Every feature. Same pricing. From your stack.

A clean REST API for single address verification, bulk jobs, catch-all resolution, and domain pattern lookup. Authenticate with an API key. Pay only for confirmed results, same as the dashboard.

Authentication

One header. Every request.

Generate an API key from your dashboard. Keys use the ak_ prefix. Pass it as a Bearer token on every request.

Authorization: Bearer ak_your_key_here

API keys are for programmatic access only. Account management, billing, and key generation require dashboard authentication.

Single verification

One address. One result.

Request

curl -X POST https://api.filtrat.io/v1/verify/email \
  -H "Authorization: Bearer ak_your_key" \
  -H "Content-Type: application/json" \
  -d '{"email": "[email protected]"}'

Response — confirmed deliverable:

Response · 200

{
  "email": "[email protected]",
  "status": "verified",
  "confidence": 98,
  "syntax_valid": true,
  "disposable": false,
  "role_account": false,
  "domain_intelligence": {
    "mx_provider": "Google Workspace",
    "gateway": null,
    "real_provider": "Google Workspace",
    "catch_all": false,
    "spf": "v=spf1 include:_spf.google.com ~all",
    "dmarc": "v=DMARC1; p=reject; rua=mailto:[email protected]"
  },
  "catchall_resolved": null,
  "is_cached": false,
  "credits_used": 0.5,
  "credits_remaining": 9847.5
}

Response — catch-all detected (free):

Response · 200

{
  "email": "[email protected]",
  "status": "catchall",
  "confidence": 62,
  "syntax_valid": true,
  "disposable": false,
  "role_account": false,
  "domain_intelligence": {
    "mx_provider": "Google Workspace",
    "catch_all": true
  },
  "catchall_resolved": null,
  "is_cached": false,
  "credits_used": 0,
  "credits_remaining": 9847.5
}

To resolve a catch-all in the same call, add resolve_catchall: true. Costs 3 credits if confirmed, nothing if unresolvable:

Request · resolve catch-all

curl -X POST https://api.filtrat.io/v1/verify/email \
  -H "Authorization: Bearer ak_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "email": "[email protected]",
    "resolve_catchall": true
  }'

Response · 200

{
  "email": "[email protected]",
  "status": "verified",
  "confidence": 98,
  "domain_intelligence": {
    "catch_all": true
  },
  "catchall_resolved": true,
  "is_cached": false,
  "credits_used": 3.0,
  "credits_remaining": 9844.5
}

Bulk verification

Submit a list. Poll until complete. Retrieve results.

Create the job

Upload a CSV file or submit an array of addresses. The job starts immediately and returns a job_id.

File upload

curl -X POST https://api.filtrat.io/v1/bulk/jobs \
  -H "Authorization: Bearer ak_your_key" \
  -F "[email protected]"

Or with a JSON array:

JSON array

curl -X POST https://api.filtrat.io/v1/bulk/jobs/from-list \
  -H "Authorization: Bearer ak_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "emails": [
      "[email protected]",
      "[email protected]",
      "[email protected]"
    ]
  }'

Response · 202 Accepted

{
  "job_id": "d4f7a2b1-8c3e-4f5a-9b2d-1e3f5a7b9c1d",
  "file_name": "contacts.csv",
  "total": 10000,
  "queued": 10000,
  "status": "pending",
  "credits_estimated": 5000.0,
  "credits_remaining": 9847.5
}

Poll for status

Request

curl https://api.filtrat.io/v1/bulk/jobs/{job_id} \
  -H "Authorization: Bearer ak_your_key"

Response · processing

{
  "job_id": "d4f7a2b1-8c3e-4f5a-9b2d-1e3f5a7b9c1d",
  "file_name": "contacts.csv",
  "total": 10000,
  "processed": 6847,
  "verified": 4203,
  "invalid": 1244,
  "catchall": 987,
  "unknown": 413,
  "skipped": 0,
  "status": "running",
  "auto_resolve_catchall": false
}

Response · completed

{
  "job_id": "d4f7a2b1-8c3e-4f5a-9b2d-1e3f5a7b9c1d",
  "file_name": "contacts.csv",
  "total": 10000,
  "processed": 10000,
  "verified": 6200,
  "invalid": 1800,
  "catchall": 1400,
  "unknown": 600,
  "skipped": 0,
  "status": "completed",
  "auto_resolve_catchall": false
}

Poll status until it returns completed or failed. Recommended interval: 2–5s for small jobs, 10–30s for large ones.

Retrieve results

Filter by result type before fetching:

Request · paginated rows

curl "https://api.filtrat.io/v1/bulk/jobs/{job_id}/rows\
?status=verified&offset=0&limit=100" \
  -H "Authorization: Bearer ak_your_key"

Response · 200

{
  "items": [
    {
      "id": "row_a1b2c3d4",
      "index": 0,
      "email": "[email protected]",
      "domain": "snowplow.io",
      "status": "verified",
      "reason": "Mailbox exists",
      "mx_provider": "Google Workspace",
      "role": false,
      "disposable": false,
      "suggested_email": null
    }
  ],
  "total": 10000,
  "filtered_total": 6200,
  "next_offset": 100
}

Or export as CSV:

CSV export

curl "https://api.filtrat.io/v1/bulk/jobs/{job_id}/export\
?status=verified" \
  -H "Authorization: Bearer ak_your_key" \
  -o deliverable_results.csv

Resolve catch-all addresses

Resolve all catch-alls

curl -X POST \
  https://api.filtrat.io/v1/bulk/jobs/{job_id}/resolve-catchalls \
  -H "Authorization: Bearer ak_your_key"

Or resolve specific emails:

Resolve selection

curl -X POST \
  https://api.filtrat.io/v1/bulk/jobs/{job_id}/resolve-catchalls \
  -H "Authorization: Bearer ak_your_key" \
  -H "Content-Type: application/json" \
  -d '{
    "emails": [
      "[email protected]",
      "[email protected]"
    ]
  }'

Only emails with catch-all status are queued. Non-catch-all emails are skipped:

Response · 202 Accepted

{
  "queued": 2,
  "skipped": 0,
  "message": "Queued 2 catch-all emails for resolution.",
  "credits_estimated": 6.0,
  "credits_remaining": 9841.5
}

Resolution runs asynchronously. Poll the job again to track progress.

More endpoints

Everything else available via API.

Domain pattern lookup

POST /v1/domain-intelligence/lookup

7 credits per domain · Cached domains free. Returns naming conventions with usage percentages.

Domain inspection

POST /v1/domain-intelligence/inspect

Always free. Returns MX provider, catch-all status, SPF, DMARC, gateway detection.

Billing status

GET /v1/billing/status

Returns plan and PAYG credit balances, subscription status, and current period.

API key management

GET /v1/api-keys

POST /v1/api-keys

DELETE /v1/api-keys/{key_id}

List, create, and revoke keys. Session auth only — keys cannot create keys.

Limits & pricing

Rate limits and credit costs.

Rate limits

Single verify30 req/min

Bulk job creation5 req/min

Job polling60 req/min

Pattern lookup10 req/min

Domain inspect20 req/min

CSV export10 req/min

Credit costs

Confirmed deliverable0.5 credits

Confirmed bounce0.5 credits

Catch-all resolution3 credits

Pattern lookup7 credits / domain

Domain inspectfree

Catch-all detectionfree

Uncertain / riskyfree

Cached results (180 days)free

Credits are deducted per result, not per request. Every response that deducts credits returns credits_used and credits_remaining.

Full documentation

Every endpoint, every parameter, every response field.

View API docs

200 free credits. No card.