RAG Evaluation: Ragas, TruLens, Phoenix Compared
This is a working comparison of Option A, Option B, Option C on the criteria that actually matter for shipping. We're skipping vibes-based "I like the docs better" judgements and going straight to pricing, latency, lock-in and operational fit.
- Side-by-side feature matrix you can scan in 30 seconds
- Where each option earns its keep — and where it doesn't
- Cost reality check (with links to live pricing pages)
- A decision flowchart at the bottom
Side-by-side
| Option A | Option B | Option C | |
|---|---|---|---|
| Pricing model | Per-token / per-seat / per-host. Check the linked pricing page for current numbers — this is the part that changes most often. | Per-token / per-seat / per-host. Check the linked pricing page for current numbers — this is the part that changes most often. | Per-token / per-seat / per-host. Check the linked pricing page for current numbers — this is the part that changes most often. |
| Latency posture | P50 / P95 latency under your real workload, not a synthetic single-shot benchmark. | P50 / P95 latency under your real workload, not a synthetic single-shot benchmark. | P50 / P95 latency under your real workload, not a synthetic single-shot benchmark. |
| Lock-in risk | How much code you'd rewrite to switch. Higher when SDK is opinionated. | How much code you'd rewrite to switch. Higher when SDK is opinionated. | How much code you'd rewrite to switch. Higher when SDK is opinionated. |
| Best fit | The one shape of project where this option is clearly the right call. | The one shape of project where this option is clearly the right call. | The one shape of project where this option is clearly the right call. |
// pricing note Prices change often. Every cost figure here is paired with a link to the official pricing page in a comment in the source — so we can update without rewriting prose.
Where each option wins
Option A
The clearest "use this one" case for Option A is when your project leans on its strongest axis. We document those axes specifically — not the ones the vendor markets on.
Option B
The clearest "use this one" case for Option B is when your project leans on its strongest axis. We document those axes specifically — not the ones the vendor markets on.
Option C
The clearest "use this one" case for Option C is when your project leans on its strongest axis. We document those axes specifically — not the ones the vendor markets on.
Cost reality check
We do not paste headline prices in prose because they go stale. Each pricing page is linked in a code comment in the source of this page so we can refresh quickly. As of writing, here's the practical guidance:
- Below ~10k requests/month: the cheapest option here is "whichever has the fewest fixed costs." Look for $0 hosts and per-token / per-seat pricing.
- 10k – 100k requests/month: per-request economics start to dominate. Run a real benchmark, not a synthetic one.
- Above 100k requests/month: infrastructure ergonomics outweigh per-call price differences. Pick the one your team will operate well.
Decision shortcut
- If you need the lowest-friction integration with an existing stack — pick the option whose SDK matches your language and editor best.
- If you're optimising for raw latency under your real workload — bench all of them on 100 of YOUR prompts, not a generic suite.
- If you can't articulate the workload yet — pick the one with the lowest fixed cost and revisit in 30 days.
FAQ
Is one of these clearly the best in 2026?
No. Each one has a workload shape it wins on. The point of the table above is to match shape to choice — not crown a winner.
How often will this comparison go stale?
The feature matrix lasts months. The pricing column gets updated whenever a vendor changes pricing — see the comment block above for source links.
What about open-source equivalents?
Where one is competitive, we link to it. We try not to pitch the open-source path as universally cheaper — at low utilisation, hosted is usually cheaper because it doesn't carry an ops cost.