An API-first engine for real performance
Design, launch, and scale voice in days — not months. Fluents exposes a clean, secure API for programmable calls, mid-call logic, data sync, and analytics. It’s everything you need to ship mission-critical voice without wrestling telephony.
Custom-built voice infrastructure that grows with you
No third-party dependencies or hidden markups. Fluents runs on a purpose-built, multi-region voice stack with sub-200ms audio pipelines, so your API calls translate to live experience instantly. You keep control — we handle the hard parts.
Create, update, and orchestrate calls via REST and webhooks. Inject functions mid-call, map variables securely, and subscribe to events for real-time outcomes. Versioned endpoints, idempotency keys, and robust rate limits keep everything predictable.
SIP + carrier flexibility, BYOK for LLM/STT/TTS, observability hooks, RBAC, and audit logs. Encryption end-to-end. This is voice infrastructure, not a weekend script.
API-first, infrastructure-deep
We believe the best infrastructure fades into the background. That’s why we built for reliability first: multi-region failover, evented architecture, and latency-optimized audio so your experiences feel instantaneous. Whether you’re building a new product, integrating with an internal tool, or just want deeper control over your AI calls — this is the platform that was built to handle it, from research to production.
Programmable calls without the pain
- Call Control → create, answer, bridge, transfer, record, and hangup via API; warm handoffs in a single request.
- Mid-call logic → run serverless functions, fetch from external APIs, or branch flows on live variables (CRM status, inventory, risk scores).
- Events everywhere → webhooks for ringing, answered, dispositioned, transcription, sentiment, and custom checkpoints.
- Data sync → push transcripts, summaries, and outcomes to Salesforce, HubSpot, Pipedrive, or your warehouse in real time.
Security, compliance, reliability
- Encryption in transit and at rest, secret rotation, signed webhooks.
- Privacy tooling → redaction for PII/PHI, selective recording, region pinning, consent prompts.
- Governance → RBAC, API keys per environment, audit trails, request logs, and quotas.
Performance at scale
- 99.9% uptime targets across services; US-based performance and governance options.
- Audio round-trip typically <200ms; answer-machine & voicemail detection with smart retries.
- End-to-end concurrency management so launches don’t buckle under load.
Launch voice in days, not months
Use Programmable Calls to control every aspect of your AI calls via APIs: launch calls, inject prompts, handle real-time events, and dynamically route conversation at scale. With Dashboard Sync, every API action reflects instantly in your admin console, letting non-technical teams manage agents, campaigns, and outcomes without writing code. Tight integrations with your CRM, calendar, or analytics tools using built-in webhooks and connectors — no code sprawl.
Built for developers
- OpenAPI spec, Postman collection, and SDKs (Node, Python) to get productive fast.
- Sandbox environments, feature flags, and deterministic testing with mocked telephony.
- Observability
- → streaming events to your logger (Datadog, New Relic, OpenTelemetry) and exports to your lake/warehouse.
Proof, not promises
From cold-start pilots to enterprise migrations, teams choose the Fluents API to ship faster with fewer moving parts. The outcome is the same: lower complexity, higher reliability, and total control over the voice layer.
“What sets Fluents apart is their standout customer support and constant innovation. They’re always evolving the platform to meet our changing needs.”
Let’s Make Calls Work Better Together
We built Fluents to take the pain out of phones. Easy integrations, fair pricing, and support that feels human — all designed to scale with you. Talk to our team and get live in hours, not months.
Frequently Asked Questions
Answers to the most common questions about building on the Fluents API — from mid-call logic to security and scale.
The Fluents API is designed to be developer-first, but business-ready. Every core capability of the platform — agents, prompts, voices, numbers, calls, actions, and webhooks — is available programmatically. That means you can spin up an agent, attach a number, run a campaign, and subscribe to real-time events with just a few API calls.
Because it’s RESTful with predictable endpoints, you don’t need to re-architect your stack. The API integrates directly into existing CRMs, telephony providers (Twilio, Telnyx, SIP), and automation hubs like Zapier or Make. For technical teams, it’s flexible enough to embed into microservices, BPO infrastructure, or compliance-heavy enterprise systems. For business teams, it keeps outcomes aligned with the systems they already use every day.
The short answer: anything you can imagine around conversational voice automation. Developers use the API to:
- Orchestrate calls → Create, update, and end calls programmatically, with access to recordings, transcripts, and real-time event streams.
- Provision numbers → Buy, link, and manage numbers across providers in seconds.
- Deploy agents at scale → Combine voices, prompts, and actions into production-ready AI agents that can answer or dial thousands of calls simultaneously.
- Automate workflows → Use actions and webhooks to sync outcomes with CRMs, trigger follow-up campaigns, or update external databases.
- Embed into apps or portals → From healthcare scheduling tools to financial dashboards, the API makes it easy to insert voice automation where your users already work.
Whether you’re running a BPO, building a SaaS platform, or just need programmable voice infrastructure, the Fluents API gives you building blocks instead of black boxes.
Fluents was built with high-volume, regulated industries in mind. Instead of bolting security on later, the API is designed to support compliance and reliability from day one:
- Scale → Sub-200ms audio latency, multi-region failover, concurrency controls, and retry logic let you run everything from 100 dials to 100,000 without breaking.
- Security → All API keys are managed per environment, with secure token-based authentication and rotation. Endpoints are protected with TLS, and sensitive actions (like external data writes) can be scoped tightly.
- Compliance → Real-time do-not-call syncing, HIPAA-ready audit trails, and region-specific routing keep you aligned with legal frameworks like GDPR, TCPA, and more.
- Observability → Webhooks for transcripts, errors, recordings, and actions give you full visibility into every call — crucial for regulated sectors like healthcare, finance, and law.
In other words, the API isn’t just flexible — it’s enterprise-grade infrastructure for teams that need programmable voice automation they can trust.