Agentic Index
Retell AI vs Synthflow (2026)
Retell AI and Synthflow serve different builders at similar price points: Retell is the developer platform, pay as you go with no platform fee, voice engine at seven to eight cents a minute plus your LLM and telephony, all in commonly thirteen to thirty one cents, while Synthflow is the no code studio with monthly tiers commonly from around 29 dollars bundling minutes, enterprise from about thirty thousand dollars a year, and a bring your own keys model whose provider fees often double or triple effective cost. If engineers own the agent, Retell's transparent unit economics win; if operators own it, Synthflow's visual builder is the point.
| At a glance | Retell AI | Synthflow |
|---|---|---|
| Category | Customer support agent | Voice agent |
| Entry price | Pay as you go from $0 ($10 free credits); voice engine $0.07 to $0.08/min plus LLM and telephony billed separately; Enterprise custom | Free to build; Starter $29/mo; Ent from $30k/yr |
| Free / trial | $10 in free credits and 20 concurrent calls to build and test, no card | — |
| Pricing confidence | public partial | public exact |
| Feature | ||
|---|---|---|
| Action & orchestration | ||
|
Integrations & Tool Calling Ability to connect agents to real systems through native integrations, OAuth-authenticated actions, custom tools, APIs, webhooks, or MCP-compatible tools. |
Full / Explicit | Full / Explicit |
|
Workflow Orchestration Ability to sequence, branch, retry, route, and combine deterministic workflow nodes with autonomous agent steps. |
Full / Explicit | Full / Explicit |
|
Triggers & Channel Coverage How agents wake up and where they work: schedules, webhooks, message events, CRM events, inbox events, chat, email, voice, and collaboration tools. |
Full / Explicit | Partial |
| Knowledge & context | ||
|
Knowledge Grounding & RAG Ability to ground agent behavior in company data through document ingestion, retrieval, external knowledge APIs, semantic search, or RAG layers. |
Partial | Partial |
|
Memory & State Persistence Ability to persist context across a run, conversation, workflow, user, team, or longer-term memory layer. |
Partial | Partial |
| Control & trust | ||
|
Human Oversight & Guardrails Approval steps, consent checkpoints, escalation rules, structured guardrails, policy constraints, and pause/resume controls. |
Partial | Partial |
|
Security, Identity & Governance RBAC, SSO, auditability, encryption, least-privilege tool access, compliance posture, and data handling policy. |
Full / Explicit | Full / Explicit |
|
Observability & Auditability Traces, logs, execution histories, metrics, audit events, and debugging detail for production agent behavior. |
Full / Explicit | Partial |
|
Deployment & Data Residency Deployment modes and options, including SaaS, dedicated cloud, VPC, on-prem, hybrid, local runtime, and self-hosting. |
Partial | Full / Explicit |
| Solution readiness | ||
|
Prebuilt Agents, Templates & Packs Ready-made workflows, packaged employees, templates, blueprints, industry solutions, and role-specific agents that reduce time-to-value. |
Full / Explicit | Partial |
| Platform extensibility | ||
|
Model Flexibility & Routing Ability to work across multiple foundation models, route tasks to different models, or let buyers bring their own providers and keys. |
Full / Explicit | Full / Explicit |
|
APIs, SDKs & MCP Extensibility Composability layer: stable APIs, SDKs, MCP tool consumption/serving, custom tools, and integration into internal systems. |
Full / Explicit | Partial |
|
Testing, Debugging & Optimization Testing, debugging, scoring, retries, fallbacks, quality gates, and optimization loops for improving agent workflows before and after deployment. |
Full / Explicit | Full / Explicit |
| Specialist automation | ||
|
Browser & Computer Use Browser, desktop, or remote/local computer control for workflows that cannot be handled through stable APIs alone. |
No / Not documented | No / Not documented |
Pricing snapshot
Sourced from the Index pricing dataset · open each vendor's profile for full detail.
| Pricing | ||
|---|---|---|
|
Entry price Lowest public entry point |
Pay as you go from $0 ($10 free credits); voice engine $0.07 to $0.08/min plus LLM and telephony billed separately; Enterprise custom | Free to build; Starter $29/mo; Ent from $30k/yr |
|
Pricing confidence How public the numbers are |
Public — partial | Public — exact |
|
Billing Primary billing axis |
usage (per minute across voice engine, LLM, and telephony components) | — |
|
Variable cost Workload / overage exposure |
High variable cost | High variable cost |
|
Free tier / trial Try before you buy |
Free tierTrial
|
No free tier
|
|
Buying motion Self-serve vs sales call |
Mixed | — |
Choose Retell AI if
- Engineering owns the voice agent and wants direct API control.
- Transparent per minute economics matter for cost modeling at scale.
- You want to choose and swap the LLM powering conversations.
Choose Synthflow if
- Operations or GTM teams will build and maintain the agents visually.
- Bundled minutes and concurrency in a monthly plan simplify starting out.
- Agency and multi client workflows fit Synthflow's higher tiers.