContact.ai?

1stContact.ai enforces 100 requests per 10 seconds (per resource) and 200,000 requests per day (per resource). Rate limit headers are returned with each API response for monitoring.

Q.Are there SDKs available for the 1stContact.ai API?

SDKs and code samples are available within the developer documentation under your account. Check the Developer section for the latest available libraries.

Q.How do I get an API key or access token?

Generate a Private Integration Token from your sub-account settings, or register a Marketplace app to obtain OAuth 2.0 credentials. Note: the ability to generate new API keys from Agency and Sub-account settings is being phased out for accounts not currently using one.

Help & Support

Need help integrating with the 1stContact.ai API? Our team is ready to assist with questions, bug reports, and developer resources.

Contact Support