RateStack vs. Polly
Polly is one of the few modern, well-funded entrants in mortgage pricing. RateStack is a smaller, more focused alternative with deeper investment in the audit substrate and a different integration philosophy.
Trademark used descriptively for comparison (nominative fair use). We describe Polly by its publicly-known category posture; for current product specifics, see Polly. If anything below is inaccurate, please email editorial@ratestack.com and we'll correct it.
Published
Polly and RateStack are the two newer entrants most often considered alongside the established incumbents. Both were built post-2018 with modern architectures and modern integration patterns; both compete directly on the "modernization" thesis.
Where they differ is in priorities. Polly has invested heavily in configurability — letting lenders express complex pricing logic through their UI. RateStack has invested heavily in audit and replay — every quote ships with a per-rule trace, ratesheets are versioned with hash-chained audit, and historical replay reproduces past pricing deterministically.
On the integration side, Polly emphasizes its native LOS and POS integrations. RateStack emphasizes the public API as the integration surface — REST, GraphQL, webhooks with DLQ replay, OpenAPI spec — so any LOS or POS that speaks MISMO can integrate quickly without depending on a custom connector.
Both products are credible choices. The right one for your team depends on whether you weight configurability + native integrations higher (Polly) or audit substrate + open integration surface (RateStack) higher.
Side-by-side
Honest, structured comparison.
How RateStack and Polly compare on the dimensions buyers ask us about most. Cells marked "depends" are configurable in one or both products; verify with each vendor before deciding.
Pricing engine
Multi-mode pricing (BEST_EX / BY_RATE / BY_PRICE)
- RateStack
- Polly
- Depends
Two-stage eligibility (cheap pre-flight)
- RateStack
- Polly
- Depends
Per-rule adjustment trace returned with every quote
- RateStack
- Polly
- Depends
Historical replay (as-of pricing)
- RateStack
- Polly
- Unknown
Three-tier cache with event-driven invalidation
- RateStack
- Polly
- Unknown
Ratesheet automation
Email-in (IMAP) ingestion
- RateStack
- Polly
- Depends
Portal automation (headless browser)
- RateStack
- Polly
- Depends
Excel + PDF + OCR conversion
- RateStack
- Polly
- Depends
Self-learning header-mapping templates
- RateStack
- Polly
- Unknown
Versioned activation with audit
- RateStack
- Polly
- Depends
Audit & compliance
Hash-chained audit log with verify endpoint
- RateStack
- Polly
- Unknown
Pre-write PII redaction
- RateStack
- Polly
- Depends
Published capability catalog (12 ops + 7 provider)
- RateStack
- Polly
- Unknown
SOC 2 Type II
- RateStack
- In audit
- Polly
- Depends
Integrations
Public REST API + OpenAPI spec
- RateStack
- Polly
- Depends
Public GraphQL endpoint
- RateStack
- Polly
- Unknown
Webhooks with HMAC + DLQ replay
- RateStack
- Polly
- Depends
MISMO 3.4 / ULAD import
- RateStack
- Polly
- Depends
Native LOS connectors (Encompass, etc.)
- RateStack
- Depends
- Polly
Native POS connectors
- RateStack
- Polly
- Depends
Counterintuitive
When Polly is the better choice.
We don't pretend to be the right answer for everyone. Here's where we'd point you elsewhere.
Polly is likely the better choice when:
- You want pre-built native LOS / POS connectors. Polly invests in those integrations as a primary feature; if your integration plan depends on a turnkey connector to a specific LOS or POS, ask both vendors what's available today.
- You prefer UI-driven pricing rule configuration over API/data-driven configuration. Both approaches work; Polly has invested more in the UI side.
- You need a venture-funded vendor with broader product breadth. Polly's funding and team are larger than ours.
We're a serious option when explainability + audit substrate + open API surface matter more than pre-built integrations.
If you decide to migrate
What a switch actually looks like.
The realistic timeline, the integration surfaces, the data you'd port over.
Migration from Polly to RateStack is generally straightforward because both products use modern integration patterns. Allow four to six weeks for parallel pricing, shadow production, and cutover.
Specific notes: if you've invested deeply in Polly's native LOS connector, the migration may require new wire-level integration (MISMO 3.4 in either direction). If you're consuming Polly webhooks, the payload shape differs but the logical information content is similar; expect ~1 week of integration work on the consuming side.
Frequently asked
What buyers ask us.
Are Polly and RateStack competing for the same buyer?
Often, yes. Both target lenders looking to modernize off legacy pricing engines. We have different strengths; the right answer depends on your weighting of integration breadth vs. audit substrate. Honest evaluation is welcome — talk to both teams.
Does Polly have a free tier?
Verify with Polly directly; we don't track competitor pricing in real time. RateStack offers a free Sandbox tier with the full feature set and a 100-quote-per-month allowance.
Can I run both during evaluation?
Yes. Run sandboxes from both vendors against your real ratesheets and your top scenarios. Compare the trace fidelity, the integration ergonomics, and the support responsiveness.
Other comparisons
See how we stack up against the rest of the market.
See it on your data
Skip the rest of the comparison shopping.
Show us your top scenarios and your investor pack. We'll run them on a sandbox, walk you through the trace, and tell you honestly whether RateStack is the right choice.