Aider vs Reason

Summary

Aider vs Reason (Coding Agents (CLI & Cloud)). Agent test scores: Aider 9.3/10, Reason 8.6/10. Aider scored 0.7 higher overall in our separate rubric v0.1 tests (editions and tasks can differ — see Edition tested and the notes below). Pricing: Aider — Free open source (Apache 2.0); pay your LLM provider; Reason — Free plan (no included agent quota; bring your own model key or buy credits); Pro $20/mo with a 7-day trial; Max $200/mo (seen in the app, 2026-10-17).

Every fact on this page comes from our tool records and test logs. Last updated:

Key facts

Aider

VibeToolRank score
9.3/10
Last tested
2026-10-16
Runs
3 runs
Outcome score
9/10
Edition tested
Aider 0.86.2 CLI with OpenRouter free model cohere/north-mini-code:free
Free plan, as measured
About 1.0K tokens sent and 1.3K received per bugfix run, $0 on a free OpenRouter model
Free plan
Yes: free tool, BYO API key or local models
Price
Free open source (Apache 2.0); pay your LLM provider
Pricing checked
2026-10-16

Reason

VibeToolRank score
8.6/10
Last tested
2026-10-18
Runs
3 runs
Outcome score
8/10
Edition tested
Reason Agent 1.10 (cloud API), Free plan, scratch sessions with our OpenRouter key on the free model cohere/north-mini-code:free
Free plan, as measured
About 84-126K input and 2-4K output tokens per bugfix run, $0 on a free OpenRouter model (12 OpenRouter free requests for 3 runs)
Free plan
Partly: the Free plan includes no agent runs (our API check showed the quota exhausted at zero usage); you can bring your own model API key. Reason Network is free.
Price
Free plan (no included agent quota; bring your own model key or buy credits); Pro $20/mo with a 7-day trial; Max $200/mo (seen in the app, 2026-10-17)
Pricing checked
2026-10-17

Side by side

FieldAider Reason
What it isAiderOpen-source AI pair programming in the terminal.ReasonAutonomous cloud coding agent for GitHub that opens pull requests; its new Reason Network lets your coding agents talk to each other.
PricingAiderFree open source (Apache 2.0); pay your LLM providerReasonFree plan (no included agent quota; bring your own model key or buy credits); Pro $20/mo with a 7-day trial; Max $200/mo (seen in the app, 2026-10-17)
Free tierAiderYes: free tool, BYO API key or local modelsReasonPartly: the Free plan includes no agent runs (our API check showed the quota exhausted at zero usage); you can bring your own model API key. Reason Network is free.
Pricing verifiedAider2026-10-16Reason2026-10-17
Edition testedAiderAider 0.86.2 CLI with OpenRouter free model cohere/north-mini-code:freeReasonReason Agent 1.10 (cloud API), Free plan, scratch sessions with our OpenRouter key on the free model cohere/north-mini-code:free
Tested onAider2026-10-16Reason2026-10-18
Outcome scoreAider9Reason8
Speed scoreAider10Reason10
Cost scoreAider10Reason10
Developer experience scoreAider8Reason6
Reliability scoreAider10Reason10
Overall scoreAider9.3Reason8.6

What our tests found

Aider

3/3 runs fixed our seeded cart bug (4/4 tests pass) in 9-13s with a free OpenRouter model, without touching the test file. Install needed uv because pip was blocked on the system Python.CLI, free model

Pros
  • Fixed the seeded bug correctly in 3 of 3 runs, in 9-13 seconds
  • Works with free OpenRouter models, so our test cost $0
  • Built-in --auto-test loop runs your tests after each edit
Cons
  • pip install was refused on Debian's system Python; we needed uv
  • Unattended runs need several flags (--yes-always, --message, --test-cmd)
  • Free model slugs change; one we tried returned 'unavailable for free'

Who it’s for: Terminal-first developers who want an open-source pair programmer that works with any model, including free ones.

Reason

3/3 runs fixed our seeded cart bug (4/4 tests pass) in 20-36s of agent time with a free OpenRouter model, $0. On the Free plan the agent's cloud computer doesn't start, so it can't run tests or edit a repo itself; it returned the fixed file and we applied it.cloud free plan

Pros
  • Fixed the seeded bug correctly in 3 of 3 runs, in 20-36 seconds
  • Lets you bring your own model key and pin a free OpenRouter model, so our test cost $0
  • The API reports outcome, cost and token usage for every session
Cons
  • On the Free plan the cloud computer won't start, so the agent can't run tests, edit a repo or open a PR
  • The agent kept retrying tools on the missing machine, using 84-126k input tokens for a 7-line fix
  • The session's result field is truncated; the full answer is only in the events log

Who it’s for: Developers who want a cloud agent to work GitHub issues and coordinate with Claude Code, Codex and teammates' agents.

Verdict

Scores use rubric v0.1 from separate runs. Editions and tasks can differ (see Edition tested and What our tests found); some tests were a single run, which caps reliability scores. Overall: Aider 9.3, Reason 8.6. Check the free-tier limits above against your project before choosing.

FAQ

Which is better, Aider or Reason?

In our tests Aider scored higher overall (9.3/10 vs 8.6/10). Scores use the same rubric (v0.1) but came from separate runs; editions and tasks may differ (see Edition tested and test summaries), so check the per-dimension scores for what matters to you.

Is Aider free?

Yes: free tool, BYO API key or local models (pricing checked 2026-10-16).

Is Reason free?

Partly: the Free plan includes no agent runs (our API check showed the quota exhausted at zero usage); you can bring your own model API key. Reason Network is free. (pricing checked 2026-10-17).

How much does Aider cost compared with Reason?

Aider: Free open source (Apache 2.0); pay your LLM provider. Reason: Free plan (no included agent quota; bring your own model key or buy credits); Pro $20/mo with a 7-day trial; Max $200/mo (seen in the app, 2026-10-17).

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Scores come from our own tests and are never for sale; sponsored placements are always labelled. Some links are affiliate links (currently Railway). Disclosure