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Fiddler AI alternatives: 4 apps ranked by verified data

Facts checked Nov 8, 2026AppBreakup editorialHow we rankAll LLM observability tools

Top picks

  • Evidently AI logo

    Best overall

    Evidently AI

    Open source

  • Datadog logo

    Best free option

    Datadog

    Starting price: Infrastructure Pro, $15 per host/month billed annually

  • Evidently AI logo

    Best open source

    Evidently AI

    Open source

Common reasons people leave Fiddler AI: free plan covers guardrails only, not full observability, and not open source, unlike Evidently or Langfuse. We ranked 4 alternatives by how directly each one replaces Fiddler AI, then by reviews, real visits and how recently each app's facts were checked against its own website. Evidently AI currently ranks first.

Quick comparison

#AppPricingVerified priceOpen sourcePlatformsVerified factsScore
1Evidently AI logoEvidently AIOpen source—YesSelf-hosted, Web4 of 468.8
2Datadog logoDatadogFree plan + paidInfrastructure Pro, $15 per host/month billed annuallyNoWeb, iOS, Android6 of 766.1
3New Relic logoNew RelicFree plan + paid$10 for the first full user, then $99 per user (Standard)NoWeb, iOS, Android7 of 757.5
4Weights & Biases logoWeights & BiasesFree plan + paidFrom $60 a month (Pro), billed monthlyNoWeb, iOS6 of 651.2
  1. Evidently AI logo

    1. Evidently AITop pick

    Best for: ML and data teams who want code-first LLM evals and model drift monitoring on their own infrastructure

    Open sourceSelf-hostableSelf-hosted, Web

    68.8

    score / 100

    Why switch from Fiddler AI

    Open-source and free to self-host, covering the same mix of ML drift monitoring and LLM evaluation.

    Pros

    • Apache 2.0 licensed, with no paid tier needed for the core features
    • Covers both classic ML drift monitoring and LLM and agent evaluation
    • Over 100 built-in metrics, plus custom checks and LLM-as-judge
    • Evaluations run as tests, so they slot into CI pipelines

    Cons

    • Code-first Python library, so non-engineers will struggle to set up checks
    • You run and maintain the self-hosted platform yourself
    • Lighter on prompt management and production tracing than LLM-first tools
    Visit Evidently AI Details and reviews
    How this score is calculated
    Editorial fit ×0.3100
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.15100
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is Evidently AI a good Fiddler AI alternative?

    Verified facts

    4 of 4 verified
    License
    Apache 2.0
    Checked Nov 8, 2026github.com(opens source in a new tab)
    Built-in metrics
    100+
    Checked Nov 8, 2026evidentlyai.com(opens source in a new tab)
    Self-hosting
    Yes
    Checked Nov 8, 2026docs.evidentlyai.com(opens source in a new tab)
    Covers
    LLMs, RAG, agents and ML models
    Checked Nov 8, 2026evidentlyai.com(opens source in a new tab)
  2. Datadog logo

    2. Datadog

    Best for: Cloud-heavy teams that want metrics, traces, logs and alerts in one hosted product and can budget for it

    Free plan + paidWeb, iOS, Android

    66.1

    score / 100

    Why switch from Fiddler AI

    LLM observability alongside the APM and infrastructure monitoring many enterprises already pay for.

    Pros

    • Very wide integration catalogue that works with little setup
    • Metrics, traces and logs are linked in one interface
    • Mature dashboards, monitors and on-call features

    Cons

    • Per-product, per-host pricing makes bills hard to forecast
    • Custom metrics and log volume get expensive quickly
    • No self-hosted option
    Visit Datadog Details and reviews
    How this score is calculated
    Editorial fit ×0.346
    Reviews ×0.363
    Clicks (90 days) ×0.15100
    Freshness ×0.1590
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is Datadog a good Fiddler AI alternative?

    Verified facts

    6 of 7 verified
    Starting price
    Infrastructure Pro, $15 per host/month billed annually
    Checked Nov 8, 2026datadoghq.com(opens source in a new tab)
    Free tier
    Up to 5 hosts, 1-day metric retention
    Source changed Nov 8, 2026datadoghq.com(opens source in a new tab)
    Free trial
    14 days
    Checked Nov 8, 2026datadoghq.com(opens source in a new tab)
    Integrations
    1,000+
    Checked Nov 8, 2026datadoghq.com(opens source in a new tab)
    Enterprise plan
    $23 per host/month billed annually
    Checked Nov 8, 2026datadoghq.com(opens source in a new tab)
    APM plan
    From $31 per host/month
    Checked Nov 8, 2026datadoghq.com(opens source in a new tab)
    Free plan
    Yes, up to 5 hosts with 1-day metric retention
    Checked Nov 8, 2026datadoghq.com(opens source in a new tab)
  3. New Relic logo

    3. New Relic

    Best for: Teams that want full-stack APM with predictable data-based pricing and a usable free tier

    Free plan + paidWeb, iOS, Android

    57.5

    score / 100

    Why switch from Fiddler AI

    AI monitoring sits in the same APM platform as app traces and logs, handy for teams already paying for New Relic.

    Pros

    • Perpetual free tier with a meaningful monthly data allowance
    • One query language across all telemetry types
    • Wide language agent support plus OpenTelemetry ingest

    Cons

    • Full-platform user seats are expensive on paid tiers
    • Interface has many overlapping views to learn
    • Hosted only
    Visit New Relic Details and reviews
    How this score is calculated
    Editorial fit ×0.338
    Reviews ×0.363
    Clicks (90 days) ×0.1550
    Freshness ×0.15100
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is New Relic a good Fiddler AI alternative?

    Verified facts

    7 of 7 verified
    Free tier
    100 GB data ingest/month
    Checked Nov 8, 2026newrelic.com(opens source in a new tab)
    Data price
    $0.40/GB beyond 100 GB free
    Checked Nov 8, 2026newrelic.com(opens source in a new tab)
    Free full user
    1
    Checked Nov 8, 2026newrelic.com(opens source in a new tab)
    Basic users
    Unlimited, free
    Checked Nov 8, 2026newrelic.com(opens source in a new tab)
    Starting price
    $10 for the first full user, then $99 per user (Standard)
    Checked Nov 8, 2026newrelic.com(opens source in a new tab)
    Pro plan
    $349 per full user/month, annual commitment
    Checked Nov 8, 2026newrelic.com(opens source in a new tab)
    Free plan
    Yes, 100 GB data ingest/month and 1 full user
    Checked Nov 8, 2026newrelic.com(opens source in a new tab)
  4. Weights & Biases logo

    4. Weights & Biases

    Best for: ML researchers and teams who want polished hosted experiment tracking and LLM evaluation

    Free plan + paidWeb, iOS

    51.2

    score / 100

    Why switch from Fiddler AI

    Hosted experiment tracking plus LLM tracing and evaluation, popular with model-training teams.

    Pros

    • Very quick to add to existing training code
    • Integrations with nearly every major ML library
    • Covers experiments, sweeps, artifacts and LLM tracing in one place
    • Free for academic research

    Cons

    • Free plan has tight storage and seat limits
    • Costs grow with storage and data ingestion
    • Hosted product; the tracking server isn't open source like ClearML's
    Visit Weights & Biases Details and reviews
    How this score is calculated
    Editorial fit ×0.341
    Reviews ×0.363
    Clicks (90 days) ×0.150
    Freshness ×0.15100
    Votes ×0.150

    0 counted reviews, 0 up and 0 down votes. Full formula

    Is Weights & Biases a good Fiddler AI alternative?

    Verified facts

    6 of 6 verified
    Free plan
    Yes, $0 a month
    Checked Nov 8, 2026wandb.ai(opens source in a new tab)
    Pro plan
    From $60/month
    Checked Nov 8, 2026wandb.ai(opens source in a new tab)
    Free trial
    30 days (Pro)
    Checked Nov 8, 2026wandb.ai(opens source in a new tab)
    Academic use
    Free
    Checked Nov 8, 2026wandb.ai(opens source in a new tab)
    Mobile app
    iOS
    Checked Nov 8, 2026wandb.ai(opens source in a new tab)
    Starting price
    From $60 a month (Pro), billed monthly
    Checked Nov 8, 2026wandb.ai(opens source in a new tab)

The best Fiddler AI alternative for…

The highest-ranked app in this list for each need.

Evidently AI logo

Best Fiddler AI alternative for most people

Evidently AI

Open-source and free to self-host, covering the same mix of ML drift monitoring and LLM evaluation.

Evidently AI logo

Best Fiddler AI alternative for a free option

Evidently AI

Open-source and free to self-host, covering the same mix of ML drift monitoring and LLM evaluation.

Datadog logo

Best Fiddler AI alternative for a free plan you can upgrade

Datadog

LLM observability alongside the APM and infrastructure monitoring many enterprises already pay for.

Evidently AI logo

Best Fiddler AI alternative for open source

Evidently AI

Open-source and free to self-host, covering the same mix of ML drift monitoring and LLM evaluation.

Evidently AI logo

Best Fiddler AI alternative for self-hosting

Evidently AI

Open-source and free to self-host, covering the same mix of ML drift monitoring and LLM evaluation.

New Relic logo

Best Fiddler AI alternative for iPhone and Android

New Relic

AI monitoring sits in the same APM platform as app traces and logs, handy for teams already paying for New Relic.

Weights & Biases logo

Best Fiddler AI alternative for working in the browser

Weights & Biases

Hosted experiment tracking plus LLM tracing and evaluation, popular with model-training teams.

Fiddler AI alternatives: common questions

What is the best alternative to Fiddler AI?

Evidently AI ranks first right now. Open-source and free to self-host, covering the same mix of ML drift monitoring and LLM evaluation. Datadog and New Relic follow it in our ranking.

Fiddler AI vs Evidently AI: what's the difference?

Fiddler AI is free with paid plans; Evidently AI is free and open source. Evidently AI is open source and Fiddler AI is not. Both run on Web.

Is Fiddler AI free?

Fiddler AI is free with paid plans. Free plan: Real-time guardrails; Developer plan: $0.002 per trace. Checked on Fiddler AI's own site, November 2026.

How much do Fiddler AI alternatives cost?

Verified prices for the top-ranked Fiddler AI alternatives: Datadog, Infrastructure Pro, $15 per host/month billed annually; New Relic, $10 for the first full user, then $99 per user (Standard); Weights & Biases, From $60 a month (Pro), billed monthly. Each price was checked on the app's own site; see each card below for the date and source.

Is there a free alternative to Fiddler AI?

Yes. Evidently AI (open source), Datadog (free plan + paid), New Relic (free plan + paid) and Weights & Biases (free plan + paid) have a free option. Check each app's verified facts for current plan limits.

Is there an open-source alternative to Fiddler AI?

Yes: Evidently AI. Evidently AI can also be self-hosted.

Why do people switch from Fiddler AI?

The complaints we hear most: free plan covers guardrails only, not full observability; not open source, unlike Evidently or Langfuse; enterprise features and on-prem deployment need a sales contract.

How is this list ranked?

Every app is scored with the same published formula: how directly it replaces Fiddler AI, reviews (weighted by verification), visits from AppBreakup, how recently its facts were checked against its own website, and reader votes.