Retell AI

https://www.retellai.com/

Voice agents. Short-term context within call native; long-term memory via webhook integration to CRM / external DB. Cross-agent memory sharing in multi-agent setups.

Active · Verified 2026-10-22 · fresh as of 2026-10-22 · 45 cited facts, 4 with a third-party source · 1 recorded change · Suggest a correction

At a glance

Tier
T2
Created
2024-04 vendor fix
Latest release
not applicable — not OSS fix
License
not applicable — not OSS fix
GitHub
not applicable — no GitHub repo fix
Freshness
2026-10-22 fix
Layer
agent-infra repo fix
Licensing
commercial vendor fix
Deployment locus
cloud vendor fix
Platform vs product
platform vendor fix
Accelerator
yc-w24 third-party fix
SDK languages
python, rest, typescript vendor fix
Protocols
mcp-client, mcp-server vendor fix

Memory taxonomy

storage
kv
retrieval
injection
persistence
cross-session
update
overwrite
unit
episode
governance
inspectable
conflict
none

When to use

Optimised for: low-latency voice + integration-based long-term

Anti-fit: not for non-voice use cases

Pros & cons

Pros

Real-time voice agent platform with memory across calls — strong call-center workflow integration.

Cons

Voice-only; smaller mind-share than Vapi.

Claims & capabilities

Usage-based per minute. Free tier for testing.

Technical surface

API surface
searched not found
Backend storage
searched not found
Deployment
Managed-only (Retell-hosted; Enterprise dedicated-server add-on; no self-host option listed)
Embedding model
searched not found
Multi-tenancy
searched not found
MCP
yes — MCP Node lets agents call tools on external MCP servers mid-call
A2A
searched not found
OpenTelemetry
searched not found

Similar systems

Other framework-embedded memory in the catalog, ranked by inbound references.

  • Spring AI ChatMemory T3

    Wraps conversation memory behind an Advisor abstraction. MessageWindowChatMemory default 20-msg sliding window (preserves system messages); pluggable ChatMemoryRepository backends (in-memory, JDBC, Cassandra, Neo4j). Memory injected as cross-cutting concern at the ChatClient level.

  • Flowise Memory T1

    Discontinued: Flowise (acquired by Workday, Aug 2025) was sunset in 2026 — code freeze 2026-07-29, GitHub repo archived 2026-08-13, end of life 2026-08-31. Was a visual LangChain canvas with LangChain-native memory nodes (Buffer, Buffer Window, Conversation Summary Buffer) backed by an internal chat_message DB table; Buffer Window kept the last K interactions, Summary Buffer compressed older turns while keeping recent ones verbatim.

  • LangGraph Persistence T2

    Distinct from LangMem. Built-in checkpointer saves graph state per super-step (short-term, thread-scoped). Store System adds long-term hierarchical key-value memory across threads with optional vector search + TTL. Postgres / Mongo / Redis stores for production.

  • AutoGen Memory T2

    AutoGen's memory layer: ListMemory chronological context plus teachable agents that vectorise corrections; integrates with Mem0/Zep rather than building deep memory natively. Microsoft AutoGen is in maintenance mode (community managed, bug and security fixes only), and Microsoft points new projects to Microsoft Agent Framework.

  • CrewAI Memory T2

    Memory subsystem inside the CrewAI orchestration framework; integrates with Mem0 for the long-term tier.

  • Hermes Agent memory (Nous Research) T3

    Nous Research's open-source self-improving agent keeps an agent-curated MEMORY.md/USER.md notebook injected at session start, full-text (FTS5) search over past sessions that returns raw messages without LLM summarisation, and optional Honcho user modelling. one of the most-starred agent projects of 2026.

Sources (44 cited facts, 4 third-party)

Each fact links to the page it came from; the badge says who published it (how to read sources).

What changed

Changes to this record's lifecycle, licence, release, pricing and hosting facts, from the catalog's git history. Subscribe (Atom)

  1. 2026-10-22
    • Pricing “Pay-per-use” → “Pay-as-you-go voice $0.07–0.31/min, chat from $0.002/msg, $10 free credits, 20 free concurrent calls (+$8/concurrent call/mo); Enterprise custom” source
    • Deployment “Both” → “Managed-only (Retell-hosted; Enterprise dedicated-server add-on; no self-host option listed)” source
    • MCP support first recorded as “yes — MCP Node lets agents call tools on external MCP servers mid-call” source
    #219