Sim vs Retool
Sim is the open-source AI workspace where teams build, deploy, and manage AI agents visually, conversationally, or with code. Here is how Sim compares to Retool on platform architecture, AI capabilities, integrations, pricing, security, and support. Every fact below is sourced and dated.
Sim is an open-source AI workspace for building, deploying, and managing AI agents. This page compares Sim to Retool across platform architecture, AI capabilities, integrations, pricing, security and compliance, observability, and support, using sourced, dated facts for buyers evaluating both platforms.
What is Sim?
Sim is the open-source AI workspace where teams build, deploy, and manage AI agents, connecting 1,000+ integrations and every major LLM to automate real work visually, conversationally, or with code.
What is Retool?
Retool is a low-code platform for building, deploying, and managing internal software (apps, workflows, and AI agents) that connect to databases, APIs, and LLMs.
Sim vs Retool: feature-by-feature comparison
CompareSim vs Retool
Sim
Retool
Platform
Builder type
Sim
Visual canvas, chat, or codeVisual drag-and-drop canvas, natural-language (Chat), or code (API/SDK)
Retool
Low-code builder with AI-generated starting pointsLow-code/no-code visual app and workflow builder with an underlying React-based app runtime; supports AI-generated ("AppGen") starting points that users then refine visually or by editing generated queries/code.. Retool offers a React-based app builder where you can generate pages, components, and queries from a natural-language description and then edit the underlying logic directly.
Learning curve
Sim
Low, plus natural-language Chat for non-technical usersLow for visual building; natural-language Chat surface (with a workflow-scoped Copilot) for non-technical builders. Chat lets users describe a workflow in plain language and have Sim scaffold or edit it; the visual canvas requires no code to connect blocks.
Retool
Not publicly documentedUnknown. Retool has not published a learning-curve claim.
Self-hosting
Retool
Yes: self-hosted deployment is available on Free, Team, and Business plans at the same pricing as cloud; Enterprise is required for unlimited users and advanced capabilities. A Retool-issued license key is required even when self-hosted.. Self-hosted Retool is deployable via Docker (non-production/testing only) or Kubernetes/Helm (production).
Deployment options
Sim
Cloud-hosted or self-hosted, no mid-tier VPC optionCloud-hosted (managed, multi-tenant SaaS) or self-hosted (Docker/Kubernetes). No documented managed single-tenant/VPC hosting tier in between. The Enterprise plan's only hosting-related row in the pricing comparison table is a boolean "Self Hosting" flag; there is no dedicated-instance/VPC offering.
Retool
Cloud, or self-hosted via Docker/KubernetesRetool Cloud (multi-tenant SaaS), or self-hosted via Docker Compose (non-prod/testing) or Kubernetes with Helm chart (production).
Templates
Sim
License
Sim
Apache 2.0Apache License 2.0
Retool
Closed-source, license key requiredProprietary. Retool is closed-source and proprietary for both cloud and self-hosted versions. The self-hosted codebase can be forked and customized and bundles third-party open-source dependencies, but requires a Retool license key to run.
Environment promotion
Sim
Yes: fork a whole workspace into a dev/qa/prod-style child, diff it, and promote or roll back changes in either direction. Credential and env-var remapping is required before every promote, so secrets are never silently copied across environments. Gated to Enterprise plan on hosted Sim, or a FORKING_ENABLED flag on self-hosted deployments.
Retool
Yes: via Retool Source Control (Git-based) across separate instances/spaces. Source Control lets teams branch an app, open pull requests, and merge changes across dev, staging/QA, and production, running on separate Retool instances (self-hosted Enterprise) or Retool Spaces (Cloud) with per-app control over what syncs. It targets Enterprise/self-hosted customers and requires connecting an external Git provider (GitHub, GitLab, or CodeCommit).
Version control
Sim
Deployment rollback plus Copilot edit diff/revertDeployed-version history with rollback for every workflow; server-persisted checkpoint/revert and visual diff (accept/reject) specifically for Copilot AI edits. Manual drag-and-drop undo/redo is client-side/localStorage only (capped at 100 ops, 5 stacks), not server-synced across devices. Deployment history does not include an arbitrary version-to-version diff tool, and knowledge base documents have no version history.
Retool
Branching, PR review, and release historyBranch-based editing, pull-request review, and release history for controlling which version is live, plus rollback and blue/green deployments.. Source Control supports branch-based editing that isolates changes without overwriting teammates, pull-request review before merging into a live app, and Retool Releases to control which Git commit is live vs draft. No dedicated diff/compare view or client-vs-server undo/redo distinction exists.
Realtime collaboration
Sim
Retool
Yes: Retool Multiplayer lets multiple people edit the same app at once, with live avatars and highlights showing where each teammate is working. It is generally available on Cloud and in beta for self-hosted. Under the hood it uses conflict-free replicated data types (CRDTs) over WebSockets so simultaneous edits merge automatically instead of overwriting each other.. Self-hosted customers must sign up for beta access.
Native file storage
Sim
Yes: a native Files area with folder hierarchy, link-based sharing (public, password, email OTP, or SSO auth), and a workspace-level Recently Deleted view covering workflows, tables, knowledge bases, files, and folders. Admins can restrict which share-auth modes (public/password/email/SSO) a permission group is allowed to use.
Retool
Partial, folders and links yes, no trash/recovery or password links foundPartial: Retool Storage is a native Retool-hosted file store (cloud orgs) supporting folder creation/rename/delete, file rename/move, and link-based access (public URLs or app-scoped private URLs). No password-protected/SSO-gated sharing links or deleted-item/trash recovery mechanism is documented.. Storage caps at a fixed capacity and lacks more advanced sharing and recovery controls.
Native data tables
Sim
Yes: a native spreadsheet-like Tables feature (typed columns, not an external DB connector) with full keyboard support (arrow keys, Tab, copy-paste bulk load, Cmd/Ctrl+Z undo) and atomic per-row writes from multiple workflows at once. No public fixed row-limit figure is documented (guidance says paginate reads past ~100k rows); a workflow can also be wired to run per row via a "workflow column."
Retool
Yes: Retool Database is a real, built-in Postgres-backed database (not a spreadsheet-like store). Tables support foreign-key fields that link rows between tables, and any query can be written in raw SQL (Retool's SQL mode supports arbitrary SELECT/UPDATE/DELETE and other statements, including joins), in addition to a spreadsheet-style Edit Table view for inline editing. Retool's Table UI component separately renders and scrolls through 100,000+ rows and hundreds of columns without slowing down.. Because it's genuine Postgres under the hood, Retool Database supports foreign-key relationships (with configurable on-delete/on-update behavior) and hand-written SQL queries that a typed-column grid like Sim's Tables does not expose; Retool does not publish hard row/column caps for Retool Database itself (forum threads mention plan-dependent limits like 50,000 records, unconfirmed as current). The Table UI component is documented to handle 100K+ rows.
Rich-text document editor
Sim
Retool
No, native editor is HTML-input, not WYSIWYG markdownNot true WYSIWYG editing: Retool's Rich Text Editor component lets users type HTML-formatted text, and a separate Text component displays Markdown, but neither is a full WYSIWYG Markdown editor. Community members have built custom components (based on the CKEditor library) to get true WYSIWYG Markdown editing.. Multiple long-running Retool forum feature requests ask for WYSIWYG markdown editing, still unresolved.
Sub-workflows (composition)
Sim
Retool
Yes: the Workflow block runs another saved workflow as a step, passing data to it and receiving its returned data back, so the parent workflow can compose child workflows rather than duplicating logic.. The Workflow block supports two execution modes: Finished, where the calling workflow pauses until the triggered workflow run completes, and Queued, where the calling workflow continues immediately while the triggered run is queued.
Custom blocks (org-wide reuse)
Sim
Yes: a user with admin access on a workflow's workspace can publish its deployed version as a named, iconed custom block that appears in the block toolbar for the whole organization. Inputs are read live from the source workflow's Start block; the publisher picks which outputs to expose. The block always runs the source workflow's latest deployed version, and its internal steps and intermediate values are never exposed to consumers. Enterprise-gated on Sim Cloud; self-hosted deployments can opt in via a feature flag. Distinct from the Workflow (sub-workflow) block, which composes a workflow the same author controls, and from custom code/tool blocks, which run inline code rather than a full deployed workflow.
Retool
No: Retool has no way to publish a deployed workflow as a named, encapsulated block that shows up in a shared block library for other builders to drop into their own workflows. The closest primitive is the generic Workflow block (see subWorkflows), which requires manually selecting which saved workflow to call each time it is added, rather than appearing as its own distinct, iconed, org-wide toolbar entry. A public forum feature request asking for exactly this ("Workflow Block Library," save a block once and reuse it across workflows) is still open, with a Retool team member confirming only an internal, unshipped feature request exists for it.. The Workflow block abstracts away the called workflow's internal steps, but it is one generic block type, not a per-source-workflow custom block, and Retool's docs do not document automatic org-wide distribution or live-sync-to-latest-deploy behavior the way a dedicated published-block feature would.
Pricing
Pricing model
Sim
Credit-based billing, BYOK exempt from capsCredit-based usage billing (Stripe), with bring-your-own-key exemption from metered caps
Retool
Seat-based plus AI credits and hourly Agents billingSeat-based (separate builder vs. end-user/internal-user seat prices) plus pooled monthly AI-credit allocations and separately metered hourly billing for Agents usage.
Entry paid plan
Sim
Pro plan at $25/user/monthPro: $25 per user/month
Retool
$10/builder + $5/user per month (Team plan)Team plan: $10/builder/month and $5/internal-user/month (annual billing; $12/$7 monthly), including 5,000 workflow runs/month, staging environment, app release versions, and 1,000 AI credits/month.
Free tier
Sim
Bring your own key
Sim
Retool
BYO chat model, but embeddings always use OpenAIPartial: Retool AI supports "bring your own" model connections for chat/completion models (OpenAI, Anthropic, Google, AWS, Azure, or custom), but Retool Vectors' embedding calls always go through OpenAI's API regardless of the chosen chat model.
Security & compliance
SOC 2
Data residency
Sim
Full control via self-hosting; Cloud region toggle is global, not per-customerFull data control via self-hosting (Docker/Kubernetes); data never leaves customer infrastructure when self-hosted. On Sim Cloud, async job execution has an internal US/EU region toggle, but it is deployment-wide, not a customer-selectable per-workspace residency option
Retool
AWS-hosted (cloud); no data stored self-hostedCloud: customer data stored redundantly across multiple AWS data center locations (no customer-selectable region specified). Self-hosted: no Retool systems store customer data and no Retool personnel have technical/logical access to it.
Role-based access control
Sim
Yes: admin/write/read workspace permissions, org-level admin/member roles, plus Enterprise-tier permission groups that allow/deny-list specific models, tools, and integrations per group on top of those base roles. See modelAndToolGovernance and credentialGovernance for the finer-grained permission-groups layer.
Audit logging
Sim
Retool
Yes: available starting on the Business plan (audit logging listed as a Business-tier feature), with expanded audit logging on Enterprise; Enterprise orgs can also continuously stream audit log events to Datadog, or output them to stdout for ingestion by any external pipeline on self-hosted deployments.. Cloud Business/Enterprise can additionally download audit logs from the UI in batch. No direct S3/BigQuery/generic-webhook drain is documented; Datadog streaming and self-hosted stdout are the only continuous-export mechanisms Retool publishes.
Additional compliance
Sim
SOC2SOC2. Self-hosting is the primary lever Sim offers for data-residency-sensitive compliance needs beyond SOC2, rather than additional certifications.
Retool
SOC 2, ISO 27001, GDPR, CCPA; HIPAA via BAASOC 2 Type II, ISO/IEC 27001:2022, GDPR, and CCPA certifications, plus HIPAA via BAA on Enterprise.. The Trust Center (SafeBase-powered) lists SOC 2 Type 2, ISO/IEC 27001:2022, GDPR, and CCPA certifications. HIPAA compliance is available with a signed BAA on Enterprise (self-hosted) plans. PCI and FedRAMP are not confirmed.
Model & tool governance
Sim
Yes: enterprise "permission groups" let an admin allow-list/deny-list specific LLM providers and models, and separately deny specific tools/integrations (or disable all MCP or custom tools) per group, layered on top of workspace admin/write/read roles. This does not control whether an LLM provider retains prompts. Sim offers no "zero data retention" mode or governed AI gateway. A separate, Enterprise-gated feature lets orgs set a log-retention window and redact PII, but that only controls how long Sim itself keeps execution logs.
Retool
Not publicly documentedUnknown. Not publicly documented.
Credential governance
Sim
Yes: shared credentials (connected accounts, service accounts, workspace secrets) are their own nested permission level (Member/Admin) below organization and workspace roles, and enterprise permission groups can further allow-list specific integrations and restrict which file-share auth modes (public/password/email/SSO) a group may use. A user's personal environment variables/secrets are never shared or inherited by anyone, including org owners/admins.
Retool
Yes: Retool (Business/Enterprise plans) supports resource-level permissions with Use, Edit, and Own tiers. Enterprise orgs can go further and set per-environment permissions on the same resource (for example, allow Use on staging credentials but deny production credentials), independent of feature-level RBAC.. Permission control for Resources (Use/Edit/Own tiers) is available starting on the Business plan; per-environment override, selecting 'Define specific resource access' on a resource, is an Enterprise-only capability.
Single sign-on (SSO)
Sim
Retool
Yes: Retool supports SAML 2.0 SSO and Custom SSO (Okta, Azure AD/Entra ID, Google Workspace, OneLogin, and other SAML/OIDC providers) — but only on the Enterprise plan, not Business. SCIM-based auto-provisioning is available on Cloud or self-hosted 2.32.1+.. Retool's current pricing page places SAML/Custom SSO exclusively on the Enterprise tier; the Business plan's feature list does not include SSO/SAML.
Vetted first-party integrations
Sim
Yes: every one of Sim's 266 blocks is first-party authored and code-reviewed through the standard pull-request process in the main Sim repository; there is no public marketplace where an arbitrary third party can publish and have other users install executable tool code without going through Sim's own review. Custom code steps run inside Sim's own isolated-vm sandbox rather than as an installable third-party skill package, so the supply-chain trust boundary is Sim's codebase review, not an open registry.
Retool
Yes: Retool's built-in integrations (Resources) are a first-party catalog of roughly 90+ databases, APIs, AI services, and cloud tools built and maintained by Retool, not an open marketplace of third-party-submitted connectors. Custom Component Libraries let a customer's own developers pull in npm packages to build custom UI components, but these are private to the authoring organization by default, not a shared registry of code from unrelated third parties.. A custom component loads into a sandboxed iframe, and Retool's custom-component-guide plus a community forum thread ('Custom Component Vulnerabilities') flag that developers should run npm audit on dependencies pulled into their own component libraries. This is a supply-chain caution for self-authored code, not an incident involving a shared marketplace, since no public component marketplace exists.
PII redaction
Sim
Retool
No: Retool has no automated PII-detection or redaction system for workflow content or logs. The closest control is the manual, per-query 'Remove parameters from logs' option in Advanced Options, which lets a builder exclude specific named parameters (which could include PII) from being written to audit logs. This is manual exclusion, not automatic PII detection or redaction.
Custom data retention
Sim
Retool
No: Retool Cloud has a fixed one-year audit log retention with only the most recent three months browsable in the UI; there is no documented org-configurable retention window on Cloud. Self-hosted orgs manage retention themselves via their own infrastructure, but that is operator-managed, not a Retool-provided configurable setting.. No configurable retention windows exist for other resources, like soft-deleted items, either.
White-labeling
Sim
Retool
Yes: Retool's Enterprise plan includes full white-labeling, letting orgs replace the Retool logo/favicon and remove references to the Retool name across login pages, headers, invite/password-reset emails, and app presentation mode. The Business plan gets custom branding with fewer white-label controls. Separately, white-labeled Retool Mobile apps can be requested for the iOS/Android app stores.. Custom domain (Business/Enterprise) is required alongside white-labeling for a fully de-branded experience.
AI capabilities
Multi-LLM support
Sim
21 providers plus dynamic-resolution aggregators (OpenRouter, LiteLLM, etc.)21 provider integrations (OpenAI, Anthropic, Google/Gemini, Azure OpenAI, Azure Anthropic, Groq, Cerebras, Mistral, xAI, Bedrock, Vertex, Ollama, OpenRouter, and more), with OpenRouter, LiteLLM, vLLM, and Ollama resolving models dynamically at runtime rather than from a fixed list, so effective model reach extends well beyond the 21 named providers. apps/sim/providers/models.ts defines 21 provider entries.
Retool
OpenAI, Anthropic, Google, Bedrock, Azure, or BYO modelDirect providers OpenAI, Anthropic, and Google; cloud service providers AWS (Bedrock) and Azure (OpenAI); plus a "bring your own model" option.. Retool lists these categories without enumerating specific model versions.
Agent reasoning blocks
Sim
Natural-language building
Knowledge base / RAG
Sim
Yes: hybrid vector (pgvector) plus full-text (tsvector) search knowledge base, 11 supported file formats (csv, doc, docx, html, json, md, pdf, pptx, txt, xlsx, yaml), configurable chunking, plus 51 connectors that continuously sync external sources (Google Drive, Confluence, Slack, Gmail, GitHub, HubSpot, Linear, Jira, and more) into the knowledge base rather than a one-shot upload
MCP support
Sim
Retool
Evaluation & guardrails
Sim
LLM-judge Evaluator plus Guardrails validation blockEvaluator block (LLM-judge scoring against user-defined named metrics) and Guardrails block (JSON validity, regex, RAG/hallucination scoring, PII detection/masking). These are per-call scoring/validation primitives, not a batch golden-dataset eval-suite runner or A/B prompt-testing harness.
Retool
Access/audit controls only, no eval frameworkPartial: Retool provides governance-style guardrails, enterprise access controls, monitoring, and audit trails for agent and workflow actions, but no dedicated evaluation or test-suite framework for validating AI output quality.. Retool's guardrails are access and observability controls (enterprise access controls, monitoring, and audit trails), not a dedicated evals product.
Human-in-the-loop
Sim
Retool
Yes: dedicated human-in-the-loop approval tasks distinct from a delay/wait step. Retool Agents and Workflows support an auditable, permissionable approval task that must be approved by one or more people in a designated permission group before a run proceeds (for example, reviewing an agent's proposed tool call or action). Approvers can be notified via Retool app/task assignment or Slack/email through workflow blocks. The run resumes automatically once the decision is recorded, and every step is logged to the audit trail.
Generative media
Sim
Retool
Image generation only, no video/TTS/STTNative image generation only. No native video generation, text-to-speech, or speech-to-text block.. Retool's AI query block includes a native "Generate image" action (model options: GPT Image 1, GPT Image 1 Mini, and GPT Image 1.5, all via OpenAI) that returns a base64-encoded image. There is no native video-generation, text-to-speech, or speech-to-text block; users build these via third-party APIs.
Dynamic tool use
Sim
No: an Agent block calls tools the workflow author explicitly added to it at build time, rather than browsing and picking from a broader pool (e.g. an entire MCP server catalog) at inference time. Runtime MCP "discovery" exists to resolve/refresh the schema of an already-configured tool. The model does not browse or choose from the server's full tool list.
Retool
Not publicly documentedUnknown. Not publicly documented.
Automatic model fallback
Sim
No: a failed or rate-limited LLM call is retried using Sim's own hosted API keys for the same model, rather than automatically switching to a different model or provider. A "fallback" comment in the provider layer refers to rotating among Sim's own hosted API keys for the same model, not switching models.
Retool
Not publicly documentedUnknown. Not publicly documented.
Agent skills
Sim
Yes: named, reusable "Agent Skills" (built on the open Agent Skills / SKILL.md format) that agents load on demand via progressive disclosure, editable in-app or imported from a SKILL.md file or GitHub URL. Only the skill name and description sit in the agent's system prompt (~50-100 tokens each); the full instructions load into context only when the agent calls load_skill.
Retool
Unknown, no shared skills-library feature foundUnknown: Retool has no feature for defining a reusable, named prompt or knowledge snippet once and reusing it across multiple agents by reference. Retool's agent docs describe per-agent instructions and system prompts, plus connecting Resources, Vectors, and MCP servers as tools, but not a shared 'skills library' construct.. Retool has reusable components and shared primitives for apps and workflows generally, but nothing matches a cross-agent named prompt-snippet system, the kind Anthropic and Replit call 'Agent Skills'.
Native chat deployment
Sim
Retool
Estimated yes, via Agent Chat component embedded in appsEstimated yes: Retool Agents include a chat interface for testing and interacting with an agent, and can be embedded into deployed Retool apps via an Agent Chat component, giving end users a conversational surface, alongside other deployment targets like email and workflows/API. A public 'share thread' replay link also exists for individual conversations.. Chat is delivered by embedding the Agent Chat component in a publicly-shared app rather than a single-click standalone public chat deployment; there is no dedicated one-click public chat endpoint.
Parallel execution
Sim
Yes: a native Parallel block fans a run out into concurrent branches (fixed count or one per list item) and joins their results back into the workflow automatically. Contained blocks run concurrently instead of sequentially, either a fixed number of times or once per item in a list/collection, and each branch's output aggregates for downstream blocks.
Retool
Yes: Retool Workflows has a Branch block that outputs to multiple downstream blocks, creating separate paths that run at the same time, and a Loop block with a dedicated parallel execution mode for concurrent iteration. A block with multiple incoming connections waits for all of them to finish before running, which is how parallel paths join back together. Some older community forum reports describe blocks executing sequentially rather than concurrently in certain cases, so real-world concurrency may vary from the documented behavior.. Official docs describe multi-output blocks and a Loop block parallel mode; a small number of community forum threads report inconsistent concurrent execution in practice.
Agent2Agent (A2A) protocol
Sim
Retool
Yes: Retool documents native Agent2Agent (A2A) protocol support for Retool-built agents, including agent cards, sending messages, polling for task updates, and streaming updates over Server-Sent Events. Support is ingress-only (external agents can call a Retool agent, not the reverse), limited to the HTTP+REST and JSON-RPC transports, and authenticates callers with an API key header rather than delegated auth.. Retool docs describe this as "the core set of A2A functionality" and explicitly note the input-required and auth-required task states are not supported, so tools requiring delegated authentication or approval will fail over A2A.
Loop / iteration block
Sim
Retool
Yes: a dedicated Loop block runs an embedded set of blocks once per item in an array, referencing each item and its index via value and index.. The Loop block supports Sequential mode (each iteration completes before the next starts, with an optional delay to avoid rate limits), Parallel mode (all iterations run simultaneously), and Batch mode (a configurable number of iterations run in parallel per batch, default batch size 10) before moving to the next batch.
Integrations
Integrations
Sim
1,000+ integrations (266 blocks, ~3,900 tool actions)1,000+ integrations counting individual API actions, built from 266 first-party blocks and roughly 3,900 underlying tool actions. Sim's landing page cites the "1,000+ integrations" figure; the block/tool-action counts are the same integration surface measured at a different level of granularity.
Retool
90+ connectors plus REST/GraphQL/gRPC90+ listed integrations/connectors on the public integrations page, plus generic REST API, GraphQL, and gRPC connectivity for anything without a native connector.. Categories include databases, cloud platforms, CRMs, messaging, and AI services (OpenAI, Anthropic, Google Gemini, etc.).
Trigger types
Sim
Webhook, cron, chat, REST API, 61 app triggers, plus a diff-aware Tables triggerWebhook, schedule/cron, chat, REST API, and event-based triggers for 61 apps (Slack, Gmail, GitHub, Stripe, etc.), plus a native row-level trigger on Sim Tables that fires on insert/update with an optional column watch-list and emits a before/after diff
Retool
Not publicly documentedUnknown. Not documented in a single consolidated reference.
Custom code steps
Retool
Not publicly documentedUnknown. Not publicly documented.
API publishing
Sim
Yes: a public REST API (mostly under /api/, with /api/v1 reserved for logs and audit-log endpoints) supporting API-triggered workflow execution and deployment rollback. The API reference does not document SSE streaming, a resumable event buffer, a dedicated API-trigger block, or a chat-deployment surface as part of the REST API itself.
Retool
Enterprise platform APIs plus MCP server accessEnterprise plan includes "platform APIs" for managing/orchestrating Retool resources; Retool itself can also be exposed as an MCP server for programmatic/agent access.. Platform APIs are an Enterprise-tier pricing feature. Retool has not published whether individual apps or workflows can be published as standalone REST endpoints.
SDKs & extensibility
Sim
Official Python and TypeScript SDKs, plus MCP, code block, and A2A protocolOfficial client SDKs exist for Python (simstudio-sdk, pip install simstudio-sdk) and TypeScript/JavaScript (simstudio-ts-sdk, npm install simstudio-ts-sdk), both wrapping the REST API (x-api-key header) with methods like execute_workflow / executeWorkflow, retry-with-backoff, and usage-limit lookups. Extensibility is further extended by MCP (client + server), a sandboxed code-execution block (JS/Python), custom tools, and an Agent-to-Agent (A2A) protocol block for external agent interop
Retool
Custom Component React/TS kit, no multi-language SDKCustom Component dev kit (React/TypeScript) + CLI, plus a community Custom Component Gallery; no general-purpose client SDK for multiple languages found. Retool provides a TypeScript API for building custom React components locally (using standard npm packages and Retool's `retool-ccl` CLI tool) that adds new properties and events to the app editor. Finished components can be published to the community Custom Component Gallery or shared privately as component libraries. There is no multi-language client SDK, such as Python, Node, or Go REST client libraries, beyond this TypeScript toolkit and workflow webhook/REST triggers.
Publish as MCP server
Sim
Retool
No, not in the sense of turning one specific app into its own callable tool: Retool's MCP server (public beta) exposes Retool's own build and management actions (create/edit apps, run queries, manage users, inspect resources) so external AI tools like Claude or Cursor can operate the Retool platform itself. It does not let you publish a single deployed app or workflow as its own standalone MCP tool for outside consumption.. Retool agents can call external MCP servers as tools, and Retool itself is an MCP server for managing the workspace, but no documentation confirms publishing an individual workflow or app as its own MCP endpoint for external tool-calling.
Observability & durability
Tracing & observability
Sim
Yes: execution logs include a per-block/per-span trace view (duration, cost, token counts, and latency stats like TTFT/TPS) with expandable nested iteration groups, plus a "View Snapshot" frozen copy of the workflow structure and block states at run time for debugging. This trace view is built directly into Sim rather than a raw export browsable in an external tool like Jaeger, and does not expose aggregate latency-percentile charts (p50/p95/p99). The run snapshot serves as a log-detail/debugging artifact rather than a resumable mid-run checkpoint.
Retool
Block-level run logs; tracing via Datadog/SentryPer-run/per-block execution logs and status in Run History; no native distributed tracing with spans. Latency percentile and error-rate dashboards require connecting Datadog or Sentry.. Run History lists every workflow run with date/time/status and lets you drill into each block to find where a failure occurred, filterable by error/success/info. This is block-level status logging, not distributed tracing with spans. For latency percentile or error-rate dashboards, Retool points to connecting an external tool like Datadog or Sentry rather than offering a built-in metrics dashboard.
Durability & retries
Sim
Tool-call retries (up to 10x); single-attempt job orchestrationIndividual tool/API calls have configurable exponential-backoff retry (up to 10 attempts). The background job-orchestration layer itself retries only once by design. Durability instead comes from consecutive-failure tracking on schedules and the human-in-the-loop snapshot pause/resume mechanism. Sim does not offer guaranteed-once-only block execution, a failed-run holding queue for manual recovery, or a "replay a past execution with its original inputs" feature. The per-execution debugging snapshot serves as a log-detail artifact rather than a resumable mid-run checkpoint.
Retool
Configurable retries with backoff; no checkpointingAutomatic retries with configurable schedules and exponential backoff. No durable checkpointing or one-click replay of a past execution with its original inputs.. Workflows can configure error handlers to automatically retry failed blocks on a schedule, including exponential backoff for rate-limited APIs/data sources, plus block-level and global error handlers for unhandled errors. There is no durable checkpointing of workflow state or one-click replay of a past execution with its original inputs beyond re-running/retrying.
Failure alerting
Sim
Retool
DIY via error handlers, no built-in alertingAlerting is DIY. Built via error-handler blocks wired to Slack/email/notification actions. No built-in proactive alert or cost/latency-threshold subscription system.. Retool Workflows exposes `workflowContext.currentRun.error` inside an error handler block, which builders commonly wire to a Slack or email notification action to be proactively notified of a failed run. There is no native cost/latency-threshold alerting feature (e.g., an admin setting an alert for runs exceeding a cost or duration threshold); this is typically DIY via error handlers.
Data drains
Sim
Yes: Enterprise orgs can continuously export workflow logs, job logs, or audit logs on a schedule to a customer-owned S3 bucket, GCS bucket, Azure Blob container, BigQuery table, Snowflake table, Datadog logs intake, or an HTTPS webhook. Each drain exports exactly one data source; multiple drains are created to export multiple sources. Viewing drain config/run history is restricted to org owners/admins.
Retool
Yes: Retool Enterprise orgs (Cloud or self-hosted 3.38 Edge+) can continuously stream audit log events to Datadog, and self-hosted deployments can set LOG_AUDIT_EVENTS=true to output all audit events to stdout for ingestion by any external log pipeline.. Cloud Business/Enterprise can also download audit logs from the UI (batch, not a live drain). No direct S3/BigQuery/generic-webhook drains are documented; Datadog and self-hosted stdout are the documented mechanisms.
Async execution
Sim
Yes: a workflow can be triggered in fire-and-forget async mode, returning HTTP 202 with a job ID immediately, then polled via a dedicated jobs endpoint through queued/processing/completed/failed states. Async jobs are tracked via polling the job endpoint rather than a completion webhook/callback option.
Retool
Yes: Retool workflows triggered via their webhook URL (the same api.retool.com/v1/workflows/{id}/startTrigger endpoint used for classic-app and API triggers) can run asynchronously. If the workflow has no Response block, it is enqueued for asynchronous execution and responds immediately; if it has a Response block, it responds synchronously up to that block and the rest of the run continues asynchronously afterward. Retool's own docs define a 30-hour timeout for 'asynchronous workflow runs' versus 15 minutes for 'synchronous workflow runs' (bound to the first Response block). Run status can optionally be checked via the Get Workflow Run Details endpoint, currently in private beta (Retool 3.122+, requires a 'Workflows > Read' API token scope, access by request).. The enqueue-and-respond-immediately behavior for Response-block-less runs is documented specifically for classic-app-triggered workflows, which fire through the same webhook/startTrigger mechanism as API-triggered ones. The Get Workflow Run Details API to fetch a run status/result after triggering is gated behind a private-beta signup, not generally available.
Execution limits
Sim
5-50 min sync timeout, 90 min async, 10-1,000 concurrentPlan-gated: synchronous API calls time out at 5 minutes on the free plan and 50 minutes on paid plans, async calls at 90 minutes on every plan, with 10 to 1,000 concurrent executions per billing account depending on plan. Concurrency limits are published in the platform cost docs, and Enterprise limits are customizable. Request bodies are separately capped at 10 MB.
Retool
Yes: Retool publishes concrete execution limits. Synchronous workflow runs (blocking until the first webhook Response block) time out after 15 minutes; asynchronous runs time out after 30 hours, though workflows with a User Task or Wait block can run indefinitely (individual Wait blocks still cap at 60 days). Resource and query blocks can run up to 2 minutes in sync mode or up to 10 minutes in async mode (Cloud). Concurrency is capped at 50 in-flight outbound requests per workflow and 100 concurrent workflow runs on Retool Cloud, with a burst allowance of 200 runs in a 10-second window, and each run can use up to 2.5GB of memory.. Self-hosted customers can raise the 50 in-flight request cap via the WORKFLOW_REQUEST_CONCURRENCY_LIMIT env var, and memory enforcement (2,500 MB default) is opt-in via WORKFLOW_MONITOR_PROCESS_ENABLED.
Partial-failure handling
Sim
Retool
Yes: Retool Workflows let a failing block route to a dedicated error-handling path while the rest of the run continues, rather than always halting the whole execution. Each block has a red 'On Error' connector you can wire to a downstream handler block, and workflow-level (global) error handlers catch any unhandled errors from blocks that don't have their own On Error connection.. Global error handlers only fire for blocks lacking a block-level On Error connection, avoiding double handling; error details are exposed at workflowContext.currentRun.error for logging.
Unattended execution
Sim
Yes: scheduled, webhook, and chat-triggered runs execute as background jobs on trigger.dev workers, entirely on Sim's servers. No client device needs to be open, awake, or connected for a run to fire or complete; closing the browser tab or shutting down a laptop has no effect on a scheduled or triggered workflow.
Retool
Yes: scheduled and webhook-triggered Retool Workflow runs execute entirely on Retool's servers (Cloud) or the self-hosted deployment's own infrastructure, not on a builder's browser or device.. A triggered run continues executing after the initial request returns and can be polled later via the Get Workflow Run Details API, exactly as documented for asynchronous runs. No client device needs to stay open, awake, or connected for a scheduled or webhook-triggered run to fire or complete.
Support
Support channels
Sim
Community support plus Enterprise 'Dedicated Support'Community (open source, GitHub) plus an unquantified "Dedicated Support" flag on the Enterprise plan. Enterprise and pricing pages do not include CSM, onboarding/enablement, or professional-services details beyond a plan-comparison-table "Dedicated Support" flag.
Retool
Breakage form/forum/office hours for all; dedicated portal on EnterpriseA 'Report a Breakage' form and billing/account email support (all customers, 2-business-day response), a Developer Forum and weekly office-hours Zoom calls with Community Engineers, and a Reddit community; a dedicated Enterprise Support Portal with response times per the Enterprise Support Policy is available for Enterprise customers.. No Team-tier email+chat or Business-tier dedicated support, and no Slack group for 'Power Users', is currently documented.
SLA
Sim
Retool
Support Engineering + technical advisor on EnterpriseEnterprise plan includes Retool's Support Engineering team for technical support and access to a dedicated technical advisor for onboarding, training, and guidance.. The pricing page does not explicitly reference a named 'custom SLA' or 'account management' service.
Community
Sim
100,000+ buildersOver 100,000 builders use Sim
Retool
Active Discourse forum (190K+ posts), no public star/member countCommunity Discourse forum with 190,000+ posts across 22,900+ topics and 17,000+ registered users. No GitHub star count or Slack member count is publicly disclosed.. Aggregate forum stats come from Retool's public Discourse instance stats endpoint rather than a published Retool metrics page.
Academy / training
Sim
Retool
Yes: Retool University (university.retool.com) launched with five course paths (Fundamentals, Platform Developer, Platform Admin, Platform Architect, Platform Advanced Developer), with most courses awarding a digital badge on completion, and a live Retool Platform Developer badge is issued via Credly.. Retool's education docs (docs.retool.com/education) have since been reframed around AI Apps, Workflows, and Agents rather than these named course paths, though the original five-path structure and Credly badges remain live via university.retool.com and the announcement blog post.
Sim standout features
AI Copilot / Chat agent-building surface
Chat builds and manages work across the workspace; in-editor Copilot edits a single workflow.
A workspace-wide natural-language surface (Chat) that can build workflows, manage data, and take actions across integrations, plus an in-editor Copilot scoped to building and editing a single workflow directly.Hybrid semantic + keyword knowledge base
Combines vector and full-text search with configurable chunking across 11 file formats.
Built-in RAG with pgvector embeddings and a generated tsvector column for combined vector + full-text search, plus a token-based chunker with configurable chunk size/overlap and 11 supported file formats (csv, doc, docx, html, json, md, pdf, pptx, txt, xlsx, yaml).Native MCP client and server
Call external MCP servers as tools, or expose Sim workflows as an MCP server.
A dedicated MCP block lets any workflow call external MCP servers as a tool, and a serve/workflow-servers API surface lets Sim expose its own workflows as MCP servers.Fork a workspace into dev, qa, and prod environments
Fork, diff, and promote environments with mandatory credential remapping.
Fork a whole workspace into a dev/qa/prod-style child environment, preview a diff, and promote changes bidirectionally. Credential and env-var remapping is required on every promote, so secrets never cross environments silently.Human-in-the-loop approvals with durable resume
Pause a run for human approval and resume later via a durable snapshot link.
A dedicated block pauses a run and waits for a human-submitted approval form, backed by persisted execution snapshots so the run can resume later via a link, even after a server restart.Self-hostable under Apache 2.0
Fully open source with Docker Compose and Helm deployment options.
Fully open source (Apache 2.0), with Docker Compose files and a Helm chart for Kubernetes deployment, alongside a managed cloud-hosted option.Live multiplayer canvas editing
Real-time cursors, selections, and synced edits on the same canvas.
Real-time cursors, selection broadcasting, and synced concurrent edits over a dedicated realtime backend, so a team can build the same workflow together at the same time.Documented Retool limitations
Proprietary, closed-source core
Closed-source product; self-hosted still requires a Retool license key.
Retool is proprietary and closed-source. The self-hosted deployment can be forked and customized and bundles open-source dependencies, but still requires a Retool-issued license key to run. No OSS license covers the product itself.Docker self-hosted deployment explicitly not production-ready
Docker Compose setup is for testing only; production needs Kubernetes/Helm.
The Docker Compose self-hosted setup (bundled Postgres container, no SSL configured) is for local and non-production testing only. Production self-hosting requires a Kubernetes/Helm deployment.No dedicated built-in eval/guardrail framework documented
No dedicated evaluation or guardrail framework for AI output quality.
Retool documents governance controls (audit logs, RBAC, enterprise access controls) but no dedicated evaluation, testing, or guardrail framework for validating AI agent behavior or outputs before production use.Agents billed separately by the hour, outside the AI-credit pool
Agents usage is billed hourly, separate from the AI-credit pool.
Retool Agents usage is metered and billed hourly, separate from the monthly AI-credit allocation used for app-building and AI actions. This adds a second, less predictable usage-based cost on top of seat pricing.Bottom line
Choose Sim if you want an open-source, self-hostable AI workspace that treats AI agents as first-class citizens: native multi-LLM support, real-time multiplayer editing, environment promotion (dev/qa/prod), human-in-the-loop approvals, and enterprise governance (SSO, credential-level permissions, audit logs) built in rather than bolted on.
Choose Retool if you specifically need full internal business applications, not just agent workflows: Retool builds full internal business applications, not just agent workflows: apps are now written in React on the frontend and TypeScript on the backend, giving teams a real app runtime instead of a proprietary component tree. AppGen lets users describe an app in plain English; Retool's agent generates the UI, data queries, and bindings from that prompt, wired to production data, with every generated app automatically inheriting the org's existing centralized authentication, role-based access controls, and data-access policies rather than having auth logic baked into the app code.
Frequently asked questions
Sim is an open-source AI workspace where teams build, deploy, and manage AI agents visually, conversationally, or with code. Retool is a low-code platform for building, deploying, and managing internal software (apps, workflows, and AI agents) that connect to databases, APIs, and LLMs. Teams considering a switch typically weigh licensing (Sim is Apache 2.0 and self-hostable), pricing model, and how AI-native the platform's agent-building experience is.