Simwood
Simwood is a privately held UK-based wholesale telecommunications carrier, founded in 1996, that provides API-first voice, messaging, numbering, and hosted PBX services to carriers, MSPs, and platform operators globally via its proprietary Simwood Potato® core network.
- Company typePrivate
- Founded1996
- HeadquartersSeattle, United States
- Headcount11–50
- GTM typeB2B
- OfferingServices
What Simwood does
Simwood (legal entity Simwood eSMS Limited) is a privately held, founder-led wholesale telecommunications carrier founded in 1996 by Simon Woodhead. Headquartered in Bristol, UK, with regional offices in Spring Hill, Tennessee (US) and Tbilisi, Georgia, the company operates a wholly-owned software-defined core network - the Simwood Potato® - built on Kamailio for over 20 years. The Potato integrates SIP, Microsoft Teams, and PSTN, and exposes the full feature set via a single REST API (v3), enabling carriers, MSPs, platform operators, and dealers to build voice, messaging, numbering, and increasingly AI-driven services without legacy carrier complexity.
The product portfolio spans wholesale carrier services (Platform Connect, Global Connect, wholesale SMS, IP transit), hosted voice services (white-labelled Hosted PBX, SIP trunks, residential VoIP, dealer program), and value-added capabilities (Fraud Protection, BYoC, Microsoft Teams Operator Connect, WhatsApp Business Integration, and Conversational AI Agents). Revenue is generated primarily through usage-based voice termination and SMS plus recurring subscriptions for numbering, hosted PBX, and IP transit, sold through direct API integration, channel partners (carriers, MSPs, VARs), a dealer program offering up to 25% monthly commission, and a self-service portal. Pricing is quote-based, with tiered account structures from Developer through Managed Interconnect.
Simwood is ISO 27001:2013 and ISO 9001:2015 certified, subject to UK Telecommunications Security Act 2021 compliance, and serves challenger carriers and platform operators globally with a stated SLA-backed uptime record (no major outage since 2018). The company has no disclosed institutional funding, no acquisitions, and operates as a cash-generative, independently-run business that recently appointed its first CRO (April 2026) and launched Conversational AI Agents (January 2026) and WhatsApp Calling (December 2025) as the next leg of growth beyond traditional wholesale voice.
Simwood firmographics
Firmographics- Name
- Simwood
- Legal name
- Simwood eSMS Limited
- Website
- https://simwood.com
- Company type
- Private
- Founded year
- 1996
- Operating status
- Operating
- Headcount range
- 11–50 employees
- Short description
- Simwood is a privately held UK-based wholesale telecommunications carrier, founded in 1996, that provides API-first voice, messaging, numbering, and hosted PBX services to carriers, MSPs, and platform operators globally via its proprietary Simwood Potato® core network.
- Ownership category
- akta.pro rank
Where Simwood is headquartered
LocationHeadquarters
- HQ city
- Seattle
- HQ country
- United States
- HQ region
- North America
Offices3 records
Markets served
Simwood business model
Business model- GTM type
- B2B
- Offering type
- Services
- Cost components
- Personnel, Technology or R&D, Infrastructure, Operations
Revenue model
- Voice Termination Services: Wholesale voice termination providing efficient one-hop routing with clean numbering and guaranteed uptime. Operates with domestic UK and US economics and minimal surcharges.
- Hosted PBX Services: Wholly owned, white-labelled hosted voice platform with bundled minutes, free call recording, wall boarding apps, and fraud protection. Offered to dealers and carriers.
- Numbering Services: UK and international number allocation, including geographic, non-geographic, and mobile numbers. Gold numbers with setup fees and standard numbers with no setup fee.
- SMS Services: Wholesale SMS messaging with delivery reports and international reach.
- IP Transit: IP connectivity services for carriers requiring network interconnection.
- Conversational AI Agents: AI-powered voice and messaging services for enterprise customers, monetisable by carriers and MSPs. Beta testing available now with full commercial availability planned for Q1 2026.
- API Platform Services: Developer API providing programmatic access to all network services. The company's own portal is built entirely on their API, demonstrating the platform's capabilities.
Pricing tiers
| Model | Billing | Price |
|---|---|---|
| Usage-based | Pay-as-you-go | Developer accounts for API testing and development |
| Subscription | Monthly | Wholesale Carrier and Hosted PBX services |
Go-to-market motion2 records
Distribution channels6 records
Marketing channels8 records
Simwood product offering
Product offeringCore offering
Simwood is a wholesale telecommunications carrier providing API-first international voice termination, numbering, messaging, and white-labelled hosted voice services to carriers, MSPs, and platform operators. Its proprietary Simwood Potato® core network integrates SIP, Microsoft Teams, and PSTN to enable partners to deploy value-added features such as call recording, fraud protection, and Conversational AI agents through a single API.
Product overview
Simwood is a UK-based software-defined carrier specialising in innovation-driven wholesale telecoms. The company operates a platform-plus-products architecture anchored by the Simwood Potato®, a dynamic core network that integrates SIP, Microsoft Teams, and PSTN to enable carriers and platform providers to deploy value-added services at scale. The product portfolio spans carrier services (Platform Connect, Global Connect, SMS, IP Transit), hosted voice services (Hosted PBX, SIP Trunks, Residential VoIP), and advanced features (WhatsApp Business Integration, Conversational AI Agents, Fraud Protection, BYoC). All services are API-first and programmable, with the Simwood Developer API enabling full account and service management. The company serves carriers, MSPs, VARs, and platform operators globally, with physical footprint in UK and US.
Differentiator
Problem solved
Functional benefit
Products and services
- Simwood Potato® Wholly-owned, dynamic core network platform enabling carriers and platform providers to rapidly deploy value-added features (call recording, sentiment analysis, fraud protection, transcoding) at carrier scale through a single API integration.
- Platform Connect Carrier platform service providing stability, clean numbering, guaranteed uptime, API-first control, and efficient one-hop routing for partners needing PSTN interconnection.
- Global Connect Global wholesale voice termination with efficient one-hop connection, UK and US domestic economics, minimal surcharges, and direct Tier 1.5/2 access for international carriers.
- Hosted PBX Wholly-owned, white-labelled hosted voice platform with bundled minutes, free call recording, wall boarding apps, and integrated fraud protection for dealers and carriers reselling to end enterprises.
- WhatsApp Business Integration Native WhatsApp for Business voice integration enabling carriers, MSPs, and platform operators to connect enterprise customers with global users through encrypted voice and messaging services with AI-driven sentiment analysis.
- Conversational AI Agents AI agents enabling carriers and MSPs to deploy, scale and monetise AI-powered voice and messaging services for enterprise customers, registering as PBX extensions directly on UCaaS platforms for on-net integration.
- BYoC (Bring Your Own Carrier) Network integration service enabling customers to bring their own carrier estate and integrate it with Simwood globally, supporting enterprise mobile call recording, out-of-region numbering, granular call routing, and advanced transcoding.
- Wholesale SMS Wholesale SMS messaging service for carriers and platform operators with delivery reports and international reach.
- IP Transit IP transit services providing network connectivity and interconnection for carriers.
- Hosted SIP Trunks SIP trunking service as part of the hosted voice platform, available through Simwood's dealer network for enterprises.
- Residential VoIP VoIP service for residential customers offered through Simwood's dealer channel.
- Fraud Protection Network-level fraud protection service shielding customers from fraudulent and nuisance calls through advanced filtering algorithms that exceed UK and US legal requirements.
Quantifiable outcome
- 4.8% of traffic filtered beyond legal requirements
- +2 more outcomes
Companies that use Simwood
Customer profileNamed customers5 records
Segments4 records
Ideal customer profiles4 records
Simwood technology and API
TechnologyTechnology focussed Yes
API detail
- Has API
- Yes
- API docs
- API detail
Core technology
AI maturity
App detail
Integration2 records
AI capability6 records
Feature6 records
Simwood partnerships and signals
Strategic signalPartnerships
One partnership is on record.
- ThreecoreLive integration with Three network for wholesale telecoms services. Partnership announced October 2025, expanding Simwood's mobile network operator relationships.
Scale indicators5 records
Recent moves5 records
Expansion highlights6 records
Simwood competitors and assessment
Company assessmentBroad incumbents
- Twilio: Global CPaaS leader offering voice, messaging, and video APIs to enterprises and developers. Directly comparable to Simwood on programmable voice/SMS API distribution but operates at vastly greater scale and with a broader enterprise customer base.
- Vonage (Ericsson): Global cloud communications provider owned by Ericsson, offering UCaaS, CPaaS, and conversational AI. Overlaps with Simwood on API-driven voice services and AI agent capabilities, though at much broader enterprise scale.
Direct peers
- Sinch: Sweden-based CPaaS provider offering messaging, voice, and conversational AI APIs globally. Highly comparable to Simwood on wholesale voice termination, SMS, and emerging AI voice services, with overlapping carrier/MSP customer segments.
- Bandwidth Inc. US-based CPaaS provider offering voice, messaging, and 911 services to enterprises and communications platforms. Direct overlap with Simwood on wholesale carrier services and white-labelled UCaaS enablement; notably the prior employer of Simwood's newly-hired CRO.
- Telnyx: US-based communications platform offering private global IP network, voice, messaging, and IoT connectivity via API. Closely comparable to Simwood's API-first wholesale carrier model with own-network infrastructure and SIP/PSTN termination.
- IntelePeer: US-based communications platform provider offering voice, messaging, and AI-powered automation to enterprises and service providers. Comparable to Simwood on carrier-grade API services and emerging conversational AI agent offerings.
- Peerless Network: US wholesale carrier offering voice termination, SIP trunking, and numbering services. Direct competitor to Simwood in the wholesale carrier segment with overlapping focus on PSTN access and numbering services.
- Alianza: Cloud communications platform provider for service providers, offering wholesale voice, hosted PBX, and UCaaS enablement. Directly comparable to Simwood's white-labelled Hosted PBX and carrier service enablement model.
Emerging players
- NetSapiens: UCaaS platform provider enabling service providers to deliver white-labelled voice services. Comparable to Simwood on hosted PBX platform enablement for dealers and carriers, with similar channel-partner-led GTM.
Others
- Voxbone (now Bandwidth): International virtual number provider acquired by Bandwidth, historically offering DIDs and global PSTN access. Comparable to Simwood's numbering services and international carrier footprint, though now operating under Bandwidth's umbrella.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat6 records
Key risks6 records
Key highlights8 records
Customer concentration
Simwood social profiles
Digital presenceSimwood compliance and trust
Trust signalCompliance2 records
Simwood financial estimates
Financial estimateRevenue estimate
Valuation estimate
Simwood leadership team
Management profileNumber of profiles
Profiles5 records
Simwood subsidiaries and ownership
Company hierarchySubsidiaries1 record
Simwood funding detail
Funding detailFunding overview
Funding rounds
Investors
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
Simwood M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about Simwood
What does Simwood do?
Simwood is a wholesale telecommunications carrier providing API-first international voice termination, numbering, messaging, and white-labelled hosted voice services to carriers, MSPs, and platform operators. Its proprietary Simwood Potato® core network integrates SIP, Microsoft Teams, and PSTN to enable partners to deploy value-added features such as call recording, fraud protection, and Conversational AI agents through a single API.
Is Simwood a public or private company?
Simwood is a private company. It is classified as founder individual operated bootstrapped and is currently operating.
When was Simwood founded?
Simwood was founded in 1996. It employs 11 to 50 people.
Where is Simwood based?
Simwood is headquartered in Seattle, United States, in the North America region.
How does Simwood make money?
Seven revenue lines are on record. Voice Termination Services are the primary driver. The others are hosted PBX Services, numbering Services, SMS Services, IP Transit, conversational AI Agents and API Platform Services.
Who are Simwood's main competitors?
Broad incumbents on record are Twilio and Vonage (Ericsson). Direct peers are Sinch, Bandwidth Inc., Telnyx, IntelePeer, Peerless Network and Alianza. NetSapiens is listed as an emerging player. Voxbone (now Bandwidth) is listed as an others.
Does Simwood have an API?
Yes. Simwood provides a REST API (v3) accessible at https://api.simwood.com/v3/ for managing wholesale telephony account and services. The API supports account management, voice termination, inbound numbering, number porting, fax and SMS messaging, Teams Operator Connect, and event-driven webhooks. Authentication uses standard Basic Authentication. TLS v1.1 or higher is mandatory. JSON output format. Asynchronous report generation with hash-based retrieval. Multiple middleware layers including Beanstalkd queues and REDIS for performance and scale. Available at developer, startup, virtual_interconnect, and managed_interconnect account tiers. Developer documentation is at developer.simwood.com.