LLM observability: what 500,000 traces costs
Observability tools bill different units. This table treats one request as one unit; real span counts will be higher.
Scenario. $0 a month of list-price tokens, 500,000 logs, 5 seats, own keys. Ordered by total bill, lowest first. Not a quality ranking.
Pydantic Logfire$0
- Token markup: $0
0% of $0 list-price spend - Funding fee: $0
Own keys: 0% fee - Platform: Personal: $0
free tier or no platform fee
Pydantic pricing page OFFICIAL 2026-11-10
- Token markup: $0
Opik (Comet)$39
- Token markup: $0
0% of $0 list-price spend - Funding fee: $0
Own keys: 0% fee - Platform: Pro Cloud: $19
$19 a month
Comet pricing page (Opik) OFFICIAL 2026-11-10 - Log usage above allowance: $20
400,000 extra ÷ 100,000 × $5
Comet pricing page (Opik) OFFICIAL 2026-11-10
- Token markup: $0
Langfuse$61
- Token markup: $0
0% of $0 list-price spend - Funding fee: $0
Own keys: 0% fee - Platform: Core: $29
$29 a month
Langfuse pricing page OFFICIAL 2026-11-10 - Log usage above allowance: $32
400,000 extra ÷ 100,000 × $8
Langfuse pricing page OFFICIAL 2026-11-10
- Token markup: $0
Confident AI$200
- Token markup: $0
0% of $0 list-price spend - Funding fee: $0
Own keys: 0% fee - Platform: Starter: $200
$200 a month
Confident AI pricing page (Free $0, Starter $200, Team $2,000; $1 per GB-month over) OFFICIAL 2026-11-10
Not in this total: Vendor conversion: ~100K traces ≈ 1 GB; assumes 1-month retention.
- Token markup: $0
Datadog LLM Observability$300
- Token markup: $0
0% of $0 list-price spend - Funding fee: $0
Own keys: 0% fee - Platform: Pro (annual billing): $160
$160 a month
Datadog pricing page (Pro "Starting At $160 per month", annual pricing shown; $3.50 per 10K extra) OFFICIAL 2026-11-10 - Log usage above allowance: $140
400,000 extra ÷ 10,000 × $3.5
Datadog pricing page (Pro "Starting At $160 per month", annual pricing shown; $3.50 per 10K extra) OFFICIAL 2026-11-10
Not in this total: Pro is $160 a month billed annually ($200 month-to-month, $240 on-demand) for the first 100K LLM spans; $3.50 per 10K extra billed annually.
- Token markup: $0
Fiddler$1,000
- Token markup: $0
0% of $0 list-price spend - Funding fee: $0
Own keys: 0% fee - Platform: Developer ($0.002 per trace): $0
free tier or no platform fee
Fiddler pricing page ($0.002 per trace) OFFICIAL 2026-11-10 - Log usage above allowance: $1,000
500,000 extra ÷ 1 × $0.002
Fiddler pricing page ($0.002 per trace) OFFICIAL 2026-11-10
- Token markup: $0
Prefactor$1,199
- Token markup: $0
0% of $0 list-price spend - Funding fee: $0
Own keys: 0% fee - Platform: Scaleup: $199
$199 a month
Prefactor pricing page (Dev free 5,000 spans; Startup $49, 15,000 spans, $0.0025/span; Scaleup $199, 100,000 spans, $2.50/1k) OFFICIAL 2026-11-10 - Log usage above allowance: $1,000
400,000 extra ÷ 1,000 × $2.5
Prefactor pricing page (Dev free 5,000 spans; Startup $49, 15,000 spans, $0.0025/span; Scaleup $199, 100,000 spans, $2.50/1k) OFFICIAL 2026-11-10
- Token markup: $0
LangSmith$2,645
- Token markup: $0
0% of $0 list-price spend - Funding fee: $0
Own keys: 0% fee - Seats: Plus ($39 per seat): $195
$39 × 5 seats
LangChain pricing page (LangSmith) OFFICIAL 2026-11-10 - Log usage above allowance: $2,450
490,000 extra ÷ 1,000 × $5
LangChain pricing page (LangSmith) OFFICIAL 2026-11-10
Not in this total: Extra traces: 0.005 LSU each at $1.00 per LSU, so $5 per 1,000.
- Token markup: $0
markupfundinglogs and platformseats
Not priced
- Arize AX / Phoenix: No plan covers 500,000 logs
- Braintrust: Priced in GB processed and scores, not requests; no vendor-published conversion from requests to GB.
- Galileo: Annual contract pricing not confirmed on the vendor page; the page now redirects to Splunk pricing.
- W&B Weave: Priced in MB ingested; no vendor-published conversion from requests to MB.
- Maxim AI: Log limits on paid plans not published in our sources.