API Partner · Developer Program

Build custom integrations on the Happierleads API.

REST endpoints + webhooks for visitor identification, contact enrichment, waterfall verification, and LinkedIn real-time checks. Sandbox credentials in under an hour. Free tier for builders.

REST + Webhooks TS + Python SDKs Sandbox environment Free developer tier

Get sandbox keys → Read API docs

# Identify a visitor in one call POST https://api.happierleads.com/v1/identify Authorization: Bearer <api_key> { "ip": "203.0.113.7", "cookie": "hl_abc123", "enrich": "company,person" }

Time from signup to live API call

<60 minutes

Create an account, grab a sandbox key, make your first POST /v1/identify. We built the API so you can prototype without a sales call.

Who this is for

What developers build with our API

🏠

Internal tools

RevOps scripts that enrich CRM records, route leads, or de-dupe lists — without standing up a whole data platform.

🔌

Custom integrations

Connect Happierleads to a niche CRM or homegrown system where no prebuilt integration exists.

📦

Embedded features

Add visitor ID to your own SaaS for your users. (For larger embeds, see the OEM program.)

Endpoints you can call

Full API surface

✓POST /v1/identify — IP + cookie → company + person data

✓POST /v1/enrich/company — domain → firmographics, tech stack, funding

✓POST /v1/enrich/person — name + domain → verified email, LinkedIn, title

✓POST /v1/verify/email — 8-provider waterfall confidence score

✓POST /v1/verify/linkedin — real-time LinkedIn employment check

✓Webhooks on visit, lead created, reply classified, meeting booked

✓Bulk endpoints — CSV upload for enrichment & verification at scale

✓OAuth 2.0 + PAT auth — machine-to-machine and user-scoped

How it works

From zero to production in four steps

Sign up

Create a Happierleads account — free tier unlocks a sandbox key.

Build

Use our Postman collection, TS SDK, or Python SDK. Docs are OpenAPI 3.1.

Test

Sandbox returns deterministic test fixtures so you can write repeatable tests.

Ship

Swap to a production key. Upgrade plan when volume grows.

Pricing

Start free. Pay for usage.

$Developer tier — free · 100 lookups/mo, sandbox access, all endpoints

$Pay-as-you-go · per-call pricing once you exceed the free tier

$Bundled with a Happierleads plan · API calls included in your subscription quota

$Enterprise volume · see the OEM program for committed volume pricing

FAQ

Common developer questions

Do I need to talk to sales?

No. Sign up, click "Developers" in settings, grab a sandbox key. Talk to sales only if you're going above the developer tier or need an MSA.

What are the rate limits?

Developer tier: 10 req/s, 100k req/mo. Paid tiers: higher. Burst allowed via exponential backoff headers.

Are there SDKs?

TypeScript and Python maintained by us. Community SDKs for Ruby, Go, and PHP listed in the docs.

How stable is the API?

v1 has been stable since 2023. Breaking changes ship to v2 with 12 months of v1 overlap. Minor additive changes post on the changelog.

What happens if I exceed the free tier?

Calls don't silently fail — you get 402 responses. Add a payment method and you're back on.

Is there a community / support channel?

Public developer Slack with our engineers. Join from the docs site.

Start building in under an hour

Sandbox key, docs, SDKs, sample apps. Everything you need to prototype today.

Get sandbox keys → Read API docs