Logfire is built as an AI engineering platform: agent traces, evals, and LLM-as-judge scoring are first-class parts of one product and one data model. Dash0 is a capable OpenTelemetry-native observability tool with AI stapled on the side - a dashboard category plus a separate, credit-metered agent product. That gap shows up in the data model too: Dash0 caps every span at 32 attributes and 128 KiB per value, tight for the prompts, tool calls, and full message histories a real agent span carries. Logfire's only limit is a 10 MB budget with no attribute-count cap.
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Feature comparison
Quick comparison
Logfire and Dash0 compared feature by feature
Feature
Logfire
Dash0
Primary Focus
AI engineering platform - full-stack observability, evals, and agent tooling in one product
OpenTelemetry-native infrastructure and app observability, with AI stapled on as separate add-ons
AI / agent observability
Agent traces, hosted evals, LLM-as-judge scoring, and an in-product Assistant - native to the core data model
A dashboard category added on top of a metrics platform; deeper agentic analysis sold separately as Agent0
Span and attribute limits
10 MB budget per span, log, or metric point; no fixed cap on attribute count
32 attributes per span; 128 KiB per string attribute value - hard caps, published, apply to every signal
Architecture
OpenTelemetry-native, no proprietary agent
OpenTelemetry Collector-based, no proprietary agent
Query interface
PostgreSQL-compatible SQL across traces, logs, and metrics - joins, subqueries, window functions, plus MCP for agents
PromQL and Perses (CNCF projects) - shaped for metrics queries, not a general SQL surface
Key differences
Why teams choose Logfire
Built as an AI engineering platform, not observability with AI stapled on
Logfire's agent traces, hosted evals, LLM-as-judge scoring, and in-product Assistant are first-class parts of one data model and one query surface - built in, not bolted on. Dash0 is a strong general-purpose OpenTelemetry platform that added AI after the fact: a dedicated 'LLM & Agents' dashboard category sitting on top of its PromQL/Perses stack, plus a credit-metered autonomous ops agent and a per-seat code/PR insights add-on, both sold as separate products rather than shipping as part of the base platform.
Sized for what real spans actually carry
That gap shows up in the data model itself, not just the feature list. Dash0's own published limits cap every span at 32 attributes (resource, scope, span-event, and span-link attributes excluded) and 128 KiB per string attribute value - limits Dash0 says you should "never hit... with any standard observability use case." A richly-instrumented AI agent or application is not that standard case: a full prompt, message history, or tool-call payload can pass 128 KiB on its own, and so can a large SQL statement, an HTTP request or response body, or a webhook payload. Logfire's only limit is a single 10 MB budget for the whole span, log, or metric point, with no fixed cap on attribute count - roughly 80x more headroom for one oversized value.
Not just AI - every span hits the same ceiling
The 32-attribute cap is not AI-specific. OpenTelemetry's own semantic conventions for HTTP, database, RPC, and messaging calls routinely add a dozen attributes before you've added anything of your own; stack a few of those together with business context on one span and 32 stops being generous. Logfire applies the same 10 MB budget to every span regardless of signal type, with no attribute-count ceiling to design around.
SQL over everything, not PromQL over metrics
Logfire exposes traces, logs, and metrics as PostgreSQL-compatible tables: joins, subqueries, window functions, and arbitrary SQL across every signal, with the same interface available to coding agents through MCP. Dash0's query and dashboard layer is built on PromQL and Perses - real CNCF standards, but shaped for metrics queries rather than a general query language across every signal type.
Decision guide
Which should you choose?
Choose Logfire if
You want AI and agent observability built into the core platform's data model, not a dashboard category or a separately sold add-on
You send AI agent or application spans with large payloads - prompts, full message histories, SQL statements, HTTP bodies, webhook payloads - and don't want to hit a 32-attribute or 128 KiB ceiling
You want full SQL - joins, subqueries, window functions - across every signal, not a metrics-query language
Choose Dash0 if
You're already standardized on PromQL and Perses and don't need a general SQL query surface
You want a distinctly separate, credit-metered autonomous ops agent (Agent0) that can take actions like opening a pull request
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Yes, especially if you want AI built into the platform rather than bolted on afterward. Logfire is an AI engineering platform from the ground up: agent traces, evals, and LLM-as-judge scoring are first-class parts of one product and one data model, with full SQL across every signal and no hard ceiling on what a single span can carry. Dash0 is a capable OpenTelemetry-native observability tool that added AI as a dashboard category plus two separate paid products - a reasonable fit if general infrastructure monitoring is the main job and AI is secondary.
Does Dash0 truncate GenAI telemetry?
Dash0's published ingestion limits cap every span at 32 attributes (resource, scope, span-event, and span-link attributes don't count against that) and 128 KiB per string attribute value; past that, span and log string values are shortened with a "(dash0_truncated)" marker, and Dash0's own docs note that metric datapoint attributes are truncated with no marker at all. Those limits sit under what a GenAI span often needs: a full prompt, response, or tool-call payload can exceed 128 KiB on its own, and token usage, finish reasons, tool metadata, and model parameters can approach 32 attributes before anything of your own. Logfire's equivalent limit is a single 10 MB budget for the whole span, log, or metric point, with no fixed cap on attribute count; oversized values are shortened and always flagged in the record's logfire.truncated attribute.
Does this affect regular application spans too, or just AI/agent spans?
Both. Dash0's 32-attribute and 128 KiB limits apply to every span it ingests, not only AI ones. A span carrying a full SQL statement with bound parameters, an HTTP request or response body, a webhook or queue message payload, or a full stack trace can pass 128 KiB on its own - the same ceiling that trips up GenAI content. And once you combine OpenTelemetry's own semantic-convention attributes (db.*, http.*, rpc.*, messaging.*) with your own business attributes on one span, 32 is not a generous budget for a richly-instrumented application, AI or not. Logfire's 10 MB per-record budget applies across every signal the same way, with no attribute-count ceiling at all.
Is Dash0 actually OpenTelemetry-native too?
Yes - this isn't a point of difference. Dash0 is built on the OpenTelemetry Collector with no proprietary agent, the same claim Logfire makes. The real differences are in the query layer, how much a single span can carry, and how AI features are packaged - and that last one shows Dash0's roots as an infrastructure-monitoring platform that added AI later, rather than one built around AI and agent workloads from the start.
How does querying compare?
Dash0's dashboard and query layer are built on PromQL and Perses - CNCF standards, but shaped for metrics queries, not a general query language. Logfire exposes traces, logs, and metrics as PostgreSQL-compatible tables: joins, subqueries, window functions, and arbitrary SQL across every signal, plus the same interface for coding agents through MCP.
Does Dash0's AI assistant compare to Logfire's?
They're shaped differently, and the shape tells the real story. Dash0's Agent0 is a separate, credit-metered product bolted onto the base platform - useful, but external to it, and billed on its own. Logfire's AI features - agent traces, hosted evals, LLM-as-judge scoring, an in-product Assistant that answers questions about your telemetry - are native to the core product and its single data model, not a separate purchase.
What is Dash0's Agent0?
Dash0's own description is 'the autonomous production AI built into Dash0' - it can check service health, run root-cause analysis across logs/traces/metrics, and take actions like opening a pull request, billed separately in credits on top of the base observability platform.
Can I run both Logfire and Dash0?
Yes. Both ingest standard OpenTelemetry data, so nothing about instrumenting your code locks you into either one specifically.
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