Number Masking & Call Privacy
Let two parties call and text each other through a proxy number without ever seeing the other's real number - session-based, API-driven and built for marketplaces, ride-hailing, delivery and healthcare.
110+
Countries with proxy inventory
<1s
Session set-up via API
100%
Real numbers hidden from both sides
What is Number Masking & Call Privacy?
Number masking, sometimes called a proxy or anonymised calling service, connects two people through a Dollu number so that neither sees the other's real number. A rider and a driver, a buyer and a seller, a patient and a clinician each dial or text the proxy number; our platform recognises the active session and bridges the call or forwards the message to the correct counterparty. When the transaction ends, the session closes and the proxy number is recycled.
The service is entirely API-driven. Your application creates a session by naming the two participants and choosing a country pool; Dollu returns proxy numbers to show each party and keeps the mapping for the duration you specify. Sessions can be one-to-one, one-to-many, or long-lived for recurring relationships. Webhooks report every call attempt, connection, duration and message so your platform can log activity, trigger follow-ups or detect abuse.
Number masking protects users, protects the platform and protects the transaction. Users' personal numbers stay private, reducing harassment and off-platform contact. Platforms keep the interaction on their rails, gaining visibility into whether a booking was fulfilled, whether a delivery was attempted or whether a support call happened. Optional call recording, transcription and analytics support quality assurance and dispute resolution, subject to consent rules in each jurisdiction.
Dollu runs the masking platform on our own numbering inventory in 110+ countries and our carrier-grade voice and SMS core, so proxy sessions are set up in under a second, calls connect with low post-dial delay, and pools scale to millions of sessions a month. Number pools are sized and recycled with configurable cooling-off periods so no user is ever connected to a stale session.
Why choose Dollu for number masking.
The advantages of buying from a carrier that owns its network, interconnects and operations - rather than a reseller.
Protect user privacy
Neither party sees the other's real number, cutting harassment, unsolicited contact and the data-protection exposure of sharing personal numbers between strangers.
Keep interactions on your platform
With calls and texts flowing through the proxy, you see that a driver called a rider or a buyer contacted a seller, and off-platform leakage is harder.
Resolve disputes with evidence
Session logs, optional recordings and transcripts show what happened and when, giving support teams facts rather than competing accounts.
Local numbers, global reach
Proxy numbers from local ranges in 110+ countries mean users dial a familiar local number and pay local rates, wherever your platform operates.
Built to scale with your traffic
Sessions set up in under a second on a carrier core handling billions of minutes a year; pools grow elastically as your marketplace grows.
Capabilities in detail.
Everything included with Number Masking & Call Privacy - the platform features, options and controls you get from day one.
- 01
Session API
Create, extend, update and close sessions with participant numbers, country pool, TTL and mode; retrieve proxy numbers instantly and query session history programmatically.
- 02
Voice and SMS masking
Both calls and text messages between participants are bridged through the proxy number, with SMS available where the country permits two-way messaging on the range.
- 03
Session models
One-to-one for a single transaction, one-to-many for a driver with several deliveries, and long-lived sessions for recurring relationships such as patient and care team.
- 04
Number pools and recycling
Country- and city-level pools sized to concurrent sessions, automatic recycling after session close, and configurable cooling-off periods before reuse.
- 05
Recording, transcription and analytics
Optional per-session recording with consent announcements, speech-to-text transcripts, and dashboards for connection rates, durations and failed attempts.
- 06
Webhooks and event stream
Real-time events for call attempted, connected, ended, missed, message delivered and session expired, with retry and signature verification.
- 07
Fallbacks and controls
Configurable behaviour when the counterparty is unreachable - voicemail, SMS notification, redirect to support - and rules to block calls outside session windows.
- 08
Compliance tooling
Data-retention settings per country, consent prompts, PII minimisation in logs and audit trails to support GDPR, healthcare and financial-services obligations.
How it works.
From first conversation to live traffic - a tracked, engineer-led onboarding with a named owner at every step.
- Step 01
Provision pools
Choose the countries and cities where your users interact; we size proxy pools to your expected concurrent sessions and reserve inventory.
- Step 02
Integrate the API
Create a session when a transaction starts, display the returned proxy numbers in your app and subscribe to webhooks for call and message events.
- Step 03
Bridge calls and messages
Either party calls or texts the proxy; Dollu identifies the session and connects them to the counterparty with real numbers hidden.
- Step 04
Close and analyse
End the session on completion or TTL; the number returns to the pool after cooling-off and session data flows to your analytics.
Which number type fits.
Local, national, mobile, toll-free and short code numbers solve different problems - and carry different KYC and activation profiles. Availability by country is on the coverage matrix.
| Dimension | Local / geographic | National | Mobile | Toll-free | Short code |
|---|---|---|---|---|---|
| Typical use | Local presence, contact-centre inbound, outbound caller ID | Country-wide brand number without a city tie | Two-way SMS, WhatsApp and verification, mobile-first markets | Sales and service lines the caller should not pay for | High-volume A2P SMS, OTP and marketing opt-in |
| KYC burden | Low to medium; a local address is required in some countries | Low; company registration is usually enough | Medium to high; enhanced KYC and limited stock | Medium; a local entity in some countries | High; operator and regulator approval per code |
| SMS-capable | In selected countries (for example US, Canada, UK) | Rarely | Yes - two-way | In selected countries (US and Canada toll-free SMS) | Yes - the primary purpose |
| Caller pays? | Yes, at local rate | Yes, at national or geographic rate | Yes, at mobile rate | No - the number holder pays for inbound | Not applicable; inbound SMS charged at the sender’s standard rate |
| Activation time | Same day to a few days after KYC approval | Same day to a few days | Days; stock-dependent | Days; regulator registration in some countries | Weeks; carrier approval per country |
Who uses this and why.
Typical deployments across carriers, enterprises, platforms and contact centres.
Ride-hailing and mobility
Riders and drivers coordinate pickups by call or text without exchanging numbers; sessions end automatically when the trip completes.
Food and parcel delivery
Couriers reach customers about access or timing through a proxy that expires on delivery, with one-to-many sessions for multi-drop routes.
Marketplaces and classifieds
Buyers and sellers, guests and hosts, or clients and freelancers talk through the platform, keeping personal numbers private and interactions visible.
Healthcare and telemedicine
Clinicians call patients from a proxy so personal mobiles are never exposed, with recording and retention settings aligned to health-data rules.
Recruitment and dating platforms
Early-stage conversations happen through masked numbers until both parties choose to share contact details directly.
Field service and home visits
Technicians and customers confirm appointments and access through session-bound numbers, with logs available for service-quality review.
Technical & commercial specifications.
Key parameters at a glance. Ask us for the full service description and SLA document.
| Coverage | Proxy inventory in 110+ countries; local ranges in 100+ |
|---|---|
| Channels | Voice bridging; SMS relay where two-way messaging is permitted |
| Session set-up | <1 s via REST API; TTL, mode and pool configurable per session |
| Session models | One-to-one, one-to-many, long-lived |
| Events | Signed webhooks for call, message and session lifecycle |
| Recording | Optional per session; consent prompts; transcription; retention per country |
| Pool controls | Auto-scaling pools; recycling; configurable cooling-off |
| Scale | Millions of sessions per month; carrier-grade voice and SMS core |
| Compliance | GDPR-aligned data handling; PII minimisation; audit trails |
| Support | 24×7 NOC; solutions engineering during integration |
How Numbers & DIDs are priced.
Numbers carry a per-number monthly rental set by country and type - local, national, mobile or toll-free - plus per-minute inbound usage. A few countries add a one-time setup or regulatory fee, passed through at cost.
We publish the model, not a public rate card - actual rates depend on destination, route class, volume and regulatory cost. See how every Dollu service is priced.
- Rental per number by country and number type
- Inbound usage per minute; toll-free usage by calling origin
- Bulk and committed-inventory discounts
- Porting priced per number or per project
- Free SIP delivery to your endpoint; no channel fees
- Billing
- Rental invoiced monthly in advance, usage in arrears; prepaid or postpaid
- Commitment
- None on standard inventory; committed inventory earns discounts
Numbers in 110+ countries.
Local numbers in 100+ countries, with national, mobile, toll-free and short-code ranges where the numbering plan allows. The countries below have a full guide - KYC, number types and activation times.
- Australia5/5
- Brazil4/5
- Canada3/5
- France5/5
- Germany5/5
- Hong Kong4/5
- India4/5
- Mexico3/5
- Netherlands5/5
- Philippines3/5
- Saudi Arabia4/5
- Singapore4/5
- South Africa5/5
- United Arab Emirates4/5
- United Kingdom5/5
- United States3/5
The figure on each chip is the number of types available out of those listed for the country; the remainder are on request.
Number Masking - your questions answered.
The questions customers and carriers ask us most often before they interconnect. If yours is not here, our team answers within one business day.
Still have a question?
Ask our solutions teamRelated services.
Services customers commonly combine with Number Masking & Call Privacy.
Keep every conversation on your platform.
Tell us your countries and expected session volumes and we will return pool sizing, pricing and API credentials for a sandbox within two business days.
